On 2010-06-10, Searcher7 wrote:
On Jun 9, 4:24*am, Gunner Asch wrote:
On Tue, 8 Jun 2010 18:13:30 -0700 (PDT), Searcher7
wrote:
I entertained the idea of filling out the rest of my set of 5C collets
several years ago. Now I'm thinking about it again, but there is a
possible issue which I didn't really consider originally.
For those who have experience with the import(regular) collets can you
give me an idea of the kind of problems you've run into, if any, due
to collet inaccuracy? (Before I get the other 32 to complete my round
set).
And am I correct in assuming that even import(regular) collets
wouldn't be anywhere near 1/64th of an inch off of perfect?
Can I also assume that as long as the correct collet is used there
really shouldn't be any real wear?
[ ... ]
Unfortunately...far far too many importe (Asian) collets are under or
over sized. A 5C collet has at most..a .015 grip range..and most of them
are .006. *Ive seen far too many of them that were in that 15 thou
range..but a .500 collet may open to .485, and close to .497....which
really doesnt help much when your stock is .502 +/- .004
Hardinge, Lyndex, Royal, etc etc and several other german or polish made
brands are Good stuff.
[ ... ]
Ok. So I should concentrate on getting common sizes from Hardinge,
Lyndex, and Royal. Do these manufacturers make collets for MT2, MT3,
and R8?
R8 -- yes. MT2 and MT3 are less common these days. Hardinge
*might* still make them, but probably not the others. And be sitting
down before you ask for the price of *any* Hardinge collet. :-)
And R8 is not a work-holding collet -- it is a *tool-holding*
collet -- specifically end-mills.
As for the MT-2 and MT-3 -- the most likely place to find them
is from the same people who sell the import machine tools which
currently use them.
The discussion was about 5C collets, which are the ones which
come from many makers in many degrees of quality.
Also, I'm thinking that I probably should get new collect blocks also,
since the ones I have were picked up from the same seller I got the
import collets from.
Don't worry about it. The typical use of a collet block is not
going to require the accuracy that you want from a lathe spindle. The
most common use of the hex collet blocks is milling a hex head on a bolt
which you have made in an uncommon size. The same thing with a square
collet block -- making the screw heads found on older lathes for common
locking screws. The precision is not really that important. The block
and the collet is simply a convenient way of holding the workpiece,
especially if you don't have a dividing head with a 3-jaw chuck on it.
BTW. How accurate can one expect to make collet blocks for other sizes
where they are not available?
You can *expect* any degree of accuracy you can imagine.
Whether you will *get* it depends on your skill and the accuracy of the
machines you are using to make them.
Enjoy,
DoN.
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