On Jun 14, 10:57*pm, "DoN. Nichols" wrote:
On 2010-06-14, Searcher7 wrote:

On Jun 12, 8:52 pm, "DoN. Nichols" wrote:
On 2010-06-11, Searcher7 wrote:

On Jun 10, 1:26 am, "DoN. Nichols" wrote:

* * * * [ ... ]

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.

The end mill holders are better. R8 collets holding end mills
tend to slip with heavy cuts, causing the end mill to walk deeper and
deeper into the workpiece -- or even *through* it and into the mill table
or the vise.

It appears that you are conveying that the spline on an R8 end mill
holder

* * * * What spline?

* * * *more than makes up for the larger surface area contact of an R8
collet.(Or am I missing something?).

* * * * Quite a bit, if you are expecting a spline somewhere in the R8
end mill holder. *And actually, there is a greater surface contact area
on the end mill holder than on the R8 collet.

* * * * Let's describe the end mill holder to perhaps make it clear.

* * * * Start with a shank which has the exterior dimensions of the R8
collet (or whatever holder is needed if not an R8 spindle).

* * * * Then bore and ream to size the precise diameter of the end mill
shank so it just barely slips into it.

* * * * Then there is a special setscrew with a flat point and a
45-degree bevel which precisely matches the "Weldon flat" (also with the
45-degree bevel) in the side of the end mill's shank.

* * * * The 45-degree bevel plus the flat prevent the end mill from
being pulled down out of the end mill holder.

I erred in using the word spline. I meant slot. There is a groove I've
seen along the length of an R8 shank.

* * * * There is another style -- common in the UK and almost unknown
here -- called the Clarkson collet. *It includes a threaded part which
grips a threaded end on the end mill shank (as hard to find here as the
Clarkson holders) and a hardened center in the holder presses on the
machined center in the end mill. *These *do* have a collet to hold the
end mill where it exits the holder, but are proof against the end mills
pulling out -- as long as you can find those end mills. :-)

I don't have an R8 spindle machine, but for end mills I prefer
end mill holders for the NTMB-30 and NTMB-40 tapers for my two machines
(with an adaptor allowing me to use the 30 taper holders in the larger
machine as well.)

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

With the disadvantage that you can't pass long workpieces
through the spindle as you can with 5C (or even 3C) collets.

It would of course have to be 3C for my lathe. since I see no
advantage to getting 5C for the spindle.

* * * * Certainly.

http://littlemachineshop.com/product...ProductID=1991
http://littlemachineshop.com/product...ProductID=2240

* * * * O.K. *The first is the collets -- the second is the adaptor to
allow you to use the 3C collets in your Morse taper 3 spindle -- but
without the drawtube assembly, which is covered by your following two
links.

What about using split bushing so as not to marr the work when being
held in the chuck from through the spindle? Wouldn't something like
this make a collet unneeded?

The drawbar for those is hollow, while the drawbar for what you got is solid
(it uses internal threads in the collet back, while the 3C and 5C use
external threads instead.

http://littlemachineshop.com/product...ProductID=2374....
http://littlemachineshop.com/product...ProductID=2728....

* * * * Why post both? *One is pre-cut to fit a specific machine
(yours?), while the other is the same thing with a longer drawtube which
can be cut to fit whatever machine you have.

Yes the 7" x 14" is mine.

* * * * The uncut one could probably be easily adapted to my old
Atlas/Craftsman 6x18" lathe -- but I don't use it any more, so there is
little point in doing that. :-)

* * * * Note that these are all handwheel type. *What I am using is a
lever locking style -- you adjust and lock a setting once for a collet
after installing it, and you can release and lock the collet with a
lever at the other end of the headstock -- even while the spindle is
still turning. *This is used with a turret in the lathe, and often with
a pneumatic pusher to feed stock to a stop on the turret without
stopping the spindle to move to the next part.

If you were in my position, , with a mini lathe, would you go with the
handwheel type that you can purchase or still make one of the "lever
locking style" type?

BTW. I notice that some 5C collets have either or inside/outside
threads. Would it be more desirable to concentrate on getting just
those that have both?

* * * * The outside threads are all that is used by the drawtube. *The
inside threads are for a work stop. *It screws into the internal threads
on the collet, and has a threaded rod which can be adjusted to control
the depth a workpiece can be pushed into the collet, and a nut to lock
the threaded rod so you can change many parts through the setup while
the depth stop remains properly adjusted.

* * * * This can be used in a lathe spindle, or in the collet spin
holder, but would probably be quite awkward with the square or hex
collet blocks.

Yes, I know the purpose of the inside vs. outside threads, but what
gets my attention is what you said about using a collet stop in a
square or hex collet block. This actually has not even crossed my
mind.

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).

The only disadvantage of the end mill holders is the extra
length. But remember my warning about the R8 collets slipping with
heavy cuts.

