Making WW 8mm collets in the home shop. How would you do this?

[BCRider]

I've had a semi working watchmaker's lathe for some years now and thanks to a member's kind generosity I now have a three jaw chuck to use with it.

This has encouraged me put some time into it and make it more functional for use in making smaller size parts. I've used it for a couple of small "wire size" parts in the past but it was never fully and properly functional for regular use.

The one thing I'm shy of is the WW collets that can be used with some common sizes of stock that would be suitable on this size of lathe. Like 1/16 to 1/4 diameter sizes in 1/16 increments. And since I'm in Canada where we are dimensionally confused perhaps a second set of metric sizes in similar steps. from 1.5 up to 6mm.

Used collets are rather pricey from looking on Fleabay. Sherline makes and sells sets or individual WW collets. And while not HORRIBLY priced I'm still looking at up near to $300 or so of my Kanukistan Kopeks for 5 each imperial and metric sizes. And that's enough to encourage me to at least have a go at trying to make a couple. And if it works out to try making them in tool steel and harden and temper them. The final fit on those then being lapped in using suitable sized brass laps and fine abrasive.

So anyone make collets in this size? Thoughts I should be considering? Would they be durable enough if made from something like 4140 pre-hard and skip the heat treatment when used in a home hobby setting?

[J Tiers]

That IS high. I got about 40 of them thrown in with a jeweler's lathe which I bought for quite a bit less. Dunno why you would need any inch sized ones, the metric sizes cover a lot of ground, in 4 thou increments (1/10 mm). They have always fit for me.

No reason you could not make them. I plan to make a few larger sized "wheel collets", and probably some other tooling to fit the spindle.

The trick seems to be to leave a ring "nose" on the collet, split it without cutting the ring, do all the heat treating, then grind that off as the last step to release the split collet. I have not done it as yet, but that is the plan I would follow. Came from a reprint of articles from an ancient machinist magazine.

[mickeyf]

BC, I have an entire watchmaker's lathe with a bunch of collets that someone in Ontario did not end up buying after I packaged it up for the Post Office to give me a quote on for shipping. The lathe itself needs bearing replacement, but if you think there's a chance you'd like the collets enough to take the whole thing for what I was asking ($200 cdn), PM me and I can send what info I have. (Another project? Just what you need 😂) I never get to the Mainland, but if you're over this way...

[BCRider]

JT, that's a solid gold bit of information. I'll hold that in mind.

Mikey, PM sent!

Thanks to both of you for the idea and the option.

[ammcoman2]

I bought an ER11 collet chuck with an 8mmm shaft for my watchmaker’s lathe. Then whittled the shaft into a WW collet.

CTC in Hong Kong (I think) has excellent quality ER11 collets so I bought a metric and an imperial set.

Happy camper.

Geoff

[Paul Alciatore]

I have a Unimat which is similar in size to a watchmaker's lathe. When I decided to get some collets for it I looked into the OEM collets and watchmaker's collets. Both came in English and metric sizes and each size covered a diameter range of only a few thousandths of an inch, five at the most but more like two or three for the smaller sizes. Then I looked at ERs. The ERs each cover a range of about 1 mm or 40 thousandths. A set of seven ER-11 collets covers the full range from 1.15mm to 7mm with no gaps. That's 0.045" to 0.275" or 1/32" to 17/64" - slightly over 1/4" on the high end. All with no gaps in the grip range.

It would take about 46 watchmaker's collets to cover that range. I paid a bit over $100 for a set of new ER-11 collets and an ER-11 collet nut. I made the collet holder myself. It is a lot more economical this way. As you have discovered individual collets, even small ones, can be quite costly. Of course that was around 12 years ago and prices may have risen.

My set of ER-11 collets is the Iscar, ETM brand, made in Israel.

[epicfail48]

Would they be durable enough if made from something like 4140 pre-hard and skip the heat treatment when used in a home hobby setting?

I was actually going to suggest doing exactly that, until i read to the end. I cant imagine any reason that 4140ph wouldnt work, as youd want the collets to be tough and springy more than hard, and that steel fits the bill just fine. I know that my er32 collets are hardened, but definitely not super-hard, as incidental contact with tools has proved...

[Mcgyver]

the good ones (all used, you can no longer buy Schaublin, Boley, Wolf Jahn, Rivett, Perless, American Watch Tool (whitcomb) and many more) are not much, not remotely enough to warrant making them, which would be a considerable challenge. Because the work can be so small, they are finely made and runout is about negligible, likely a tenth or better on most. Hard for us weekend warriors to achieve that in hardened material....all to save around $20 (each).

While an ER collet might be just thing for your intended use, its not going to compete with a spindle mounted quality collet in terms of accuracy which would really matter if you are turning watch parts, or watch sized parts.

For their intended use one needs a set or at least a good selection, as you never know what size of work you'll be holding....but if you are just intending on turning stock sizes, as you suggest a few should suffice. There often seem to be sellers on ebay selling individual ones.

The vast majority made are metric and are graduated in tenths of a mm. Just get the closest sizes.

The threads are widely interchangeable but are not universal, so there is a chance of something not fitting. Also, be aware the Starrett collet maker is not L.S. Starrett. Starrett collets are regarded as low end, unhardened, so don't pay a boley price if that's what you stumble over.

I have probably a dozen in rough shape that'll send you for postage. They will work but you will likely have to lap the ID's to clean them up.

