EDM cut rifle chamber, curiosity or the future?
Clark Magnuson
--
Accidental creation should not be taught as a fact.
Intelligent creation should not be banned from teachings as
unconstitutional.
Tom Wait
"Clark Magnuson" <c.mag...@comcast.net> wrote in message
news:BZ-dnRodc9kq_PTe...@comcast.com...
> http://www.6mmbr.com/gunweek055.html
Interesting gun. I'll throw away my reamers when this break action
conistently beats the Krieger barreled Stolles on the bench. BTW I just
rebarreled my FN target Mauser with a Krieger. 6mm 8" twist. 243 Winchester.
I broke it in with some factory loads, now starts load development. I've got
some 105 Berger VLD's and Norma brass to put together tomorrow. Then off to
the range in the PM.
Dave Hinz
>
> "Clark Magnuson" <c.mag...@comcast.net> wrote in message
> news:BZ-dnRodc9kq_PTe...@comcast.com...
>> http://www.6mmbr.com/gunweek055.html
>
> Interesting gun. I'll throw away my reamers when this break action
> conistently beats the Krieger barreled Stolles on the bench.
heh. Couple of years ago, a coworker of mine invited me to see her
friend's metalshop, because she knew I'd be interested. I walked in,
and the machinery was unmistakable.
The boss came up to meet me, and asked if I had any questions.
(rifling lathes were all I could see). My response was something along
the lines of "Well, at that twist rate, I'd expect you're making .223,
and since I know Boots (Obermeyer), you must be Mr. Krieger. I have one
of your barrels on my M1-A." He gave me a great tour, answered some
questions, and it was really nice to know that a guy who makes quality
product also happens to be a nice guy.
> BTW I just
> rebarreled my FN target Mauser with a Krieger. 6mm 8" twist. 243 Winchester.
> I broke it in with some factory loads, now starts load development. I've got
> some 105 Berger VLD's and Norma brass to put together tomorrow. Then off to
> the range in the PM.
He does nice work. Up to you to use it to potential...
Tom Wait
"Dave Hinz" <Dave...@spamcop.net> wrote
Snip
> He does nice work. Up to you to use it to potential...
>
know I can---- Actually I have. Bill Atkinson taught me how to chamber
bench guns and I built a bunch. One was for Walt Berger which he shot to win
some tinware at an international match in Europe around 1984. The FN action
I'm using used to have a factory 22-250 Remington barrel on it and would
shoot 1/4 min. with 40 gr. bullets. It wouldn't do squat with heavier stuff
so I bought the 8" twist 6mm barrrel and decided to use the gun for deer
sniping. That's why I built a 243 Winny. I know the action works, so I'm
looking for some great things from this combo.
Tom
T.Alan Kraus
> BTW I just
> rebarreled my FN target Mauser with a Krieger. 6mm 8" twist. 243 Winchester.
>
That is a fast twist, my fastest in .243 is 1 in 9. Up to what weight
bullet can you stabilize?
cheers
T.Alan
Tom Wait
"T.Alan Kraus" <soun...@sonic.net> wrote in message
news:i0saf.1980$te3....@typhoon.sonic.net...
It should stabilize any bullet made. I think ther are 115 gr. available from
Berger. I'm thinking looooong range plinking here. I'm curious to see if a
55 gr. bullet would fly apart at 4000 fps.
Tom
T.Alan Kraus
You should be able to reach out with a 115 gr. no problem.
cheers
T.Alan
Tom Wait
> The Sierra Blitzking in 55 gr. works well for me in my 1 in 9.
> You should be able to reach out with a 115 gr. no problem.
What powder and load do you favor?
Tom
Clif Holland
Just experience with a 22/250.
--
Clif Holland KA5IPF
www.avvid.com
"Tom Wait" <tomwait30...@sbcglobal.net> wrote in message
news:I9Paf.3789$Lv....@newssvr23.news.prodigy.net...
T.Alan Kraus
> The Blitzking at about 4000 fps turns into a cloud of dust around 50 yds.
> Just experience with a 22/250.
>
rate. I like the Sierra 52 gr. HPBT matchking and the 60 gr. Sierra
Varminter both at about 3500 ft/sec. I guess that is not full speed but
I like my barrels to last a bit more and seem to get my top accuracy there.
Tom Wait wrote:
>What powder and load do you favor?
>Tom
>
I get nice results with 41.2 gr. IMR 4895 and a little more speed but
more spread with 49.4 gr of W 760. The speeds are around 3800 ft/sec.
cheers
T.Alan
Ed Huntress
"Clark Magnuson" <c.mag...@comcast.net> wrote in message
news:BZ-dnRodc9kq_PTe...@comcast.com...
