"buying a lathe" aftershocks
brownnsharp
what measurement criteria you folks would place on lathe and collet
characteristics to be good, acceptable, or bad.
If the Peerless collets are bad, then the Peerless lathe must be bad.
(?). I have found that the fit of the collets at the back of the
collet are important to minimizing runout errors. My Peerless collets
are more consistent than my boley collets in this respect, but I am
far from having a giant collection of collets to compare. The runout
of my Peerless lathe, measured at the collet closing surface, is
minute, probably less than .0002. I would think a ball bearing lathe
would be easier to make accurate than trying to cut cone bearings,
and fitted bushings.. but I admit that I regard people who build
really accurate machine tools as magicians and sorcerers anyway.
The Baron@flash.net
information gathered was that Peerless collets fit a Peerless lathe better
than they would fit in a Boley and Boley collets fit Boley better than
Peerless etc. Perhaps some of the problems people have is mismatched
collets. I will admit that it is most difficult to find a complete set of
any one brand.
I use a watchmakers lathe and collets for clock repair. It is very rare
not to find one that is unusable. Many look like crap but that does not
usually affect accuracy. I find more problems with bad collets than bad
lathes. I know CMW/CMC that would rather drive out the pin in their lathe
headstock than buy another collet.
If you are a watchmaker and daily re-pivot the balance staffs of 26/0
watches then you probably need a better name brand lathe(or at least think
you do). Lathes like Levin, Derbyshire etc. are the upper end lathes.
Most watchmaker that I know don't have an upper end lathe, mostly collectors
have them now.
I know several hobbyist watchmakers that own 4 or more lathes and do not
feel they are ''collecting'' them.
Most of the lathes out there are at least 50 to 75 years old.
"brownnsharp" <ghir...@wt.net> wrote in message
news:eec6920c.02030...@posting.google.com...
Scott A. Ekleberry
to sell all my Moseley collets when I bought my better lathe. I do have
lower grade collets (such as Peerless), but I am slowly replacing them all
with Levin or Shaublin collets. The Baron is right though, a Levin collet
can be crap just as easy as a Peerless depending on how it has been used and
abused (almost no one buys new Levin WW collets, they are $125 each!!!)
As to lathes> Whitcomb lathes are good, but don't have a collet holding
tailstock. Levin and Paulson/Boley-Leinen ball-bearing lathes are great, if
the bearings are good. Thing about ball bearing lathes is if they sit long
enough without use, the ball bearings can actually develop flat spots (I
learned this at AWI)!! The thing that is better about a ball bearing lathe
isn't that they are more accurate, but that they can run a higher speeds for
a longer period of time.
The main thing about Boley-Leinen/Paulson lathes is that the tailstock off
of one will line up PERFECTLY with the headstock off another (try that with
a Levin), they were made to that high of a standard. I had a G. Boley lathe
before I bought my Paulson and it blows the G. Boley away! I gave $525 for
my Paulson on e-Bay, and that included the original cross-slide and collet
holding tailstock. My instructor from AWI owns 2 Boley-Leinen lathes (one
ball bearing and one regular), and he swears by them. If you don't intend to
make balance staffs for watches, then no, you don't need such a high grade
lathe. To be honest, unless you are restoring watches (such as high grade
Swiss, English, or really OLD American), then you aren't going to have to
make many staffs.
NOW, if you want to make staffs, you can save time and $ by buying one of
these high grade lathes. Reason?? You can turn the whole staff in the lathe
at once, then use a Jacot lathe to finish the pivots to size, thereby
skipping the step of turning between centers (for which you need a set of
"TURNS", another $500 investment, not to mention the "dogs" to put on the
staff to turn it in the turns, you don't even want to know what a set of
those cost). I know some CMW's that make staffs this way. BUT YOU MUST HAVE
GOOD COLLETS!!!!
Whatever lathe you buy, just make sure it is a WW pattern (these are a hell
of a lot more accurate!!)! Also, if you are buying a Levin or other high $
lathe, get a GUARANTEE (so you can send it back if the headstock/tailstock
don't match, or bearings are bad, etc.)!!!
Also, get a DC MOTOR. The reason being that you can run the thing almost to
a stop and it will still have the same TORQUE as if it were wide-open, not
so with an AC motor. Yes this is going to cost you, about $250 for the motor
and converter board to run it, but you'll only buy it once.
--
Scott A. Ekleberry
It's About Time!
A full service watch repair shop!
www.itsabouttimeonline.com
SAE...@WOH.RR.COM
"brownnsharp" <ghir...@wt.net> wrote in message
news:eec6920c.02030...@posting.google.com...
