ferrite machining?
Yzordderrex
I have a short 1" long by 1" dia. rod ( i know, i know, a personal
problem) and I would like to have a grove machined into it to accept a
few turns of wire. there will then be a bobbin slipped over that with
the secondary on it.
I suppose this might be done with some type of grinder as well.
Just curious to know what machining options are available for ferrite.
regards,
Bob
MooseFET
Grinding is the way to go. If you want to cut something that
you would normally do with a lathe in metal, consider a tool
post mounted grinder. Watch the temperature rise.
John Larkin
Maybe a dremel with a diamond wheel?
John
BlindBaby
After the grooves get ground (any cutting attempt will result in
fracture), you need to cover the rod with transformer tape to insulate it
from your primary wire.
If you make an open ended core transformer, it will be pretty leaky
unless you use a closed loop core arrangement.
You would probably be better off with a pot core.
I would use a dremel tool and grinding or cutting (abrasive cutting)
disc attached.
If you are making a large groove for a single layer of larger wire the
grooves will allow the wire profile to sit a bit lower.,
If you are using fairly small primary wire, you do not need the grooves
at all.
Temperature rise? They are not magnets. There are no properties to
lose via introduction of heat.
John Larkin
Here's a tiny pickup coil we wound in a slot that we turned into a
delrin rod.
ftp://jjlarkin.lmi.net/BrassThing.jpg
This was snooping eddy current fields inside a superconductive magnet.
The n*A is tiny, so we got nanovolt signals. And we had to integrate
the voltage to get field intensity.
John
Mike Harrison
Ferrite is pretty much like ceramic, so you're talking grinding, preferably with diamond
BlindBaby
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
Pretty small wire. Looks like #43 or even a 50 series size. Very fine
size.
>And we had to integrate
>the voltage to get field intensity.
>
No shit? Isn't that how all of us would have to do it?
Was it easy to calibrate the circuit output to give accurate readings
or was it a little mushy at the low end?
Instead of a slot, I would have wound it, locked the winding with epoxy
or other suitable material, and then I would have knocked that little
'hat' off the top of it, making it less of a complete flux path at the
bobbin level. The open ended coil would then 'accept' the flux inside
the reading area better. Kind of follows as to the same reason that a
toroid would be a bad choice for this. You actually want an open
magnetic path on this as opposed to normal coil making paradigms where
one want to reduce leakage to a minimum.
BlindBaby
wrote:
Yep. Not nearly as hard as ceramics are. Not even as hard as your
kitchenware actually. Fairly crumbly even, by comparison. But yes,
grinding is the only way to remove media from these components because
any machine tool application may shock the remaining media, causing
unseen microfractures (or seen) that damage the operational
characteristic of the media. If the rod is the center piece for a closed
loop core, then the mating ends have to be kept smooth and should not be
touched at all. The coupling at that interface is important.
If it is an open ended transformer that does not have a closed loop
core, I cannot see how trying to top out some efficiency by this primary
placement even matters. Put it on top of the secondary.
If isolation is the issue, put the primary inside a Teflon tube, if the
turns count is low enough.
There certainly is no 'major' efficiency to be gained by tightly mating
the primary wire to the core. Especially if it is an open ended core
configuration. Or maybe that is why it DOES have to be tight. It is so
lossy that he needs it that close. If that is the case, this situation
should be using a fully closed loop pot core or C-I core or the like.
Bill Sloman
Wrong. Permeability drops with rising temperature, and leakage flux
rises. Ferrite cores don't have to get very hot before they become
magnetically insignificant. Read the relevant data sheets for the
material used to make your core on the manufactuere's web site.
--
Bill Sloman, Nijmegen
BlindBaby
You are wrong. An overheated magnet will lose some of its magnetization
level after it cools. An overheated ferrite core will have the same
characteristics after it cools.
> Permeability drops with rising temperature, and leakage flux
>rises.
But getting it hot while grinding it does not hurt it once it cools
down, idiot. Nobody said anything about heating it in circuit.
> Ferrite cores don't have to get very hot before they become
>magnetically insignificant.
The temp is upwards of 200 to 600F, dipshit.
> Read the relevant data sheets for the
>material used to make your core on the manufactuere's web site.
Again, applying a thermal precaution to a grinding operation is NOT
required. The medium remains unchanged after the grinding is completed.
It is the same *when it is at room temp* before grinding, as it is
*when it is at room temp* after severe heating has been introduced from
having been ground.
Nobody said a goddamned thing about it being hot during operation or
while in use.
Learn to read, dumbfuck.
John Larkin
<BlindMel...@wellnevergetthatonethealbumcover.org> wrote:
"No fooling" would have been more appropriate, but for the fetish
thing.
>
> Was it easy to calibrate the circuit output to give accurate readings
>or was it a little mushy at the low end?
Integrator drift was a problem, taking data out to a second or so. We
had an analog switch auto-zeroing the thing every shot, and that was
barely enough to get good data. Should have ovenized it or something.
>
> Instead of a slot, I would have wound it, locked the winding with epoxy
>or other suitable material, and then I would have knocked that little
>'hat' off the top of it, making it less of a complete flux path at the
>bobbin level. The open ended coil would then 'accept' the flux inside
>the reading area better. Kind of follows as to the same reason that a
>toroid would be a bad choice for this. You actually want an open
>magnetic path on this as opposed to normal coil making paradigms where
>one want to reduce leakage to a minimum.
The black part is delrin, not ferrite, so it doesn't matter where the
slot is located. The greenish thing is a fiberglass tube, nice for
routing the wires but not good for machining slots into.
John
lang...@fonz.dk
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Fri, 11 Jun 2010 09:33:33 -0700, BlindBaby
you had me puzzled for a while on how you got a piece of ferrite
near a superconduction magnet, or more importantly away from it :)
-Lasse
BlindBaby
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>> No shit? Isn't that how all of us would have to do it?
>
>"No fooling" would have been more appropriate, but for the fetish
>thing.
It is NOT a fetish, dumbfuck. Get over it, John. You are wrong. It
is COMMON usage.
YOU are the idiot that thinks that you are a psychoanalyst. You are
the idiot that doesn't even have the aptitude for certain aspects of your
chosen profession. What makes you think that anyone would put any
credence in your feeble jerk-off attempts at acting like you are an
authority in any other discipline?
You are really and truly about as stupid as it gets. That makes my
calls all these years, pretty much right on the mark.
It pretty much comes down to this: "Grow the fuck up, dumbshit."
BlindBaby
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
Oh... so it is 'core free'. In that case, I would have turned the coil
on end and encapsulated it into a bead of epoxy. That would make it a
component easy to install into/onto any type of 'wand' or whatever device
to allow the transducer to be placed into the sampling zone.
As for the fiberglass rod, a slot would be difficult, but a mere
cut-to-depth at the end of it is possible, which would let it be able to
be used for the windings without the second, Delrin element. The winding
wouldn't really need a 'hat' as long as you lock it all down after
winding it.
It would seem like a small open ended core of some type would amplify
the 'signal' better too. Maybe too much. Cause it to be a little
sluggish <sic> :-) too.
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Fri, 11 Jun 2010 10:33:17 -0700 (PDT),Bill Sloman
True, but not what you said.
> > Permeability drops with rising temperature, and leakage flux
> >rises.
>
> But getting it hot while grinding it does not hurt it once it cools
> down, idiot. Nobody said anything about heating it in circuit.