> http://www.6mmbr.com/gunweek055.html
Using EDM to cut rifling is at least 30 years old, although I don't know if
it was ever used in any kind of production (ECM has been used to rifle
barrels for longer than EDM, and it's been used in production). However, I
hadn't heard of using it to cut chambers. I'd like to know what the "patent"
is about.
The description of EDM in that article is about half right.
--
Ed Huntress
Clark Magnuson
>
> Using EDM to cut rifling is at least 30 years old, although I don't know if
> it was ever used in any kind of production (ECM has been used to rifle
> barrels for longer than EDM, and it's been used in production). However, I
> hadn't heard of using it to cut chambers. I'd like to know what the "patent"
> is about.
>
> The description of EDM in that article is about half right.
>
> --
> Ed Huntress
>
>
Ed,
What is right and what is not right in that article?
Clark
D Murphy
news:n38bf.746$rc7...@fe12.lga:
>
> "Clark Magnuson" <c.mag...@comcast.net> wrote in message
> news:BZ-dnRodc9kq_PTe...@comcast.com...
>> http://www.6mmbr.com/gunweek055.html
>
> Using EDM to cut rifling is at least 30 years old, although I don't
> know if it was ever used in any kind of production (ECM has been used
> to rifle barrels for longer than EDM, and it's been used in
> production). However, I hadn't heard of using it to cut chambers. I'd
> like to know what the "patent" is about.
Hey Ed, good to see you posting a bit again. The patent is here -
I sure don't see why they were issued a patent.
>
> The description of EDM in that article is about half right.
I'd have to agree with you there but maybe they were just trying to keep it
simple.
--
Dan
Gunner
wrote:
>The Blitzking at about 4000 fps turns into a cloud of dust around 50 yds.
>Just experience with a 22/250.
Ayup. The old XPs did the same at 3500
Gunner
Confronting Liberals with the facts of reality is very much akin to
clubbing baby seals. It gets boring after a while, but because Liberals are
so stupid it is easy work." Steven M. Barry
Ed Huntress
The general description is pretty good, but there are some important things
missing, and some errors. The errors:
"The spark heats the grains and structure of the chamber wall beyond their
critical temp in the gap..."
Heating beyond the critical temperature is not the point. Heating beyond the
MELTING temperature is the point. EDM melts the surface of the metal.
"The removed metal is then carried away as smoke within a dielectric
insulating fluid..."
The smoke is not from the metal. It's from burned dielectric fluid. The
metal is melted and expulsed from the parent metal by vaporization and
cavitation. The molten metal forms little balls (interestingly, most of them
are hollow) that are then carried away by the dielectric.
"Coolant is provided to insulate the cut from the muzzle end of the barrel
as the EDM..."
I don't know what he's talking about here, and the sentence was
inadvertently truncated. He may mean that the dielectric is pumped in from
the muzzle end, which would be the best way to do it. In any case, if he's
still talking about EDM, it isn't "coolant." It's dielectric fluid. It does
cool, but, again, that's not the reason it's there.
Here's something that isn't in the article, but it should be. They talk
about the recast layer of 0.0001", and about lapping it off. That's all well
and good. If the barrel is made of, say, 4140, the recast layer is going to
be harder than a witch's heart, and just as brittle. Or, maybe not, if some
of the latest fine-finishing circuitry is used. But it probably will be. And
it probably will have microcracks in it. Possibly not, but probably so. If
the EDM is more than a decade old, most likely so.
The problem is that the microcracks may extend well below the recast layer,
into the heat-affected zone (HAZ) and even into the parent metal. Avoiding
that is a matter of having good knowledge of the process and good knowledge
of the way to avoid it -- if you can -- with your particular EDM. This
subject is a critical one with guns and it requires some long talks with the
top engineers at your EDM company, and probably some further research.
As of 25 years ago, the mil spec for military gun manufacture specifically
disallowed any use of EDM, for that reason. I researched the subject myself.
A gunsmith who wanted to use EDM for custom chambering was corresponding
with me about it (I was EDM editor at _American Machinist_ at the time), and
we both got scared off by what we learned. Later, in the early '90s, I had
some discussion with Greg Langenhorst at Mitsubishi about their new
ultra-fine-finish circuitry and it sounded to me like they had the problem
cured.
All this being said, the 'smith who's doing this work sounds like he knows
his stuff, whether or not he knows the underlying physics. The T/C is a
pretty strong affair; 4140 (if that's what it is) is pretty forgiving; and
the whole thing is a matter of being very cautious, to begin with. I was
very interested at the time in using wire EDM to hake the rectangular hole
in a falling-block receiver, and I had worked out what I considered to be a
safe procedure, lapping out 0.004" per side after EDMing. But I never had
one made, so that was the end of it for me.
It does sound like he has something very good going here, and EDM is going
to find its way into some kind of precision gun manufacture, if it hasn't
already. You just have to be aware of what's going on (melting versus
"burning," for example), and you have to dig into it pretty deeply before
taking the leap. In other words, don't try this at home until you really
know what's what.