But since this is a mini-dill/drill would I even have the power to
have work holding be an issue with the R8 collets

* * * * The R8 collets are *not* work holding collets. *They are tool
holding collets -- typically end mills. *This is why they have internal
threads for a drawbar, not external threads for a drawtube. *You don't
have shanks long enough on the end mills to need to pass them through
the spindle. :-)

I shouldn't type when I'm tired. :-) We were discussing tool holding
and I substituted the word "work" for "tool".

* * * * And you might indeed have problems -- depending on the size of
collet which you are using and how aggressively you are feeding the
workpiece into the end mill.

I thought I saw R8 end mills in my collection. Nevertheless, perhaps
it is best to have both end mill and collet options.

*** I just have to determine the popular end mill sizes so I'll have
the collets ready.

(Most of my work will be in Aluminum, Brass and Delrin, with some mild
steel thrown in).

* * * * * * * * * * * * * * * * * * * * * * * * * as opposed to the
end mill holders? (And there is the limited travel distance that is at
a premium on one of these machines).

* * * * *That* could be the major reason for using collets instead of
end mill holders -- especially in the larger sizes. *The end mill
holder has to project at least far enough to bring the setscrew out of
the spindle where you can tighten it -- and the larger the end mill, the
more likely that you won't have *any* room for the end mill shank to
project into the spindle -- which means that you could not hold (for
example) a 1" shank end mill in your R8 collets -- but you *could* hold
one in an end mill holder -- if you have enough room between the table
and the spindle. *The larger the vise, and the larger the end mill
holder, the less space for the workpiece itself. :-)

Yes. One reason I'm looking into more innovative work holding options.

http://www.actmachines.com/cart/products.php?id=87

(So I can get around using a vise most of the time).

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.

Look for a good 3-jaw chuck to fit it instead.

Deciding on a chuck has been my biggest problem. I guess a 6" chuck
would be possible witht he 6" rotary table I have, but a 4" would have
a lower profile. (And I can probably still get one of those used 4"
Buck Adjust-Tru 3-jaw lathe chucks with the removable # 10 Brown &
Sharpe taper back plate).

* * * * On your rotary table, you either need some extra diameter for
clamping the backplate to the table, or you need to know where you can
drill holes *through* the chuck for bolts to engage T-nuts. *My
preference is the smaller chuck with a backplate made for it which is
as large as the table, so the hold-down bolts can go outside the
diameter of the chuck and you won't need to drill through the body of
the chuck.

I assume a 4" chuck might be the best option.(Perhaps 5"?).

(The seller was selling one of those 4" adjust-Tru chucks for $159).

* * * * The backplate needs a spigot to engage the center hole (Morse
taper in your case) to center the chuck before you tighten the clamp
bolts.

Yes. I wonder if a one piece backplate with MT2 taper spigot can be
made. And if it would theoretically be the best option.

* * * * If you are going to drill through the body of the chuck, you
need to know *where*, and you either need a 3-jaw chuck on a 3-slot or
6-slot table, or a 4-jaw chuck on a 4-slot table.

I have a 4 slot table, and don't intend to have to drill through the
back of the chuck.

* * * * *But* -- what I was talking about above was for a dividing head,
not your rotary table. *The dividing head normally has a threaded nose
onto which the 3-jaw chuck threads.

Yes, but the chucks I've seen tend to be small.

Since the dividing heads are too large I won't be getting this:
http://www.shars.com/products/view/9...amp_5C_Adaptor

This would be for a rotary table:
http://www.shars.com/products/view/8...ith_MT_2_Arbor

But 4" or 5" would I guess be desirable.

The ideal situation would be to have the option of transferring a
single chuck between the rotary table and the mini lathe. (But the
chuck I get for the lathe should be a 4-jaw).

* * * * No -- the chuck you should get for the lathe should be *both*.
The 3-jaw is more convenient and quicker -- and very good for hex
workpieces as well. *The 4-jaw independent is better for precise
centering (slower though), and far easier to use with square workpieces
or strange shapes like castings for a part.

Yes, I know. I already have the 3" 3 jaw chuck that came with the
lathe.

So now I need a 4 jaw. One that I can transfer to my rotary table.

Hmmm. Perhaps I can just make an adapter plate for the 3" 3 jaw and
use that on the rotary table instead. (I can't think of why I'd need a
larger chuck for that purpose at the moment).

Just because something *has* a Morse (or other) taper does not
mean that it is worth while getting collets to fit it. The tailstock
taper for a lathe is for centers -- or for drill chucks on an arbor, or
drill bits fitted with a Morse Taper shank.

Thanks. Having no use for MT2 collets makes my shopping list smaller.

(I have an MT2 live center for the lathe tailstock and just need an
MT2 dead center for the rotary table). :-)

* * * * O.K. *You also need a MT-3 dead (solid) center for the
headstock, and a dog driver plate to allow turning between centers.

Yes. It's the face plate I'm debating on whether I should make or buy.

Getting all these collets from a quality manufacturer will be tough.

It will also be *expensive* -- especially from Hardinge. :-)

(The various spindle and bore standards are killing me).

