On Jul 5, 10:40 pm, "DoN. Nichols" wrote:
On 2010-07-05, Searcher7 wrote:

On Jun 28, 7:59 pm, "DoN. Nichols" wrote:
On 2010-06-28, Searcher7 wrote:

[ ... ]

Or perhaps a collar with a circular wedge that would be put on the
collet chuck body before inserting the body into a solid sleeve that
is bolted to the spindle. This way the collet chuck would seat first
and then the collar would be screwed back resulting in the circular
wedge sliding between the collet chuck body and the solid sleeve.

I still don't really understand what you are suggesting.

Ok. I have to learn a graphics app to make explanations easier.

Yes -- but make sure to get one which produces (or can produce)
an open format image, not something which is Windows specific, because I
won't be able to view it. :-)

PDF is quite easy to view on any system.

Ideally a vector program and a way to convert to PDF.

Line drawings are better done in two-color GIF format (best
compression, and no loss of detail to the compression, which is a major
failing of JPEG format.

[ ... ]

Is your lathe the green one, or the blue one?

Hmm ... I see missing things so I must have lost the previous
article when the newsreader locked up.

Lots of typing lost.

That is why I always type in a test document(Notepad), with frequent
saves when I am typing something long.(But I don't have to worry about
"Google Groups" crashing).

Normally, my saves are automatic. My newsreader invokes the
editor of my choice (jove, FWIW) for composing articles, and if the
system crashes (most often from power failure -- the OS is rock stable),
it saves the data to recover.

I don't have power failures.(Which is amazing, considering the old
wiring in this complex). It's usually software that screws me up.

What happened, instead, was that the newsreader itself hung up,
and forgot about the article which I had been replying to.

I just checked, and found the article's editor file was still
there, so I'll append it to the end of this one.

Oh yes -- one thing was about Lyndex collets. I had to order a
new one (5/8" hex) from MSC. The box is the same as your set, so that
must be the newer box. Anyway -- the collet has no markings on it to
say it is Lyndex, so don't worry.

OK, but I put those back up on eBay, because I won a set of 5C Royals
from 1/16" to 1-1/16" at every 1/16th.

O.K. Royals are one of the two which I have in my collection
which are actually marked as to maker. The other is Hardinge.

Anyway -- I was looking up ER collets to try to find a best
choice for you -- The ER series holder would be shorter than any 5C one,
so a better choice for you. ER-32 will handle up to your full spindle
bore and it does not need a drawbar if you make a nose adaptor for your
lathe's spindle.

Yes. A realistic comparison for my lathe would be between ER32 and 3C

http://littlemachineshop.com/product...ProductID=2228
http://littlemachineshop.com/product...ProductID=1991

Note that the ER set would cover *all* sizes between the 1/8"
and the 3/4", while 3C (or 5C) collets only work close to their nominal
size.

Ok. Just to get this straight. Even with every 1/64th I'd could still
have work holding issues with the 5C/3C collets, correct?

(I know the clamping range of an ER40 collet is .040").

(The 3C would need the collet closer).

For feed-through the spindle, you would have to make your own
nose flange mount body using the other (MT-3) one as a pattern to be
able to feed through the spindle. For short things, however, you could
hold them with the MT-3 shanked adaptor and a solid drawbar.

But the real question is whether you can cut a Morse thread with
a 1.5 mm pitch. Without that, you could make everything else right, but
not be able to make something which would accept the nosepiece. The
precise thread in inch units would be 16.9333 TPI. 17 TPI would be
close but not close enough 0.0667" error in a 1" thread with 0.058" per
thread, so it would be over a full thread in error.

And 17 TPI is not likely to be found on any lathe gearbox
anyway. 16 TPI is common, 18 TPI fairly common, but 17 you would have
to find gears for -- or better metric conversions gears for the lathe.
And since it has an inch leadscrew pitch, you could not use the
threading gauge -- you would have to keep the half-nuts engaged and hand
crank the spindle backwards to the start of each threading pass.