--
Ed Huntress
Ed Huntress
news:Xns9706701D5C7...@130.133.1.4...
> "Ed Huntress" <hunt...@optonline.net> wrote in
> news:n38bf.746$rc7...@fe12.lga:
>
> >
> > "Clark Magnuson" <c.mag...@comcast.net> wrote in message
> > news:BZ-dnRodc9kq_PTe...@comcast.com...
> >> http://www.6mmbr.com/gunweek055.html
> >
> > Using EDM to cut rifling is at least 30 years old, although I don't
> > know if it was ever used in any kind of production (ECM has been used
> > to rifle barrels for longer than EDM, and it's been used in
> > production). However, I hadn't heard of using it to cut chambers. I'd
> > like to know what the "patent" is about.
>
> Hey Ed, good to see you posting a bit again. The patent is here -
>
> http://tinyurl.com/98aqk
>
> I sure don't see why they were issued a patent.
Hoho! If that's worth a patent, then every application for EDM is worth a
patent. I'll bet that one would fall flat on its face if it was ever
challenged in court.
Thanks for the welcome, Dan. I had a little spare time this weekend. It's
just about gone. <g>
--
Ed Huntress
Tom Quackenbush
<huge snip>
Nice to see you again, Ed. Hope things are well with you.
Nice post, too.
R,
Tom Q.
--
Remove bogusinfo to reply.
D Murphy
@fe09.lga:
> Hoho! If that's worth a patent, then every application for EDM is worth a
> patent. I'll bet that one would fall flat on its face if it was ever
> challenged in court.
My thoughts exactly.
>
> Thanks for the welcome, Dan. I had a little spare time this weekend. It's
> just about gone. <g>
Good to see you around. I wish you had stopped into amc, there is a thread
about Liquidmetal (amorphous metal, metal glass) that I'm betting you might
know a little bit about.
--
Dan
Ed Huntress
Historical information only. I wrote some news items and I think a feature
about it...in 1980. <g>
It's neat stuff. Strong like bull. Ductile. Extremely low magnetic
hysteresis.
--
Ed Huntress
D Murphy
>> Good to see you around. I wish you had stopped into amc, there is a
>> thread about Liquidmetal (amorphous metal, metal glass) that I'm
>> betting you
> might
>> know a little bit about.
>
> Historical information only. I wrote some news items and I think a
> feature about it...in 1980. <g>
>
> It's neat stuff. Strong like bull. Ductile. Extremely low magnetic
> hysteresis.
There are some new developments. It used to be that it was only practical
to manufacture in thin films or thin cross sections. Now there are some new
alloys that can be molded like plastic or more accurately die cast at low
temp. It seems they can make a much larger part. One dimension has to stay
under 4 inches otherwise current capabilities can't control the cooling
properly and it turns into ordinary metal. It's claimed to be stronger and
lighter than tool steel.
--
Dan
Ed Huntress
> "Ed Huntress" <hunt...@optonline.net> wrote in
> news:uBAbf.60079$rE2....@fe10.lga:
>
> >> Good to see you around. I wish you had stopped into amc, there is a
> >> thread about Liquidmetal (amorphous metal, metal glass) that I'm
> >> betting you
> > might
> >> know a little bit about.
> >
> > Historical information only. I wrote some news items and I think a
> > feature about it...in 1980. <g>
> >
> > It's neat stuff. Strong like bull. Ductile. Extremely low magnetic
> > hysteresis.
>
> There are some new developments. It used to be that it was only practical
> to manufacture in thin films or thin cross sections.
They also were making amorphous powder a few years ago, which was
consolidated into tool-steel blocks with HIP. The result was about halfway
between amorphous metal and conventional grain structure, with properties
also halfway between.
> Now there are some new
> alloys that can be molded like plastic or more accurately die cast at low
> temp. It seems they can make a much larger part. One dimension has to stay
> under 4 inches otherwise current capabilities can't control the cooling
> properly and it turns into ordinary metal. It's claimed to be stronger and
> lighter than tool steel.
That's really interesting. Researchers out west somewhere (Univ. of Utah?)
were working on achieving amorphous structures by ultra-precision alloying,
as of three years ago. Maybe this is where it's led.
Anyway, I wouldn't have had anything current to contribute to that
discussion. It sounds like an important subject that's worth looking into.
--
Ed Huntress
Ed Huntress
news:Rjwbf.1311$ZA3.2...@monger.newsread.com...
> Ed Huntress wrote:
> <huge snip>
>
> Nice to see you again, Ed. Hope things are well with you.
>
> Nice post, too.
Well thanks, Tom. Yes, things are well at this end. 'Wishing the same for
you.
I can't seem to get away from EDM. It crops up every once in a while by
surprise, like a recessive gene. <g>
--
Ed Huntress