Chuck Harris
-----------------------------------------------
Peerless lathes are just fine. They make balance staffs just fine.
They turn off hubs on 26/0 watches just fine. Scott was told he
shouldn't like them, so he doesn't like them! That is fine too!
It doesn't mean that you shouldn't like them. I like mine... just fine.
(do I get the record for using "fine" in a paragraph? Ok, fine!)
Most lathe manufacturers of the era married a headstock with a bed and
a tailstock. They put the same serial number on each part; as they
belonged to each other. They then clamped the bed in a boring machine, and
bored the hole for the headstock, and tailstock. If you notice, all of the
WW lathes have a center point on the ends of the bed. This was used to align
the bed, headstock and tailstock to the center boring machine. Similarly, the
spindles were ground using their bearing surfaces, so they too must be perfect.
As long as you use the correctly fitted headstock/bed/tailstock, and the bed
mating surfaces are not worn out, the alignment will be perfect! Trade them
with other lathe's, and you are probably out of luck.
Some manufacturers, notably G. Boley, and Boley/Leinen (they are different,
you know!) wanted to push the envelope of manufacturing of the day. They
built all the headstocks to a headstock jig, all the beds to a bed jig, and
all the tailstocks to a tailstock jig. This is nice and VERY difficult, but when
done to perfection (it never is) will result in interchangeable assemblies.
So, as Scott says, any Boley/Leinen headstock will fit any Boley/Leinen tailstock,
and any Boley/Leinen bed. Big deal! I have never had the urge to play mix and
match. You shouldn't either.
So, what you should ask, if you are buying a Peerless Marshall lathe, is if the
serial numbers match. They MUST! If they don't, PASS!
Then you need to know the condition of the spindle bearings, and on the bed
surface. If you see a lathe being sold with a grinding wheel fixture, you
should consider passing. The grit gets everywhere, and will very quickly ruin a perfectly
good lathe. After dry grinding you MUST completely disassemble your cone bearings
and clean them. (as well as the tailstock and steady rest.) For <insert favorite
deity here> sake get a grinder! Keep it away from your lathe. They are dirt cheap.
As to bearings. Pass on any 8mm WW lathe that has a ball bearing headstock. They
are inferior to either hard of soft cone bearings for watch work. The individual
balls are nearly perfect, but the imperfections result in rumble which will show up
in your work as an ugly finish. Cone bearings will not do this! As an example,
Derbyshire spec'd their ball bearing lathe at 0.0002" runout. Their cone bearing
lathe is spec'd at 0.0000002" runout!
The principal reason that the WW lathe manufacturers went to ball bearing headstocks
is they will remain very low friction when you load them heavily, such as when you
get the urge to turn a 2 inch steel disk with your lathe... DON'T! If you want to
do big stuff like that, get a "REAL" lathe, not a jeweler's lathe. "REAL" lathes
are cheaper anyway.
Also, job grade ball bearing assemblies, such as you get from Granger are not good
enough for any lathe! This is where the Sherline and Taig run into trouble doing
watch work. They are (or at least were) using job grade ball bearings in their
headstocks. Sometimes you get lucky and get one that is nearly perfect, sometimes
you don't. Both meet the bearing manufacturer's specs.
WW lathes all share a common problem. They weren't made to suffer much abuse in the
bed to headstock bearing surfaces. There are no adjustments to take up any wear.
All modern machinist's lathes have a multitude of "gibs" that are adjustable to remove
these errors. Not WW! So, if you need your headstock to line up with your tailstock,
(drilling comes to mind) it is very important to find a lathe with a nearly perfect bed.
Ok, Collets!
-----------
A standard 8mm WW collet never existed! They are different in a number
of areas that will affect fit and accuracy. Here are a few:
Keyway depth and width (Peerless have the deepest keyways I have seen.)
Body diameter
Body length
Head diameter
(If things were this bad with 5C collets, there would be a revolution!)
If the body diameter of your collet doesn't fit snuggly in the headstock spindle,
the collet will be able to "rotate" to different centerline angles depending on
how much the drawbar wants to pull the threaded end off axis. This will really
screw up your turning! Use the collets made by your lathe manufacturer. Peerless
are quite good in Peerless lathes. They (I am told) really suck in Derbyshire lathes.
A Peerless spindle's index pin is quite capable of pushing a Whitcomb collet off center,
as the Whitcomb collet's have shallow keyways, and Peerless lathe's have deep index
pins. Use the collets made by your lathe manufacturer, or plan on modifying them...
or living with the errors.