It's a good thing I got that rotary table and making gears is at the
top of my list. :-)

BTW The drawbar for the Morse taper shank ER-32 adaptor is cheap
enough (LMT # 2224) at $4.29 so why take the time to make one?

I wouldn't. :-)

And would ER40 instead be a problem? The sizes it covers would be
close to what my 5C set covers, so if I had to transfer work between
these collets, ER40 would seem to be the best bet.

Since I now have 5C and R8 covered for milling purposes and the
discussion has moved toward ER collets, and I correct in assuming that
you think I should put the priority on getting ER instead of 3C, which
was a bigger priority than MT3?

So -- start with a MT-3 ER-32 collet adaptor and collets. This
will get you something which you can use with a drawbar at first, and a
pattern for the needed dimensions. Then you make a piece of steel which
mounts on your lathe spindle, bore through it and at the proper angle
for the back of the ER-32 collets, and then turn down the OD and thread
for a M40-1.5 thread. (This means that *before* you commit to this,
you need to make sure that you can *cut* a Metric thread of 1.5 mm
pitch. If you can't find the gearing to do it -- don't get started.
You have to plan ahead to figure out what *can* be done before you start
buying parts which may or may not work. It appears that 5C collets are
just too large for your lathe.

BTW. I'm now also receiving a new set of R8 collets for my mill/drill:
120590702108

O.K.

Three still in wrappers.

(Yes, I know they are Lyndex. But I may need to center cut something
accurately). :-)

O.K. Lyndex, Royal, Hardinge are all good choices -- and all
expensive.

Now -- the question is whether the end mill happens to be
sharpened properly on center. Well -- you won't be able to blame the
collets, anyway. :-)

I found myself getting heavily the whole tool-making/grinding/
sharpening area. And I'm keeping my eyes open for a tool cutter/
grinder.(Surface grinders are out, because I don't think they make
them small enough). :-)

Newsgroups: rec.crafts.metalworking
From: "DoN. Nichols"
Subject: Precision vs. "Regular" collets
References:
Organization: D and D Data
Followup-To:

On 2010-06-28, Searcher7 wrote:

On Jun 27, 11:47 pm, "DoN. Nichols" wrote:

[ ... ]

Damage the knurls? I was assuming a slip fit of the pin in
beside the ring and with light pressure being used to spin the ring on
to a reasonable position.

Since it was packaged with the collet holder, I keep trying to
find a reasonable use for it. Perhaps some previous owner had bigger
fingers and needed that to reach down into the area.

No ones fingers are small enough to reach down in between the wall and
ring. You have to push-turn to screw it on or off. You can stick the
small rod in between the ring and the inside wall, but you have to
tilt when you bring it around so it will dig in and not *slide* around
the ring.

O.K.

Sure -- you could probably thread it on a little more if you
were pressing in the collet nose while installing the ring, but that
would limit the size range of the collet.

Well, if I pressed hard enough to hurt my fingers it would turn
perhaps 1/16" more.

No point to doing that anyway -- you've got plenty of travel
when closing the collet by the front ring.

Yup. Enough to clamp a rod in the collet.

That is what matters.

BTW Relative to an earlier part of this thread -- the Lyndex
collets. I needed a 5/8" hex collet (I had most other
hex sizes, but not the one I needed) so I ordered one from MSC
(new of course). Well ... it arrived today. The box looks the
same pattern as yours, so they must be newer than what I
originally had. Anyway -- there is no marking of Lyndex on the
collet anywhere, and from MSC, I would not expect a
substitution, especially in the same packaging. So you can feel
comfortable with the set you got.


BTW. Here are those 5C Royals I'm getting: 120585499838

But it will need a tricky bit of work to cut the slit along one
size to allow the screw to clamp it onto the body. You'll need the mill
and some way to mount the rather large piece of metal to do that.

