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.
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.
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.
(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.
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?
* * * * 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. :-)
Good Luck,
DoN.
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.
[ ... ]
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.
* * * * 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.
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.
[ ... ]
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.
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. :-)
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.
* * * * 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. :-)
[ ... ]
* * * * 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.
[ ... ]
* * * * 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
[ ... here is where I was when the newsreader locked up ... ]
Without actually going down and measuring, I think that the OD of the
bearings on my Clausing 12x24" with a 1-3/8" spindle bore is on the
order of 5" -- which I think is larger than the dimensions of your
headstock in the area where the bearings live.
I'm sure *everything* is bigger on your Clausing than on my mini-
lathe. :-) (Including the bearings).
That is why it can accept 5C collets in a spindle adaptor -- it
is big enough. Yours is *not* If you want to handle 5C collets, plan on
at least a 10" lathe -- which you will probably have to strip down to
components and carry them up one at a time.
I believe that even the South Bend "Heavy 10" will not handle
the 5C collets in the spindle -- just the 12" swing or larger.
* * * * I was wrong about this, at least.
* * * * [ ... ]
And the wedges are more replaceable than the toolpost body. :-)
They would cost less -- if you could find a place to buy them
separate from the toolpost.
Making new ones would probably be easier. (After all, I have the
templates). :-)
If you are up to cutting a three-start internal thread on an interrupted
cut.
Well, I'm not thinking of making the internal cylinder. I won't worry
about that and concentrate on sliming down the existing wedges.
* * * * But if you have to make the wedges, you need some way to hold
them (fixture them) while you turn the partial threads on the internal
surface to engage those on the OD of the cylinder.
That is why I'd do the threads first. And then cut/mill away the body
which initially would be large enough not to worry about workholding
issues.
And look at the complexity of the other parts of the wedge. You
have to make some of those to use for fixturing while you cut the
threads.
I'm not sure what that means. But outside of measuring everything
accurately, determining the correct cutters would seem to be the
biggest issue. I can visually see inconsistency from one thread to the
next.(The depth shape and the width). So the margin for error is
relatively high.
* * * * Maybe -- maybe not. *But the question is how are you expecting
to hold a partial shape so you can machine another surface. *You have to
plan the sequence carefully -- and make things that will hold those
intermediate shapes.
Without taking it apart again the wedges are about .75" max in width,
so that will be the thickness of the stock I start with. After the
threads are done I can cut of the work piece and go to work on the
angles.
Nevertheless, that's a bridge I'm don't intend to cross. All I need to
do is work on the existing wedges.
* * * * Good!
But I think that they would be easier to file or sand down in the
critical area.
How about emery paper on the edge of a glass plate? (Or perhaps I can
use this item I won on eBay: 330442158063)
Hmm ... depends on the quality of the surface plate. He says
that he checked it flat with a square. :-) To *really* check it, you
need a setup with a micro-inch reading sensor traveling on arms
supported above the surface. The lowest grade should be flat within
0.000050" (50 micro-inches), and as the grade goes up, the number of
allowed micro-inches of deviation go down. There is no way you are
going to check that with a square. :-)
Yes, I know. :-) BTW. This surface plate is on my next Enco purchase
list:http://www.use-enco.com/CGI/INSRIT?P...=949402&PMAKA=...
(When it is no longer back ordered). :-(
* * * * O.K. *That one is class-B (20 micro-inches), and dirt cheap for
the duration of the sale. *It is not a 2-ledge one, which is a bit more
convenient for holding certain types of measuring tools onto it.
* * * * But once you have it -- you can use it for a check on how good
your metal one is. *Smear the surface of the granite one with thinned
spotting blue (expect your hands, and everything else around to turn
blue too :-), then slide the metal upside down on the granite and look
at the pattern of transfer of the dye. *Large areas with no die pickup
indicate problems -- perhaps something has hit the surface of the metal
plate and forced bulges around a dent. *(That is one benefit of the
granite -- it just makes a tiny hole, with no bulges.)
Near where I used to work was a place that had regular "parties" in
show rooms they created for kitchen cabinets, countertops, etc. At the
end they would throw out the granite countertops and smash them. (I
never could catch this happening at the right time).
* * * * Be sure to clean both surfaces properly when you are done, and
rub the metal one down with an oil to prevent rusting.
Thanks. BTW. I missed out on some lapping blocks with miscellaneous
stuff because I didn't bid high enough.(I couldn't find the value
while searching the internet). 250650212085
But if it is not sufficiently accurate, it should work fine for
your task. (Be sure to keep the abrasive grit from getting on the
surface anyway.)
A piece of glass perhaps 1/4" or 3/8" thick should suffice for
the purpose of adjusting the wedge. Remember to keep trying it
frequently for fit, or you could get too small.
Thanks.
I'm assuming that a jig wouldn't be needed to accurately remove
material equally along the length of the wedges.
If you have a flat surface on the wedge which meets the
dovetail's angles surface, you can probably simply slide that face flat
on some fine emery paper on a hard flat surface.
Yes, that's the plan.
I would still go for tuning the gap in the wedge myself. Or --
sell it on eBay and get a better one.
I wouldn't want anyone else to run into the same difficulty I have, so
I concentrate on fixing the problem.
* * * * O.K.
(I've also been following a thread on another site concerning a
related project involving someone making their own toolholders.
http://madmodder.net/index.php?topic=3206.0).
* * * * Interesting -- including the false start of wanting to make
holders of brass. *Bronze -- maybe. *Brass -- no!
BTW There has been a discussion of Shars tools on the local
metalworking mailing list, and the general opinion is that
they are very good -- with specific good reports on the
clone of the Kurt vises.
I have only corresponded with ne individual after seeing a thread of
his on one of these type vise, and he told me to run from the Shars,
and get the one from Little Machine Shop instead.(They were on sale at
the time and I didn't get my answer before the sale ended). His
message to me is as follows:
"I would turn and RUN from the Shars vise. Look at the cutouts in the
side, back near the handle, how ragged the casting is. Then look at
the key that aligns the fixed vise with the main casting. I would rate
the LMS vise out of the box at a 5 out of 10, and an 8 after rework. I
give the Shars vise a 3 out of the box and would fear having to
rebuild it. Just my honest opinion."
* * * * O.K. *Different opinions -- and I have not personally seen the
vise, but the owner (a local mailing list member) seemed to be very
happy with his -- after checking precision everywhere that mattered.
I'll go with what you said. That was only one response to my question
and I'm sure he didn't have a Shars in hand to really check anyway. He
was going by the picture in the site link.
Essentially, you are rotating a feeler around the center point
of the spindle and measuring how much it goes up or down. Since the
table is interrupted by the T-slots, something of precise thickness and
ground smooth (e.g. a bearing outer race) can give a surface for the
feeler to travel over without problems.
Ok. I understand. I'm considering something cheap(eBay) from
Shars(Discount_Machine): 330353712711
And as usual, 800watt, which sells the same tools as Shars is cheaper:
140419776972
* * * * Note that the first price is a buy-it-now, so you know what it
will cost while the other is a starting bid -- and if they have shills,
you may not get it for anything near that amount.
* * * * Shipping seems to be close to the same with the first being
shipped to my zip code, not yours (since I don't know it nor do I want
to know it) and the other a fixed shipping price.
Yes, shipping is close to the same. I've watch enough of 800Watt's
auctions end and wouldn't suspect any shilling problems. Many go
without bids and they come around again when re-listed.
Thanks a lot.
Darren Harris
Staten Island, New York.
--
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--- Black Holes are where God is dividing by zero ---
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. |
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