Again true, but - again - not what you said.
> > Ferrite cores don't have to get very hot before they become
> >magnetically insignificant.
>
> The temp is upwards of 200 to 600F, dipshit.
The managanese-zince ferrites that we use for frequencies up to about
a 1MHz have Curie points between 125C and 150C - 260 to 300F. Nickel-
zinc ferrites for higher frequency work can have higher Curie
temperatures - Philips listed one (good to 50MHz) that had a Curie
point above 500C - 900F - though another crapped out at 125C.
150C isn't impossibly hot for some kinds of working circuits.
> > Read the relevant data sheets for the
> >material used to make your core on the manufactuere's web site.
>
> Again, applying a thermal precaution to a grinding operation is NOT
> required. The medium remains unchanged after the grinding is completed.
Correct.
> It is the same *when it is at room temp* before grinding, as it is
> *when it is at room temp* after severe heating has been introduced from
> having been ground.
>
> Nobody said a goddamned thing about it being hot during operation or
> while in use.
On the other hand, you didn't phrase your comment to exclude those
situations.
> Learn to read, dumbfuck.
Learn to write in a way that doesn't make claims that you didn't
intend.
--
Bill Sloman, Nijmegen
John Larkin
<BlindMel...@wellnevergetthatonethealbumcover.org> wrote:
This was used to measure NMR gradient field eddy current effects
inside a roughly 150 kilogauss magnetic field. Any core would
saturate, not to mention mess up what I'm trying to measure.
It would have been nice to have more signal. More turns of finer wire.
John
Sjouke Burry
John Fields
<bill....@ieee.org> wrote:
>Learn to write in a way that doesn't make claims that you didn't
>intend.
---
Unnecessarily nasty when, in all fairness, the thread _is_ about
machining ferrite, and the heat he was referring to (which I think
most of the rest of us picked up on) could only have been caused by
the grinding operation.
John Fields
>It would have been nice to have more signal. More turns of finer wire.
---
If frogs had wings?
BlindBaby
Pretty easy to grind with normal emery grit products too. Even those
'sut-off-saw' discs will work.
Jim Yanik
news:4c12c34e$0$14129$703f...@textnews.kpn.nl:
DAGS for "ferrite machining".
>>
>> regards,
>> Bob
>>
> Diamond rotating saw disk??
>
it's a ceramic;grinding can introduce stress fractures(cracks).
--
Jim Yanik
jyanik
at
localnet
dot com
BlindBaby
It is closer to an epoxy bound sintered matrix than a ceramic.
Ceramics get post sintering firings that harden them further.
Machining with striking tools like a lathe bit or mill head cutting
flute/tooth will CERTAINLY introduce fractures.
Grinding is the ONLY 'correct' type of machining to remove media from
them. They are not 'fired' like a ceramic and do not have the hardness
that a ceramic acquires... AT ALL. They ARE too hard to machine, but
they are not too hard to grind media from.
MooseFET
The one partedness can be lost through the heat rise at the machined
point. They don't conduct heat well and neither does the grinder.
I stand by my suggestion that temperature rise be watched.
MooseFET
[...]
> Wrong. Permeability drops with rising temperature, and leakage flux
> rises. Ferrite cores don't have to get very hot before they become
> magnetically insignificant. Read the relevant data sheets for the
> material used to make your core on the manufactuere's web site.
This has nothing to do with the reason to watch the temperature rise.
It is just plain a mechanical issue. The material is brittle and a
bad
conductor of heat.
BlindBaby
wrote:
>On Jun 12, 12:07 am, BlindBaby
Are you trying to say that the particles "meld" together at the
grinding site?
Well, they don't. It is mostly abrasive cutting, per se, not so much
grinding like one does when trying to make a bar of steel shorter or the
like, THAT heat soaks in and remains and builds and burns of the metal
and annealing/hardening cycle occur. This ain't a steel bar. It grinds
far easier, and it does not build much heat because it grinds easier.
I have modified more pot cores for production than you have likely ever
seen in your life. I know exactly how easy it is to work and what tools
are best to work it with.
You likely do not know what the word 'work' means since you are so
paranoid about thinking that it would soak up so much heat or even have
local heat issues when it will not.
It would not change anything even one ten thousandth of one percent if
it did, which it doesn't, and that would only affect the are ground.
It does not happen, and your paranoia is nothing more than a fantasy...
of yours.
BlindBaby
wrote:
>On Jun 12, 1:33 am, Bill Sloman <bill.slo...@ieee.org> wrote:
And grinding it doesn't hurt it at all. It got heated when it got
made. It is a sintered, stamped, baked manufacturing process.
Bill Sloman
> On Fri, 11 Jun 2010 14:54:12 -0700 (PDT),Bill Sloman
>
> >Learn to write in a way that doesn't make claims that you didn't
> >intend.
>
> ---
> Unnecessarily nasty when, in all fairness, the thread _is_ about
> machining ferrite, and the heat he was referring to (which I think
> most of the rest of us picked up on) could only have been caused by
> the grinding operation.
Perhaps. But you snipped his " Learn to read, dumbfuck." which - to my
mind - does justify a tolerably nasty clsong sentence.
And while one could assume that he was talking about the heat
generated by the grinding operation, what he said could certainly be
interpreted to mean that soft ferrites didn't have a Curie
temperature. You are prone quoting stuff taken out of context - as you
have here - and may not be sensitive to the risk.
--
Bill Sloman, Nijmegen
amdx
"Yzordderrex" <powersu...@netzero.net> wrote in message
news:a9090b31-6b08-4114...@u7g2000yqm.googlegroups.com...
> Does anyone know of ferrrite can be turned on a lathe?
>
> I have a short 1" long by 1" dia. rod ( i know, i know, a personal
> problem) and I would like to have a grove machined into it to accept a
> few turns of wire. there will then be a bobbin slipped over that with
> the secondary on it.
>
> I suppose this might be done with some type of grinder as well.
>
> Just curious to know what machining options are available for ferrite.
>
> Bob
>
Maybe instead of all the grinding and since it is a rod with its incomplete
magnetic path. Can you install your bobbin, wind your secondary and
add the insulation amount of insulation needed and then put your primary
on the outside? Or wind your primary on the ferrite and use a larger bobbin,
( know limited sizes)
Do you have a high voltage problem you're working around?
Mike
Grant
I just spent some time with a high speed hobby drill, various grinding
attachments and a then piece of ferrite, a figure eight buckle type they
wind those mains filters on, the type with sprocket teeth on the coil
former so the ferrite is one piece.
Anyway, 150 grit diamond tool rips into the stuff, black dust everywhere,
easy to fracture pieces off, very harsh if one applies too much pressure.
The sanders and other grinders a bit more gentle, most gentle (but slow)
was the thin cutoff wheel when use with light pressure and kept moving
to avoid localised heating. If I tried too hard to grind one spot, the
ferrite would fracture from the hot spot, through several mm of ferrite.
Machining ferrite is easy, with a little practice to develop a feel
for what is easy, and stuff that is dangerous in the sense of risking
fracturing the job.
Diamond tools would need to be a lot finer than 150 grit to lessen the
impact and give a smoother finish -- easy to control with light pressure
and rips out the material quickly.
Interesting stuff to play with. And try different tool speeds, the
abrasion rate doesn't necessarily go up with speed. Odd?
Grant.