How about three slits in a tapered sleeve that is bolted to the
spindle. The sleeve would be slightly thicker at the front end, and at
the base there would be a tightening collar that is I.D. threaded at
the rear and rounded at the front end? Screwing it forward would
tighten the sleeve around the collet chuck.

Make that a ring -- perhaps 1-1/2" thick, with a set of radial holes
drilled the same size as those in the bit black ring so the same tool
would work for either. Make 3/4" threaded, and then taper the other
3/4" a tapered surface to match the top portion of the holder. You
don't want the collar to have to thread all the way up from the bottom,
put the threads only on the last inch or so before the matching taper.
Probably make the tapers pretty close to the taper on the nose end of
the collets as a good start.

And you want the holding grip at the free end, not where the
holder mounts to the chuck.

Anyway, I have plenty of time to worry about this. But take a look at
the 5C collet chuck he http://www.cdcotools.com/

That is so tempting, because I have never seen it so cheap. But since
the MLA-21 is a better option I guess I should stick with that idea,
unless I definitely find out this would be too large for my lathe. If
so, then perhaps all these 5C options we're discussing are to large.

That's the MLA-21. The conventional 5C collet chuck. And the 5C collet
chuck that is usually held in chuck jaws.(Then there is that direct
"into the spindle" idea).

(Like I mentioned, the ability to flip the work around, center, and
machine it seamlessly to match the opposite half is what I'm after).

Cut the threads and the taper before you slit it. To slit it,
you would need the rotary table with some means of mounting the cylinder
to it. You *could* drill through the base for Allen head cap screws to
reach through the spindle flange to accept nuts. You could probably
tighten the screws with a long Allen key through the cylinder before
sliding in the collet adaptor. That would be more convenient I think.

I think I understand, but I'll have to read this a few more times. I'm
assuming you don't think a tightening ring/collar can be tighten the
grip on the chuck body effectively *without* a tool, correct? (I'm
thinking about the drawbacks of a thicker, heavier ring).

Well ... it could have a built-in tool of sorts. The ring could
be split with a pin coupling the two ends with a lever operating a cam
to clamp it. But this would mean something which is not perfectly
balanced, so it would make the lathe dance at higher spindle speeds.

And the ring I described could be loosened and tightened with
the same tool that the collet closer part is -- so one fewer thing to
deal with. Just slide in the pin, twist, and done.

The great thing is that I wouldn't need to thread the bar. The turned
down end fits in the un-threaded holes.

Or perhaps a collar with a circular wedge that would be put on the
collet chuck body before inserting the body into a solid sleeve that
is bolted to the spindle. This way the collet chuck would seat first
and then the collar would be screwed back resulting in the circular
wedge sliding between the collet chuck body and the solid sleeve.

That sounds a bit more difficult to make to me -- but I may be
mis-interpreting what you are suggesting.

Think of a collar with three slits in the rear half of it. That half
tapers to form three circular "wedges". When the collar is turned, it
will thread/wedge itself between the sleeve that is bolted to the
spindle and the collet chuck body.

I don't like the slits in the rear half. That makes it less
rigid. Make the back half as close a sliding fit as possible, and slit
the open end so the ring can clamp at that end -- closer to the place
where the cutting forces are applied.

The body is 2.750" long and the idea was to use the forward .750".

The rear 2" would seat. And a .500" collar on the front would screw
rearward only .250" max., wedging itself between the 5C chuck and
front part of hold it is seated in.(But again, I'll get back to all of
this).

I agree that the MLA-21 would be the better choice. What
remains to be seen is how difficult the machining is to make it from the
castings.

[ ... ]

I'm starting to think that this should be my first project.

I think perhaps the first *serious* project -- after you have
turned a lot of metal into chips playing with the lathe to learn it
first. Remember -- proper project castings cost more than cheap metal
to play with.

