On Jun 10, 1:26*am, "DoN. Nichols" wrote:
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. :-)
That's the reason I got the imported collets to begin with. :-)
* * * * And R8 is not a work-holding collet -- it is a *tool-holding*
collet -- specifically end-mills.
Yes. I had decided to not get the R8 end mill holders and get the R8
collets instead.
* * * * 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.
My mini lathe has a .787 spindle bore, so I figured I would get an
MT-3(3MT) set so I wouldn't need a collet chuck for that range up to
3/4".:
http://littlemachineshop.com/product...ProductID=1948
And a set of R8 collets to cover the endmills for my mill/drill.:
http://littlemachineshop.com/product...ProductID=2872
I just have to determine what sizes are best to get that give me a
good range of options for end mills.
(But not necessarily the collets in these links, since they are also
imports).
I would have considered these if I had gotten that Vertex dividing
head:
http://littlemachineshop.com/product...ProductID=2999
But that particular set only goes up to 1/2" anyway.
I'm not sure of what, if any MT2 collets I should get. (My lathe
tailstock and rotary table center bore are MT2).
http://littlemachineshop.com/product...ProductID=1752
As for 5C. I still have that "poor man's" 5C collet chuck, spin
indexer, hor/vert. collet fixture, and collet blocks.
http://littlemachineshop.com/product...ProductID=3842
I'm thinking 1/8", 1/4", 3/8", 1/2", 5/8", 3/4", 7/8", 1" "precision"
collets.(In round, square and hex).
Getting all these collets from a quality manufacturer will be tough.
(The various spindle and bore standards are killing me).
* * * * 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.
Randy said that the problem he's found with the cheap collets is that
they are all undersized. If this is generally true I wonder if it
would be a plausible project correct the inaccuracies of at least some
of the imports. Of course, there will be concentricity as well as bore
size issues. (Which reminds me, I have to get a taper attachment).
Another issue is that my set of 5C collets were packed in four
different kinds of packages, which would probably mean they are even
more inconsistent.
http://s290.photobucket.com/albums/l...t=IMG_0165.jpg
Thanks.
Darren Harris
Staten Island, New York.