--
http://bugs.id.au/
John Fields
<bill....@ieee.org> wrote:
>On Jun 12, 1:33 am, John Fields <jfie...@austininstruments.com> wrote:
>> On Fri, 11 Jun 2010 14:54:12 -0700 (PDT),Bill Sloman
>>
>> <bill.slo...@ieee.org> wrote:
>> >Learn to write in a way that doesn't make claims that you didn't
>> >intend.
>>
>> ---
>> Unnecessarily nasty when, in all fairness, the thread _is_ about
>> machining ferrite, and the heat he was referring to (which I think
>> most of the rest of us picked up on) could only have been caused by
>> the grinding operation.
>
>Perhaps. But you snipped his " Learn to read, dumbfuck." which - to my
>mind - does justify a tolerably nasty clsong sentence.
---
His: "Learn to read, dumbfuck." had nothing technical to add to the
discussion, so I snipped it for that reason.
More to the point, if what you're saying is true, then faulting him
for _your_ misinterpretaion of his statement(s) is an error on your
part.
That is, since the subject of the thread is "ferrite machining?", one
with a modicum of sense would infer that the heat referred to was
generated purely by mechanical means and that the Curie temperature of
the material, at that point was immaterial.
I believe mention was also made of the fact that the material wasn't a
magnet, so that should have been a further clue that the Curie
temperature of the material was immaterial at that point.
---
>And while one could assume that he was talking about the heat
>generated by the grinding operation, what he said could certainly be
>interpreted to mean that soft ferrites didn't have a Curie
>temperature.
---
Perhaps, but it would have to have been "interpreted" by someone
ignorant of American English usage or ignorant of the differences
between hard and soft ferrites.
---
>You are prone quoting stuff taken out of context - as you
>have here - and may not be sensitive to the risk.
---
Ah, I see...
It _is_ an English problem.
It should be, "You are prone to quoting"..., otherwise I'd be in
repose while quoting.
In any case, your argument is nonsensical since you're the one who
misinterpreted what was being said, thus it's _you_ who has been
quoting out of context.
JF
mpm
>
> - Show quoted text -
With no dog in this fight, I have to agree with Sloman.
In technical writing, you cannot fault the reader for not
understanding what the writer intended.
The burden placed on the writer in these situations is exactly what
separates technical writing from poetry, for example.
Rather than annoying each other over syntax, it might be easier to
just acknowledge that even more demands are placed on the technical
writer in informal settings such as Usegroups. There will always be a
trade-off between brevity and understanding, for all participants.
I'm sure if the author had the time and inclination, he could have
drafted something so succinct and clear, that nobody could
misinterpret his intent. But is that really practical in a forum like
this? Or it is just easier to call each other names?
Archimedes' Lever
<bill....@ieee.org> wrote:
>to mean that soft ferrites didn't have a Curie
>temperature.
Bullshit.
Archimedes' Lever
I already posed this question.
Archimedes' Lever
Ever seen a pot core pair with mirror polished mating faces?
They are abrasively finished.
BlindBaby
<jfi...@austininstruments.com> wrote:
>
>That is, since the subject of the thread is "ferrite machining?", one
>with a modicum of sense would infer that the heat referred to was
>generated purely by mechanical means and that the Curie temperature of
>the material, at that point was immaterial.
Jeez, I wish I could expound facts the way you do.
BlindBaby
>With no dog in this fight, I have to agree with Sloman.
>In technical writing, you cannot fault the reader for not
>understanding what the writer intended.
That's not what he did. He faulted him for the parts he failed to
read.
Like the TOPIC HEADER.
John Larkin
Fetish.
BlindBaby
>
>Rather than annoying each other over syntax, it might be easier to
>just acknowledge that even more demands are placed on the technical
>writer in informal settings such as Usegroups. There will always be a
>trade-off between brevity and understanding,
Horseshit. Anyone with any NORMAL modicum of common sense, would have
been able to discern that I referred to heat generated by the tooling. I
did, after all, make that response to someone that made the statement
that the grinding temp rise needed to be guarded against.
BlindBaby
> But is that really practical in a forum like
>this? Or it is just easier to call each other names?
It is quite easy to cull the idiots from those with half a clue.
Any fucking monkey could have been able to tell what I was talking
about.
Any fucking loser would have morphed it into me making an improper claim
about magnetic properties and temperature, while in operation.
So, yeah, casual conversation here allows us to see the dopes easier.
The remark was so blatantly obvious as to the point it was making that
ANYONE that claims otherwise exposes him or herself as the "I was only
there to get the degree" idiots that they are.
John Larkin
<OneBi...@InfiniteSeries.Org> wrote:
> Yeah... you. A retarded behavior fetish. You cannot stop acting
>retarded.
And you can't keep from mentioning excrement.
John
John Larkin
<BlindMel...@wellnevergetthatonethealbumcover.org> wrote:
>On Sat, 12 Jun 2010 07:49:20 -0700 (PDT), mpm <mpmi...@aol.com> wrote:
>
>>
>>Rather than annoying each other over syntax, it might be easier to
>>just acknowledge that even more demands are placed on the technical
>>writer in informal settings such as Usegroups. There will always be a
>>trade-off between brevity and understanding,
>
> Horseshit.
Fetish.
John Fields
wrote:
>With no dog in this fight, I have to agree with Sloman.
>In technical writing, you cannot fault the reader for not
>understanding what the writer intended.
>The burden placed on the writer in these situations is exactly what
>separates technical writing from poetry, for example.
>
>Rather than annoying each other over syntax, it might be easier to
>just acknowledge that even more demands are placed on the technical
>writer in informal settings such as Usegroups. There will always be a
>trade-off between brevity and understanding, for all participants.
>I'm sure if the author had the time and inclination, he could have
>drafted something so succinct and clear, that nobody could
>misinterpret his intent. But is that really practical in a forum like
>this? Or it is just easier to call each other names?
---
Nicely stated, thank you. :-)
I agree with you that it's often impractical to remove all ambiguity
in an effort to avoid misinterpretation by a reader.
Having said that though, I believe it's encumbent on the reader
(especially someone who pretends to intellectual superiority, like
Sloman) to glean meaning from context, where possible, and reply
appropriately.
In this instance, I believe, he did not and either intentionally
latched onto a meaning taken out of context, for the purpose of sowing
discord, or else made an honest mistake by being ignorant of the
differences between hard and soft ferrites.
And, yes, it's always easier to name-call. ;)
John Fields
---
Thank you, that's very kind. :-)
John Fields
---
Troublemaker.
John Fields
<jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>On Sat, 12 Jun 2010 08:20:17 -0700, Archimedes' Lever
><OneBi...@InfiniteSeries.Org> wrote:
>
>>On Sat, 12 Jun 2010 08:16:47 -0700, John Larkin
>><jjla...@highNOTlandTHIStechnologyPART.com> wrote:
>>
>>>On Sat, 12 Jun 2010 08:05:39 -0700, Archimedes' Lever
>>><OneBi...@InfiniteSeries.Org> wrote:
>>>
>>>>On Sat, 12 Jun 2010 02:05:35 -0700 (PDT), Bill Sloman
>>>><bill....@ieee.org> wrote:
>>>>
>>>>>to mean that soft ferrites didn't have a Curie
>>>>>temperature.
>>>>
>>>> Bullshit.
>>>
>>>Fetish.
>>>
>> Yeah... you. A retarded behavior fetish. You cannot stop acting
>>retarded.
>
>And you can't keep from mentioning excrement.