Ok. BTW. I received a reply back from Andrew concerning the MLA-21. He
said that my lathe does strike him as being a bit small for the collet
chuck, both for mounting it and making it.

I agree. You really need a larger lathe for a lot of what you
want to do.

If you had a friend in the area who had a larger lathe, he could
help you to build the MLA-21, leaving only the problems of actually
using it.

Well, you mentioned that it should be made on my lathe. correct?

And he mentioned the
drawing and instruction set which I'll order.(But I'll have to wait,
since I don't have credit cards, and I will have to go to the bank to
get a check book).

O.K. I've never seen a back account without a checkbook before. :-)

A savings account. I did get a checkbook some years ago when I opened
a checking account so I could use a Debit card. But the checkbook got
wet and since I never needed to use it anyway...

I attempted to take the lathe out of it's box today. Unfortunately it
looks as though I'll have to tear the box off around it.

I was (and so were you) pointed to a set of pages which included
the information that the lathe base is secured to the bottom of the box
with a set of bolts -- ones which were probably bent in shipping. You
have to remove those before you can take the base out of the box.

Yes. I have most of those pages already bookmarked. I'm going to be
doing a lot of measuring of the headstock components anyway, to have
everything documented.(I want to keep the lathe bolted to the wood
"pallet" until I get it where it needs to be).

Why? It will be a bit easier to move around and examine without
the pallet. This is a lathe small enough so you should be able to lift
it by yourself, after all. The pallet was to keep the lathe from
shifting around in the box and damaging parts packed around it.

Right now it is next to my mill/drill in the kitchen on this big
butcher block table I won off eBay for $60. :-)

Is your lathe the green one, or the blue one?

It's the red one. I think the new ones now are grey.

Oh -- collect a whole rainbow. :-)

I guess it's a marketing thing. But they do now have a 7" x 16". The
biggest difference being the 500 watt (0.67hp) adjustable-speed
brushless DC motor. As opposed to my 350 watt (0.47 hp) adjustable-
speed commutator-equipped DC motor with digital readout. (My machine
is still a little heavier).

Really -- changing out the spindle for one which will accept 5C
collets directly is something *well* beyond your reach where you are
living.

Ok. Let me throw out one more idea. What would be the plausibility of
a new spindle design with enough mass at the front to allow a threaded
bore that accept a 5C collet directly, eliminating the need for a
collet chuck, and still allowing pass-through of .75" and under?

How big is the diameter of the register in front of the
chuck-mount flange? Compare that to the diameter of the front of the
collet -- and add the thickness of enough steel to make it strong. If
you make such a change, you will probably have to make an entire new set
of back plates for chuck mounting.

If this is possible, a back plate or two would be the least of my
worries. :-)

(BTW. I also wouldn't be able to use reverse with the collets in such
a set up).

I have now seen the photos -- and this tells me this is *not* a
reasonable project.

Use your lathe. Find out what it is capable of doing and what
it is not. Then will be the time to think of making or buying larger
machines.

No problem. This is really about what is possible with this lathe. I
just want to go in knowing what all operating parameters are. (Actual
and plausible via modifications).

Remember -- your chucks can hold things very nicely. If you
want to avoid marring from the grip of the jaws -- perhaps you should
think of building a collet nosepiece for some ER style collets.
Generally, the nose cap is the hardest thing to make -- so get just the
nose cap, or the nose cap and a MT-3 shank body, and use the MT-3 shank
one as a pattern when making a body to fit your spindle nose. You have
the options of an ER series just big enough to pas the 3/4" workpieces
through the spindle, or a larger one which could be used for gripping
short workpieces.

O.K. ER-25 goes up to 5/8" from a start of 1/16". A little
small for your 3/4" through passage.

ER-32 goes up to 3/4"

This eBay auction (and lots of others) is a ER-32 collet chuck
with a MT-3 shank:

390084614108

And some ER40 options:
330372938101
390216414569
140424332828

Thanks.

Darren Harris
Staten Island, New York.