One reason to avoid getting collets for things which don't need
them.

Yes. I see why there are so many of these available on eBay that are
not the *standard* sizes.

* * * * They are *somebody's* standard size, and eBay is a way to reach
those somebodys if they don't know how to find the real vendors.

Agreed. But I think a lot of guys may just be getting rid of the
collets that they don't normally use.

Funny. I just got a message back from an eBay seller who has one
Hardinge collet in a lot of 26,but has the Hardinge name in his title.
150449751040 (The other 25 are unmarked, so obviously they are
imports).

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.

And someone else (quoted above) said that in *his* experience,
some are undersized and others oversized.

Yes. I was just hoping my lot was undersized. :-)

* * * * As long as you are hoping -- hope that they are right on. :-)

Good point. :-)

* * * * * * * * * * * * * * * * * * * * * * * * * *Assuming I decided
to get the equipment necessary to correct the problem. (But this
doesn't seem like a newbie project).

* * * * No -- but it could be a learning project -- perhaps lose one or
two of the collets as you learn -- then buy replacements. :-)

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.

I put the batch on eBay to see what happens. 140417041012

(Other sellers can learn from me when it comes to including *all* of
the pertinent details in their auction ads).

And if they are *sufficiently* undersized, you can fix both the
size and concentricity problems in one operation. Note that the collets
are hardened, so don't expect to turn them right -- you will have to
grind them to the right size, using a toolpost grinder on the lathe.

That is a piece of equipment I don't have and don't think is available
for my lathe, so it would probably have to be made.

* * * * Or adapted. *Makers like DuMore make toolpost grinders for a
wide range of machine sizes.

I missed one a few months back that was right here on Staten Island.
DuMores go for a premium.

* * * * Or take a block of aluminum, mill dovetails to fit your
quick-change toolpost, bore it to fit a air driven die grinder (some
have cylindrical handles, which are easier to use for this), slit one
side and add clamp bolts to tighten it onto the die grinder, and you
have a quick and dirty toolpost grinder. *(And *dirty* applies to *all*
toolpost grinders. :-)

Yeah, but can I get TIRs within .0001. :-)

You will have to spend quite a bit of time protecting the bed
and other precision surfaces from the abrasives from the grinding
operations.

And every time you change out one collet for another, you will
need to clean the taper and bore of the collet adaptor or some grit will
hold the next collet off-center so it will wind up no better, and
perhaps worse than before.

Yes. you mentioned this to me in the past, which is why I didn't get a
tool post grinder.

* * * * Better to avoid using one as long as you can. *I have a couple
of them -- one the right size for my lathe for OD grinding and one
smaller one better for ID grinding -- and I have yet to use them. *They
are there for when I discover that I really do need them, but in the
meanwhile they are not making me have to clean the lathe more than
normal. :-)

Perhaps your 6 X 18 could be your specialty lathe for this purpose if
it comes to that. (If they are the correct size).

I would suggest that you not worry about the accuracy of the
collets until you *need* it. Normally, even the inexpensive collets are
significantly better that a 3-jaw chuck.

(Which reminds me, I have to get a taper attachment).

For what projects? And is one available for your lathe? You
may have to make one from scratch.

Yup. This is something I'd have to make also. The projects would
involve making morse tapers when I get more into the tool making
aspects of the hobby.

* * * * You can buy blank Morse tapers. *I've bought several with a MT-2
shank and a rough 1" diameter and 1" length external section which I
have machined two of to make shanks for a couple of TapMatic tapping
heads (two different sizes), and at least one spare for some future
project.

I'd only want to work with tools that are hardened. So tool grinding
is next on my list.

* * * * For many things, you can buy Morse taper arbors with the other
end to fit other things -- like Jacobs taper for various drill chucks
and such, threaded or whatever.

* * * * As for making female Morse tapers -- you can drill small full
depth, and then drill larger at shallower depths to approximate it, and
then use a Morse Taper reamer to produce the female. *You can get both
roughing and finishing reamers.

* * * * If you are working on hardened metal, you will need the taper
attachment -- and the toolpost grinder to make the precise surface you
need. *And -- it is really tricky setting up a taper attachment to
precisely match a Morse taper. *You will also want a set of Morse taper
gauges to check the results if you are forming the taper with a taper
attachment.

If I remember correctly Morse Tapers' deviate .06 inches over 1 foot.

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.../Tools/?action....

Or perhaps they were selected as the best (or the worst) of what
came in. If the different packaging means different makers, it may
still not make much difference -- they may still all be pretty good.

Going with the odds, that probably wouldn't be the case. But I
seriously doubt the company would bother checking the TIR of all their
collets anyway. :-)

* * * * As do I. *So it is more likely that they bought as good as they
could afford given the price they planned to sell for, and would
hopefully be good enough for most purposes.

Thanks a lot.

Darren Harris
Staten Island, New York.
* * * * * *--- Black Holes are where God is dividing by zero ---