---
You certainly seem to be drawn in by its mention,
BlindBaby
<jfi...@austininstruments.com> wrote:
>In this instance, I believe, he did not and either intentionally
>latched onto a meaning taken out of context, for the purpose of sowing
>discord, or else made an honest mistake by being ignorant of the
>differences between hard and soft ferrites.
>
>And, yes, it's always easier to name-call. ;)
I go with the sow discord effort.
I do not afford him enough credence to have the brains to have actually
been able to glean the glaringly obvious meaning that I was conveying.
We'll yet see the other fellow coming back to describe how the
individual magnetic cells of the ferrite medium will fuse together at the
heat sites, yada, yada, yada...
It would take a LOT of local heating to change enough of the medium
that is in play during operation to make a difference to said operational
characteristic. Grinding just doesn't apply that kind of heating, and
the makers agree that grinding is the way these things are to be
manipulated.
Does a pot core with rounded corners take a performance hit over the
cheap, easy mold, punched out jobs that have the sharp, squared corners,
or is even that little bit of extra mass "in-play" magnetically speaking
as a function of the whole pot core's characteristic functions?
I say the rounded corner job is fine, if not even better. They cost
more though, and are slightly weaker mechanically.
The 'ceramic' guy might be back too. I said they were not ceramic(s).
They are not. They are "ceramic like" in their manufacturing process.
That is where it stops. Ceramics are not 'machinable'. Ferrites are.
Bill Sloman
> On Sat, 12 Jun 2010 02:05:35 -0700 (PDT),Bill Sloman
>
>
>
> <bill.slo...@ieee.org> wrote:
> >On Jun 12, 1:33 am, John Fields <jfie...@austininstruments.com> wrote:
> >> On Fri, 11 Jun 2010 14:54:12 -0700 (PDT),Bill Sloman
>
> >> <bill.slo...@ieee.org> wrote:
> >> >Learn to write in a way that doesn't make claims that you didn't
> >> >intend.
>
> >> ---
> >> Unnecessarily nasty when, in all fairness, the thread _is_ about
> >> machining ferrite, and the heat he was referring to (which I think
> >> most of the rest of us picked up on) could only have been caused by
> >> the grinding operation.
>
> >Perhaps. But you snipped his " Learn to read, dumbfuck." which - to my
> >mind - does justify a tolerably nasty clsong sentence.
>
> ---
> His: "Learn to read, dumbfuck." had nothing technical to add to the
> discussion, so I snipped it for that reason.
You were complaining that part of my response was "unnecessarily
nasty" which isn't any kind of technical point, and what you snipped
was entirely germane to assessing the level of nastiness that might
have been appropriate.
> More to the point, if what you're saying is true, then faulting him
> for _your_ misinterpretaion of his statement(s) is an error on your
> part.
>
> That is, since the subject of the thread is "ferrite machining?", one
> with a modicum of sense would infer that the heat referred to was
> generated purely by mechanical means and that the Curie temperature of
> the material, at that point was immaterial.
And who did you consult to find out what someone with a modicum of
sense would have thought?
<snipped the rest of John Fields posing as someone with a modicum of
sense>
--
Bill Sloman, Nijmegen
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sat, 12 Jun 2010 09:35:16 -0500, John Fields
>
>
> >That is, since the subject of the thread is "ferrite machining?", one
> >with a modicum of sense would infer that the heat referred to was
> >generated purely by mechanical means and that the Curie temperature of
> >the material, at that point was immaterial.
>
> Jeez, I wish I could expound facts the way you do.
Sadly, he does.
--
Bill Sloman, Nijmegen
Bill Sloman
> On Sat, 12 Jun 2010 08:11:03 -0700, BlindBaby
>
But, granting that the admiration comes fron BlindBaby, not worth
much.
--
Bill Sloman, Nijmegen
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Fri, 11 Jun 2010 19:25:07 -0500, Jim Yanik <jya...@abuse.gov> wrote:
> >Sjouke Burry <burrynulnulf...@ppllaanneett.nnll> wrote in
> >news:4c12c34e$0$14129$703f...@textnews.kpn.nl:
>
> >> Yzordderrex wrote:
> >>> Does anyone know of ferrrite can be turned on a lathe?
>
> >>> I have a short 1" long by 1" dia. rod ( i know, i know, a personal
> >>> problem) and I would like to have a grove machined into it to accept a
> >>> few turns of wire. there will then be a bobbin slipped over that with
> >>> the secondary on it.
>
> >>> I suppose this might be done with some type of grinder as well.
>
> >>> Just curious to know what machining options are available for ferrite.
>
>
> >>> regards,
> >>> Bob
>
> >> Diamond rotating saw disk??
>
> >it's a ceramic;grinding can introduce stress fractures(cracks).
>
> It is closer to an epoxy bound sintered matrix than a ceramic.
> Ceramics get post sintering firings that harden them further.
Regular ferrites aren't resin-bonded. You can get resin-bonded soft
and hard ferrites and, but the resin dilutes the magentic material and
the magnetic performance is consequently poor.
You may have only intended to claim that soft ferrites are relatively
soft as sintered materials go, but to claim that regular ferrites are
expoxy bound sintered matrices is simply wrong.
> Machining with striking tools like a lathe bit or mill head cutting
> flute/tooth will CERTAINLY introduce fractures.
>
> Grinding is the ONLY 'correct' type of machining to remove media from
> them. They are not 'fired' like a ceramic and do not have the hardness
> that a ceramic acquires... AT ALL. They ARE too hard to machine, but
> they are not too hard to grind media from.
Sintering depends on the same process of solid state diffusion that
makes ceramics hard, but managanese-zinc and nickel-zinc ferrites
aren't ceramics -inorganic non-metallic solids - and shouldn't be
expected to have similar properties, or to react to heat treatment in
the same way.
--
Bill Sloman, Nijmegen
MooseFET
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Fri, 11 Jun 2010 20:24:34 -0700 (PDT), MooseFET <kensm...@rahul.net>
> wrote:
>
> >On Jun 12, 1:33 am, Bill Sloman <bill.slo...@ieee.org> wrote:
> >[...]
> >> Wrong. Permeability drops with rising temperature, and leakage flux
> >> rises. Ferrite cores don't have to get very hot before they become
> >> magnetically insignificant. Read the relevant data sheets for the
> >> material used to make your core on the manufactuere's web site.
>
> >This has nothing to do with the reason to watch the temperature rise.
> >It is just plain a mechanical issue. The material is brittle and a
> >bad
> >conductor of heat.
>
> And grinding it doesn't hurt it at all. It got heated when it got
> made. It is a sintered, stamped, baked manufacturing process.
All sintered things are brittle. Watch the temperature.
MooseFET
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kensm...@rahul.net>
> wrote:
>
>
>
> >On Jun 12, 12:07 am, BlindBaby
> ><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> >> On Fri, 11 Jun 2010 08:11:04 -0700, John Larkin
>
> >> >On Fri, 11 Jun 2010 06:41:57 -0700 (PDT), MooseFET
> >> ><kensm...@rahul.net> wrote:
>
> >> >>On Jun 11, 8:42 pm, Yzordderrex <powersupply...@netzero.net> wrote:
> >> >>> Does anyone know of ferrrite can be turned on a lathe?
>
> >> >>> I have a short 1" long by 1" dia. rod ( i know, i know, a personal
> >> >>> problem) and I would like to have a grove machined into it to accept a
> >> >>> few turns of wire. there will then be a bobbin slipped over that with
> >> >>> the secondary on it.