Collet use:
----------
Collets will only turn true if they are used on smooth cylindrical rods
that are within a few hundredth's of a mm of the collet's marked size. They will turn
true when chucked on a balance staff's hub, they will NOT turn true if chucked on a
balance staff's hairspring collet taper! They can be made to turn true if you "adjust"
things a little, but most things can be made true with a little "adjustment" ;-)
Assertions about the need for a truly great lathe to make balance staffs:
------------------------------------------------------------------------
Well, if you believe that you cannot chuck a collet on a hairspring collet taper
and be true, then you should also believe that you cannot "rechuck" a piece in
a collet and have it remain true... because you cannot!
That being the case, the only way to make a staff that is true is to chuck the stock
rod once, and not remove it for the entire operation. If you do this, it doesn't matter
if the lathe is all wonked out, the resulting staff will be perfectly true. Makes it
kind of tough to polish both pivots, though. Probably should be doing that on a jacot
lathe anyway. But I don't have one, so, use a cement brass. AKA a piece of 5mm brass
rod chucked in your 50 chuck and carve a centerpoint in the end, and a little shellac.
Turn a new centerpoint in your cement brass each time you unchuck it.
Well, that's enough for now.... I ought to have everyone all upset, so I'll
quit and watch for a while...
-Chuck
-----
Chuck Harris - WA3UQV
cfha...@erols.com
Chuck Harris
...
> Collet use:
> ----------
>
> Collets will only turn true if they are used on smooth cylindrical rods
> that are within a few hundredth's of a mm of the collet's marked size. They will turn
> true when chucked on a balance staff's hub, they will NOT turn true if chucked on a
> balance staff's hairspring collet taper! They can be made to turn true if you "adjust"
Oops! balance staff's roller taper! I hate it when the fingers try to do the thinking
while I am typing.
> things a little, but most things can be made true with a little "adjustment" ;-)
>
> Assertions about the need for a truly great lathe to make balance staffs:
> ------------------------------------------------------------------------
>
> Well, if you believe that you cannot chuck a collet on a hairspring collet taper
^^^^^^^^^^ ^^^^^^ roller
> and be true, then you should also believe that you cannot "rechuck" a piece in
> a collet and have it remain true... because you cannot!
-Chuck
Scott A. Ekleberry
the whole e-mail for reference just in case. You basically said about
everything my instructor said from AWI, and the other people on here SHOULD
READ what you said.
The reason I don't like peerless lathes is that I have been told by enough
people (at AWI, and in private e-mails), that they aren't that good, same
with their collets (and some of the other cheaper American lathes). I do
drill with my tailstock, so it is probably good that I have the better
lathe. Chuck is right, and I basically said the same thing, MAKE SURE YOUR
PARTS ALL MATCH! Get a GUARANTEE when you buy the lathe so you can return it
if the parts don't match, or the bearings are shot.
--
Scott A. Ekleberry
It's About Time!
A full service watch repair shop!
www.itsabouttimeonline.com
SAE...@WOH.RR.COM
"Chuck Harris" <cfha...@erols.com> wrote in message
news:3C86A823...@erols.com...
Billiam
wrote:
>Pent up lathe stuff that finally came to a head:
>Then you need to know the condition of the spindle bearings, and on the bed
>surface. If you see a lathe being sold with a grinding wheel fixture, you
>should consider passing. The grit gets everywhere, and will very quickly ruin a perfectly
>good lathe. After dry grinding you MUST completely disassemble your cone bearings
>and clean them. (as well as the tailstock and steady rest.) For <insert favorite
>deity here> sake get a grinder! Keep it away from your lathe. They are dirt cheap.
<snip>
>That being the case, the only way to make a staff that is true is to chuck the stock
>rod once, and not remove it for the entire operation. If you do this, it doesn't matter
>if the lathe is all wonked out, the resulting staff will be perfectly true. Makes it
>kind of tough to polish both pivots, though. Probably should be doing that on a jacot
>lathe anyway. But I don't have one, so, use a cement brass. AKA a piece of 5mm brass
>rod chucked in your 50 chuck and carve a centerpoint in the end, and a little shellac.
>Turn a new centerpoint in your cement brass each time you unchuck it.
>
>Well, that's enough for now.... I ought to have everyone all upset, so I'll
>quit and watch for a while...
>
>-Chuck
Wow....thanks, Chuck. I'm not even in the market for a lathe and
I found that very interesting! ;-)
Rob Kramer
[lots of corrections] :)
Fantastic post, I saved it as well and applied your corrections. Actually
sometimes I feel like I'm learning Enlish all over again, all that
metalworking terminology.
This one together with Scott's post should make lathe shopping on eBay a
bit safer I guess. I'm first going to see the watchmaking / lathe turning
videos I ordered though.
Cheers,
Rob