>
> >> >>> I suppose this might be done with some type of grinder as well.
>
> >> >>> Just curious to know what machining options are available for ferrite.
>
> >> >>you would normally do with a lathe in metal, consider a tool
> >> >>post mounted grinder. Watch the temperature rise.
>
> >> >Maybe a dremel with a diamond wheel?
>
> >> >John
>
> >> After the grooves get ground (any cutting attempt will result in
> >> fracture), you need to cover the rod with transformer tape to insulate it
> >> from your primary wire.
>
> >> If you make an open ended core transformer, it will be pretty leaky
> >> unless you use a closed loop core arrangement.
>
> >> You would probably be better off with a pot core.
>
> >> I would use a dremel tool and grinding or cutting (abrasive cutting)
> >> disc attached.
>
> >> If you are making a large groove for a single layer of larger wire the
> >> grooves will allow the wire profile to sit a bit lower.,
>
> >> If you are using fairly small primary wire, you do not need the grooves
> >> at all.
>
> >> Temperature rise? They are not magnets. There are no properties to
> >> lose via introduction of heat.
>
> >The one partedness can be lost through the heat rise at the machined
> >point. They don't conduct heat well and neither does the grinder.
> >I stand by my suggestion that temperature rise be watched.
>
> grinding site?
The problem isn't one of melting together. It is one of the thing
becoming
multiple bits of broken material.
Since the rest was insulting I removed it. The OP wants to cut a
groove into a rod.
MooseFET
> On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kensm...@rahul.net> wrote:
[...]
> Anyway, 150 grit diamond tool rips into the stuff, black dust everywhere,
> easy to fracture pieces off, very harsh if one applies too much pressure.
The problem is mostly the local temperature rise. If you are careful,
you
can cut an O-ring groove into a rod core to seal the place where it
goes
through a wall. Fine work can be done but when making any sort of a
groove a lot of care is needed.
John Fields
<bill....@ieee.org> wrote:
---
Snipped irrelevancies...
---
>And who did you consult to find out what someone with a modicum of
>sense would have thought?
---
Certainly not you!
John Fields
---
Tsk, tsk, problems with English _and_ logic...
BlindBaby
<bill....@ieee.org> wrote:
Sadly, you prove yet again that you are a sub-human, pathetic prick.
BlindBaby
Sadly, you prove yet again that you are a sub-human, pathetic prick.
BlindBaby
<bill....@ieee.org> wrote:
>Regular ferrites aren't resin-bonded. You can get resin-bonded soft
>and hard ferrites and, but the resin dilutes the magentic material and
>the magnetic performance is consequently poor.
Ferrite are specifically formulated to keep the magnetic particles
APART from each other, idiot.
BlindBaby
<bill....@ieee.org> wrote:
>Sintering depends on the same process of solid state diffusion that
>makes ceramics hard, but managanese-zinc and nickel-zinc ferrites
>aren't ceramics -inorganic non-metallic solids - and shouldn't be
>expected to have similar properties, or to react to heat treatment in
>the same way.
They don't, idiot. That is why they are described as being "ceramic
like".
BlindBaby
wrote:
You're an idiot. Your temperature must not have been watched well
enough.
John Fields
---
What a nasty piece of work you are!
Just because you don't get any doesn't mean it's not worthwhile.
BlindBaby
wrote:
>On Jun 12, 8:30 pm, Grant <o...@grrr.id.au> wrote:
Your brain is on overkill, and you can't even get that right.
John Fields
<bill....@ieee.org> wrote:
>On Jun 12, 2:47�am, BlindBaby
><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
>> � It is closer to an epoxy bound sintered matrix than a ceramic.
>> Ceramics get post sintering firings that harden them further.
>
>Regular ferrites aren't resin-bonded.
---
What is it you don't understand about: "closer to?"
>You can get resin-bonded soft
>and hard ferrites and, but the resin dilutes the magentic material and
>the magnetic performance is consequently poor.
---
"hard ferrites and, but"???
"magentic"???
Maybe, in your state of perpetual torpor, you meant:
???
JF
John Fields
---
I don't believe that's right, since at least some (if not most)
sintered metallic parts retain the mechanical properties of their
parent metals or alloys.
For example:
http://www.lm-tarbell.com/machining_sintered_bronze.htm
Take a look at the rejected bearing; if it was brittle the metal
wouldn't have smeared like it did.
BlindBaby
I worked in an auto machine shop years ago and had to fit huge truck
king pins and their steering knuckles together. The final tolerances
were less than 5 ten thousandths of an inch. Those bushings had no
brittleness. I had a bucket of smashed ones, and they make great shims
under a hydraulic press, particularly due to their malleability and
softness. More firm than raw brass, but certainly no rough granularity
to it like bronze. It was a fine matrix.
John Ferrell
<powersu...@netzero.net> wrote:
>Does anyone know of ferrrite can be turned on a lathe?
>
>I have a short 1" long by 1" dia. rod ( i know, i know, a personal
>problem) and I would like to have a grove machined into it to accept a
>few turns of wire. there will then be a bobbin slipped over that with
>the secondary on it.
>
>I suppose this might be done with some type of grinder as well.
>
>Just curious to know what machining options are available for ferrite.
>
>regards,
>Bob
I made a simple fixture to hold a Dremel tool on the toolpost of my
Jet 9X20 Metal lathe. Most of the 9X20's seem to have the same
castings so there are a lot of them around. The cutting tool for this
job would be the same as what I use for e-clips on rod stock: the tiny
abrasive disk that shatters every time you use one hand held. It will
last a while in this application. As for the tool post mount, think
about a piece of angle, wood block & wood screws and hose clamps.
light cuts don't need to be super rigid. A well positioned vacuum
cleaner (use duct tape!) will save a lot on clean up.
John Ferrell W8CCW
Archimedes' Lever
<jferr...@triad.rr.com> wrote:
> the tiny
>abrasive disk that shatters every time you use one hand held.
The fibrous "concrete saw" type disc works better. "dado" two together
for wider cuts.
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sat, 12 Jun 2010 09:18:29 -0700 (PDT),Bill Sloman
>
> >Regular ferrites aren't resin-bonded. You can get resin-bonded soft
> >the magnetic performance is consequently poor.
>
> Ferrite are specifically formulated to keep the magnetic particles
> APART from each other, idiot.
Only in the sense that the crystal structure that you get at the
atomic scale spaces the magnetic nuclei at the right separation from
each other to maximise the kind of interaction that you want.
Resin-bonding couples rather larger groups of atoms. It doesn't have
any effect on the atom-to-atom spacings that dictate the basic
magentic properties of the lumps of ferrite being bonded, but the
space taken up by the resin means that there is less room for ferrite.
--
Bill Sloman, Nijmegen
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sat, 12 Jun 2010 09:18:29 -0700 (PDT),Bill Sloman
>
> >Sintering depends on the same process of solid state diffusion that
> >makes ceramics hard, but managanese-zinc and nickel-zinc ferrites
> >aren't ceramics -inorganic non-metallic solids - and shouldn't be
> >expected to have similar properties, or to react to heat treatment in
> >the same way.
>
> They don't, idiot. That is why they are described as being "ceramic
> like".
But not enough like ceramics for the comparison to be useful? So why
did you bring ceramics into the discussion in the first place?
--
Bill Sloman, Nijmegen
Bill Sloman
> On Sat, 12 Jun 2010 09:18:29 -0700 (PDT),Bill Sloman
>
> >On Jun 12, 2:47 am, BlindBaby
> ><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> >> It is closer to an epoxy bound sintered matrix than a ceramic.
> >> Ceramics get post sintering firings that harden them further.
>
> >Regular ferrites aren't resin-bonded.
>
> ---
> What is it you don't understand about: "closer to?"
BlindBaby was expressing himself with his usual lack of precision.
You've snipped the part of my response that dealt with the other
meaning that he might have had in mind - or more likely you didn't
bother to read past the point at which you could insert your smart-ass
comment, and the snip merely reflects your limited attention span and
your deficiencies in the mental faculties usually mobilised in
interactions between adults.
> >You can get resin-bonded soft
> >and hard ferrites, but the resin dilutes the magnetic material and
> >the magnetic performance is consequently poor.
>
> ---
>
> "hard ferrites and, but"???
>
> "magentic"???
>
> Maybe, in your state of perpetual torpor, you meant:
>
> http://magentic.net/en/
Getting excited about typos again?
--
Bill Sloman, Nijmegen
BlindBaby
That depends on the level of liquefaction introduced.
BlindBaby
I didn't. Someone else did, and they called them ceramic. I corrected
him, and then I referenced that here. IF you had enough brains to
actually have read the entire thread, you might have caught that.
But I fear that you don't catch much.
Shame, that... smallpox or the like comes to mind.
BlindBaby
<bill....@ieee.org> wrote:
>BlindBaby was expressing himself with his usual lack of precision.
Talk about PKB.
BlindBaby
<bill....@ieee.org> wrote:
>your deficiencies
You haven't even read the thread. The deficiencies are all YOURS.
Grant
>On Sat, 12 Jun 2010 22:30:06 +1000, Grant <o...@grrr.id.au> wrote:
>
>>On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kens...@rahul.net> wrote:
>>
>>>On Jun 12, 12:07 am, BlindBaby
>>><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
>>>> On Fri, 11 Jun 2010 08:11:04 -0700, John Larkin
>>>>
>>>>
>>>>
>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>> >On Fri, 11 Jun 2010 06:41:57 -0700 (PDT), MooseFET
>>>> ><kensm...@rahul.net> wrote:
>>>>
>>>> >>On Jun 11, 8:42 pm, Yzordderrex <powersupply...@netzero.net> wrote:
>>>> >>> Does anyone know of ferrrite can be turned on a lathe?
>>>>
>>>> >>> I have a short 1" long by 1" dia. rod ( i know, i know, a personal
>>>> >>> problem) and I would like to have a grove machined into it to accept a
>>>> >>> few turns of wire. there will then be a bobbin slipped over that with
>>>> >>> the secondary on it.
>>>>
>>>> >>> I suppose this might be done with some type of grinder as well.
>>>>
>>>> >>> Just curious to know what machining options are available for ferrite.
>>>>
>>>> >>Grinding is the way to go. If you want to cut something that
>>>> >>you would normally do with a lathe in metal, consider a tool
>>>> >>post mounted grinder. Watch the temperature rise.
>>>>
>>>> >Maybe a dremel with a diamond wheel?
>>>>
>>>> >John
>>>>
>>>> After the grooves get ground (any cutting attempt will result in
>>>> fracture), you need to cover the rod with transformer tape to insulate it
>>>> from your primary wire.
>>>>
>>>> If you make an open ended core transformer, it will be pretty leaky
>>>> unless you use a closed loop core arrangement.
>>>>
>>>> You would probably be better off with a pot core.
>>>>
>>>> I would use a dremel tool and grinding or cutting (abrasive cutting)
>>>> disc attached.
>>>>
>>>> If you are making a large groove for a single layer of larger wire the
>>>> grooves will allow the wire profile to sit a bit lower.,
>>>>
>>>> If you are using fairly small primary wire, you do not need the grooves
>>>> at all.
>>>>
>>>> Temperature rise? They are not magnets. There are no properties to
>>>> lose via introduction of heat.
>>>
>>>The one partedness can be lost through the heat rise at the machined
>>>point. They don't conduct heat well and neither does the grinder.
>>>I stand by my suggestion that temperature rise be watched.
>>
>>I just spent some time with a high speed hobby drill, various grinding
>>attachments and a then piece of ferrite, a figure eight buckle type they
>>wind those mains filters on, the type with sprocket teeth on the coil
>>former so the ferrite is one piece.
>>
>>Anyway, 150 grit diamond tool rips into the stuff, black dust everywhere,
>>easy to fracture pieces off, very harsh if one applies too much pressure.
>>
>>The sanders and other grinders a bit more gentle, most gentle (but slow)
>>was the thin cutoff wheel when use with light pressure and kept moving
>>to avoid localised heating. If I tried too hard to grind one spot, the
>>ferrite would fracture from the hot spot, through several mm of ferrite.
>>
>>Machining ferrite is easy, with a little practice to develop a feel
>>for what is easy, and stuff that is dangerous in the sense of risking
>>fracturing the job.
>>
>>Diamond tools would need to be a lot finer than 150 grit to lessen the
>>impact and give a smoother finish -- easy to control with light pressure
>>and rips out the material quickly.
>>
>>Interesting stuff to play with. And try different tool speeds, the
>>abrasion rate doesn't necessarily go up with speed. Odd?
>>
>>Grant.
>
> Ever seen a pot core pair with mirror polished mating faces?
> They are abrasively finished.
Sure, but with much finer stuff than I have here, unless I go to
wet'n'dry emery paper.
The exercise I tried last night was simply to get a feel for how
the stuff reacts to 'hobby' working, and also to see how easy it
is to fracture that stuff.
Machining a fine groove is difficult because of the need to keep the
tool moving to avoid creating a hot spot that will generate a fracture
somewhat like scratching and tapping glass does. The stuff is very
brittle but still easy to machine with lots of patience and a light
touch.
I've broken many transformer cores trying to recover them from busted
PC power supplies -- haven't hit on a safe way to get them apart when
the things have so well been vacuum with varnish or glued. One pair
from maybe couple dozen attempts, but I wrecked the former -- found a
transformer not well varnished that time.
My interest in grinding ferrite stems from seeing an article on a high
power transformer where the author ground the centre stem down to half
diameter, instead of using a gapped core. I forget now just why this
was considered better than an air gap.
So many here prefer arguing instead of simple discovery ;) Suck it and
see.
Grant.
--
http://bugs.id.au/
Grant
Yes, I discovered that last night, localised heating trying to get a
narrow cut will easily start a fracture, there's no great pressure or
vibration evident to cause the fracture, it's the localised heat.
Obvious, when one works with the material. Need to keep the tool
moving to distribute the heat loading.
And the generated heat is very localised, I was holding the ferrite
in my hand, and the stuff did not warm up after being ground.
Ferrite not a good heat conductor. I've also fractured ferrites by
heating with a hot air gun trying to soften the varnish and/or glue
to separate and recover transformer parts. same story, localised
heat will fracture ferrite material.
Grant.
--
http://bugs.id.au/
Grant
>On Fri, 11 Jun 2010 05:42:19 -0700 (PDT), Yzordderrex
><powersu...@netzero.net> wrote:
>
>>Does anyone know of ferrrite can be turned on a lathe?
>>
>>I have a short 1" long by 1" dia. rod ( i know, i know, a personal
>>problem) and I would like to have a grove machined into it to accept a
>>few turns of wire. there will then be a bobbin slipped over that with
>>the secondary on it.
>>
>>I suppose this might be done with some type of grinder as well.
>>
>>Just curious to know what machining options are available for ferrite.
>>
>>regards,
>>Bob
>I made a simple fixture to hold a Dremel tool on the toolpost of my
>Jet 9X20 Metal lathe. Most of the 9X20's seem to have the same
>castings so there are a lot of them around. The cutting tool for this
>job would be the same as what I use for e-clips on rod stock: the tiny
>abrasive disk that shatters every time you use one hand held.
The 22mm red and black ones? I break them not in use, but in careless
handling of the tool! Only had high speed thingy for a few weeks, it's
been great.
> It will
>last a while in this application. As for the tool post mount, think
>about a piece of angle, wood block & wood screws and hose clamps.
>light cuts don't need to be super rigid. A well positioned vacuum
>cleaner (use duct tape!) will save a lot on clean up.
Yes, I need to arrange some dust vacuum here, but it's more difficult
for handheld -- I'm dreaming up some sort of blower + vacuum arrangement
that could help direct the dust to a vacuum. Or maybe a high volume,
low vacuum fan and duct arrangement so some sort of filter; like I've
seen in some photos of handheld machining.
The 150 grit diamond tool tips in the cheapy abrasive sets seem too
harsh for ferrite, they jar and shatter, but diamond does cut the
stuff quite well. So I imagine finer grit diamond tools would be
good to try.
The miniature thin cutting off wheels are much slower cutting ferrite,
but very little vibration if you properly mount and dress them before
use.
Grant.
--
http://bugs.id.au/
Archimedes' Lever
>Sure, but with much finer stuff than I have here, unless I go to
>wet'n'dry emery paper.
Jeweler's rouge from the hobby shop. It's a rock polishing tool.
Pot cores are like rocks.
Folks been doin' it that way for decades. Many decades.
Archimedes' Lever
>Yes, I discovered that last night, localised heating trying to get a
>narrow cut will easily start a fracture, there's no great pressure or
>vibration evident to cause the fracture, it's the localised heat.
>Obvious, when one works with the material. Need to keep the tool
>moving to distribute the heat loading.
If you guys are overheating ferrites, I'd say that your technique
suffers from more then tool speed issues.
Archimedes' Lever
> same story, localised
>heat will fracture ferrite material.
Even fast rise in an oven will do it, so even full body heat will do
it, if the rise rate is too high.
In fact, that is where you have to most watch out for it. Reflow and
wave pre-heat profiles.
This is also why a lot of transformers and such which are ferrite based
get attached by hand post automatic process.
But dremeling is not going to do it unless you are just plain dumb
about it.
Archimedes' Lever
>The 150 grit diamond tool tips in the cheapy abrasive sets seem too
>harsh for ferrite, they jar and shatter, but diamond does cut the
>stuff quite well. So I imagine finer grit diamond tools would be
>good to try.
>
>The miniature thin cutting off wheels are much slower cutting ferrite,
>but very little vibration if you properly mount and dress them before
>use.
A nice, fine set of jeweler's file also cut meat away pretty well. You
just have to watch that you are not too aggressive with the stroke speed
and pressure. It is, in fact, a very nice way to do some tasks one might
find a need for in ferrites. I used a flat file to shave pot core faces
pretty often, since the mini pot cores fit onto the whole file flat. Or
I would use the file as the base/face for my abrasive paper or cloth.
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sat, 12 Jun 2010 16:30:38 -0700 (PDT),Bill Sloman
>
>
>
> <bill.slo...@ieee.org> wrote:
> >On Jun 12, 7:19 pm, BlindBaby
> ><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> >> On Sat, 12 Jun 2010 09:18:29 -0700 (PDT),Bill Sloman
>
> >> <bill.slo...@ieee.org> wrote:
> >> >Sintering depends on the same process of solid state diffusion that
> >> >makes ceramics hard, but managanese-zinc and nickel-zinc ferrites
> >> >aren't ceramics -inorganic non-metallic solids - and shouldn't be
> >> >expected to have similar properties, or to react to heat treatment in
> >> >the same way.
>
> >> They don't, idiot. That is why they are described as being "ceramic
> >> like".
>
> >But not enough like ceramics for the comparison to be useful? So why
> >did you bring ceramics into the discussion in the first place?
>
> I didn't. Someone else did, and they called them ceramic. I corrected
> him, and then I referenced that here. IF you had enough brains to
> actually have read the entire thread, you might have caught that.
>
> But I fear that you don't catch much.
There's not a lot in this thread to appreciate.
> Shame, that... smallpox or the like comes to mind.
In so far as small-pox doesn't exist - as an infectious disease - any
more, the fact that it comes to your mind is illustrative of your
feeble grasp of reality.
http://en.wikipedia.org/wiki/Smallpox
So far, it is the only infectious disease of humans to have been
eradicated. Polio is next on the list, but we're not quite there yet.
--
Bill Sloman, Nijmegen
BlindBaby
<bill....@ieee.org> wrote:
>In so far as small-pox doesn't exist - as an infectious disease - any
>more, the fact that it comes to your mind is illustrative of your
>feeble grasp of reality.
Actually, due to terrorist strains, it may make a comeback, and I know
far more about it than you do as I never received a vaccination, and I
was born in 1960.
Had I gotten one, I would have contracted the disease (a deadly version
of cowpox). My brother did not get one either as he would have given it
to me. I had a condition at the time known as spots.
So I knew more about the disease at age five than you do now.
John Ferrell
If it is small enough to do the job it is a better choice. I don't
throw the away until they are dime size!
John Ferrell W8CCW
MooseFET
> On Sat, 12 Jun 2010 09:20:37 -0700 (PDT), MooseFET
>
>
>
> >On Jun 12, 11:48 am, BlindBaby
> ><BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> >> On Fri, 11 Jun 2010 20:24:34 -0700 (PDT), MooseFET <kensm...@rahul.net>
> >> wrote:
>
> >> >On Jun 12, 1:33 am, Bill Sloman <bill.slo...@ieee.org> wrote:
> >> >[...]
> >> >> Wrong. Permeability drops with rising temperature, and leakage flux
> >> >> rises. Ferrite cores don't have to get very hot before they become
> >> >> magnetically insignificant. Read the relevant data sheets for the
> >> >> material used to make your core on the manufactuere's web site.
>
> >> >This has nothing to do with the reason to watch the temperature rise.
> >> >It is just plain a mechanical issue. The material is brittle and a
> >> >bad
> >> >conductor of heat.
>
> >> And grinding it doesn't hurt it at all. It got heated when it got
> >> made. It is a sintered, stamped, baked manufacturing process.
>
> >All sintered things are brittle. Watch the temperature.
>
> ---
> I don't believe that's right, since at least some (if not most)
> sintered metallic parts retain the mechanical properties of their
> parent metals or alloys.
The cores I have experience with are metal oxides not metals.
They are brittle.
MooseFET
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sat, 12 Jun 2010 09:29:32 -0700 (PDT), MooseFET <kensm...@rahul.net>
I stand by my warning. What you claim doesn't matter because
I know I will be shown to be correct.
John Ferrell
I prefer abrasives whenever possible for cutting. They simply costy a
lot less.
I sometimes need a special dust collector for a project. It does not
have to be fancy. Think shoe box with perf board duct taped to to the
top, vacuum cleaner hose in the side with a rag for a seal. All vacuum
cleaners need to move a lot of air for cooling.
John Ferrell W8CCW
MooseFET
> On Sat, 12 Jun 2010 09:29:32 -0700 (PDT), MooseFET <kensm...@rahul.net> wrote:
> >On Jun 12, 8:30 pm, Grant <o...@grrr.id.au> wrote:
> >> On Fri, 11 Jun 2010 20:20:54 -0700 (PDT), MooseFET <kensm...@rahul.net> wrote:
> >[...]
> >> Anyway, 150 grit diamond tool rips into the stuff, black dust everywhere,
> >> easy to fracture pieces off, very harsh if one applies too much pressure.
>
> >The problem is mostly the local temperature rise. If you are careful,
> >you
> >can cut an O-ring groove into a rod core to seal the place where it
> >goes
> >through a wall. Fine work can be done but when making any sort of a
> >groove a lot of care is needed.
>
> Yes, I discovered that last night, localised heating trying to get a
> narrow cut will easily start a fracture, there's no great pressure or
> vibration evident to cause the fracture, it's the localised heat.
> Obvious, when one works with the material. Need to keep the tool
> moving to distribute the heat loading.
If you want accurate machining of a groove, you need a small grinder
mounted to a lathe. Doing it by hand is ok if you just need to make a
small notch or the like.
> And the generated heat is very localised, I was holding the ferrite
> in my hand, and the stuff did not warm up after being ground.
>
> Ferrite not a good heat conductor. I've also fractured ferrites by
> heating with a hot air gun trying to soften the varnish and/or glue
> to separate and recover transformer parts. same story, localised
> heat will fracture ferrite material.
I have used a heat gun to get glue off cores. I think the trick is to
have a big heat gun so that the whole core is warmed up.
Bill Sloman
<BlindMelonChit...@wellnevergetthatonethealbumcover.org> wrote:
> On Sun, 13 Jun 2010 00:51:50 -0700 (PDT), Bill Sloman
>
Or so you seem to think. I'm old enough to have been innoculated
against small-pox, and I know enough to have heard about Jenner and
where the term vaccination came from - it is a reference to the cow-
pox which you claim includes a "deadly strain".
http://en.wikipedia.org/wiki/Edward_Jenner
If you had got all that on board at the age of five, you'd have been a
bright kid. The fact that you don't seem to have retained much of it
as an adult does suggest that you were dropped on your head sometime
in the intervening period.
--
Bill Sloman, Nijmegen
John Fields
<kens...@rahul.net> wrote:
>On Jun 13, 1:40 am, John Fields <jfie...@austininstruments.com> wrote:
>> On Sat, 12 Jun 2010 09:20:37 -0700 (PDT), MooseFET
>> >All sintered things are brittle. Watch the temperature.
>>
>> ---
>> I don't believe that's right, since at least some (if not most)
>> sintered metallic parts retain the mechanical properties of their
>> parent metals or alloys.
>
>The cores I have experience with are metal oxides not metals.
>They are brittle.
---
Ah, but that's a subset of "all sintered things", yes?
Archimedes' Lever
<jferr...@triad.rr.com> wrote:
>On Sat, 12 Jun 2010 13:43:58 -0700, Archimedes' Lever
><OneBi...@InfiniteSeries.Org> wrote:
>
>>On Sat, 12 Jun 2010 15:59:17 -0400, John Ferrell
>><jferr...@triad.rr.com> wrote:
>>
>>> the tiny
>>>abrasive disk that shatters every time you use one hand held.
>>
>> The fibrous "concrete saw" type disc works better. "dado" two together
>>for wider cuts.
>If it is small enough to do the job it is a better choice. I don't
>throw the away until they are dime size!
>John Ferrell W8CCW
They are great for trimming way material of just about any strata, and
they can be used for all types (methods) of said removal.
I buy 'em buy the five pack, I think.
Great for trace cutting. Great for PCB 'slotting' for HV
isolation/creepage, etc.
There are so many places where it does the job, and leaves little
abrasive debris behind in doing it.
I have used those little cut-off discs for soooo many things.
BlindBaby
wrote:
>On Jun 13, 1:40 am, John Fields <jfie...@austininstruments.com> wrote:
There are two types of ferrites. Hard ferrites will retain
magnetization effects. Soft ferrites will not. Soft ferrite ARE
'machinable', typically though only by way of grinding.
Manufacturing processes for each type are similar, but do differ from
maker to maker. There are many 'styles' however, that are manufactured
in a common way so that designers can choose form more than one producer
for their raw goods, and get like performance expectations. Common sense
again... duh.
Lots of cutting edge hybrid stuff out there though. That's also how we
got advanced magnetics science over the last 60 years too. The colleges
toyed with materials, and the factories made the goods to be tested to
prove the science.
BlindBaby
wrote:
>On Jun 13, 1:21 am, BlindBaby
The temp rise is not what you have to watch for. It is the RATE of
temp rise, and that rate is not going to be exceeded by dremeling, unless
you are a total idiot when you get the dremel in your hand, in which
case, you should be on a different career path, such as street sweeping.
Archimedes' Lever
wrote:
>If you want accurate machining of a groove, you need a small grinder
>mounted to a lathe. Doing it by hand is ok if you just need to make a
>small notch or the like.
>
Actually, a bobbin winder is the right tool. A lathe, even on its
slowest speed, is far to fast.
John Larkin
There are some fairly soft sintered things, like sintered brass gas
diffuser things. And sintered plastics.
John
Archimedes' Lever
wrote:
>I have used a heat gun to get glue off cores. I think the trick is to
>have a big heat gun so that the whole core is warmed up.
More proof that you do not know what is up.
The heat gun will cause the cracks you were so worried about in your
dis-informing earlier horseshit post.
Yo have to raise the temp SLOWLY. That means a slow rise, like that of
an oven.
The heat gun will ALWAYS exceed the temp rise rate maximum specified by
the maker, which is typically 10C per minute.
The way to attack epoxy links on ferrite bobbins is with a soldering
iron, and an old, no longer used for solder tip. You use the tip to
'melt' it way through the 'glue links' between segments. Most epoxies
'soften' at elevated temperatures, but that temp is pretty high.
Using a heat gun to bring the thing up is dumb because you bring it up
too fast. Better to bring it up to 350F in an oven and THEN do the last
thermal transition with added heat. Trying to do the entire transition
with a hot air flow is just stupid.
The really sad thing is that YOU KNOW THAT I AM RIGHT, asshole.
Looks like 'Kenny' ain't all he thinks he is.
dagmarg...@yahoo.com
Flooding with work with coolant would help. Keeps the dust down too.
But yeah, it's messy.
--
Cheers,
James Arthur
Archimedes' Lever
<jfi...@austininstruments.com> wrote:
He wants to blow flame (hot air) over them now too.
Archimedes' Lever
The filter elements are sintered with things like 'fine silt clay', and
then the clay gets washed out after the sintering. leaving the porous
medium behind. They can be brittle or be such that further press
forming, etc. operations can be performed on them.
There is 'nearly dry' concrete mix that gets applied and formed on the
ground, and after drying are very very porous, because they did no
vibrational settling of the dry mix. One ends up with a driveway that
never gets a rain puddle on it. It absorbs hundreds of gallons of water,
and transfers it beneath the slab for storage or transport to drainage.