With Mickey's package, if you take it, I might be a buyer for extra pieces (or the package if you don't take it)...I have a few project one's here missing bits and pieces. IMO bearing replacement is about impossible for a whole bunch of reasons around the geometry and the special equipment needed, but maybe there is a needed TS or accessory.

Let me know if you want the ones I have, postage shouldn't be much.

cheers

[J Tiers]

New collets are "available".............................

You can get a small set of WW collets new from Louis Levin & Son, Inc, for a mere $6500 for a set of 16 in 64ths of an inch. What a deal!

Their cheapest individual collets are only $500 each. If you want square or hex, the price is slightly higher at $1500 each. Very small are more expensive, at $3500 each.

For your ordering convenience, here is the price list and availability:

https://levinlathe.com/page23b.htm

[lynnl]

...or their p/n 0361-03 (89 collets) is only $41,000.

At those prices I imagine Louis Levin & Son are working round the clock trying to keep up with demand. So there will probably be a lag time before you get them.

[old mart]

I would favour the er11, or maybe er16 conversion, you can get industrial quality for much less than what you have already.
We have lots of Smart & Brown model A spindle fitting collets with 3 cuts, most of which have seen better days. I selected some of the most worn ones, shimmed the cuts and bored them bigger with solid carbide. Now we have 6, 8, 10, 12, and 16 mm plus 1/4", 5/16", 3/8", 1/2" and 5/8" with good true running bores.

[BCRider]

I'm shocked that Levin is still in business with pricing like that. It certainly takes things up to the level where only commercial companies could afford the costs.

Yesterday I saw some references to Sherline having 8mm WW collets. Sure enough! The have SMALLER SETS OF 5 COLLETS in both imperial at 1/16 to 5/16 in 1/16 increments and 2mm to 6mm in 1mm increments. Separate collets are also available. But the cost of the set with the drawbar and knocker is less than the cost of the individual collets! ? ! ?

These sets, the imperial in particular, would do what I'm after by giving me a way to hold the K&S brass rod in those sizes along with O1 annealed drill rod as stock on the steel side of things.

Of course the cute little 3 jaw that gratefully came my way will play a big part in all this. It'll be extremely handy when using the compound tool unit. But I'd like to try my hand at hand turning with gravers. And I'd rather not have to deal with the spinning jaws that close to my delicate digits.

I'm going to check the runout with a few size pieces. But right now I've got it in my gun cleaner bath of Ed's Red since the old oil seems a bit sticky. Or it might even be NIB without the box and still have that slightly odd preservative greasy oil that can often feel less lubricative.

[BCRider]

Oh, as for the idea of the ER chuck spindle. I actually thought about the idea of doing an ER spindle. But this is the style with the dual taper hardened steel on hardened steel bearings. And I'm sure there was some lapping to fit or some very fancy fitting at the factory. I won't say it's not possible in the home shop. But it would certainly qualify as "fiddly work" to match up the tapers that precisely.

[J Tiers]

Those Sherline collets are only "specified" to a couple thou runout...... "These collets have a maximum runout of .002″ or less.".

They start at 0.3mm hole, which is 12 thou. That means the runout limit is 17% of the diameter of the part. Not too wonderful. There are things which you pay for with the ridiculously expensive collets, although Levin curiously does not specify a runout.

If you make your own, there is no reason you should not do better than that 2 thou, at least with collets larger than the minimum size. Making the very smallest is an issue, as the slits alone must be much smaller than the hole. Then also, getting a very small hole on-center is tricky to say the least. Lapping that small hole to size and measuring it is even more "interesting".

But from perhaps 1mm and up, it seems do-able with decent accuracy better than their 0.002". I've made a 3C collet adapter with essentially zero runout in the original position. Given that most jeweler's lathes are really quite accurate, it ought to be quite possible, if the holes are done when the blank is in position in the lathe..

[BCRider]

I saw that too. Not all that promising at first read. I'm hoping that they typically do a lot better.

I'm going to ponder what would be needed to do a nice mini production run for a few sizes. Clearly all the outside features would be done in one hold to ensure concentricity. Off the top of my head I'm thinking.....

1. Face end, extend out for collet length, center drill and support with tail stock.
2. Cut parallel and nose conical features. Prep thread area.
3. Cut thread from shoulder to tail with upside down cutter running in reverse.... Tail stock is in the way for a rear side right side up tool.
4. Back off tail stock and drill larger size clearance hole.
5. Part off the blank.
6. Rinse and repeat as needed.

After that was done I'd use a 5C emergency collet bored to size to hold the parallel portion of the collet. This should ensure pretty good concentricity as by hook or crook my 5C holder runs with less than a half thou runout last I checked. And what it does have is very consistent. So the emergency collet should be able to hold to a couple or three tenths... I hope.... At that point it's clean up and dome the nose then drill and ream for the sizes. For really nailing the center mark to guide the initial drills I'd fuss over the tail stock centering. And I might even do something to get me a better small drill holding setup.... I'd need to give that a bit of thought.... It would be a setup that was drilled to hold the chuck of some manner directly by the lathe spindle. So it would be dead true. I'd just need to include a way to ensure it was able to be re-clocked when using it each time. Seems like a good job for one of the soft nosed MT2 blanks I've got.

After all that the slitting saw and a very small V ground graver like tool to clean away any burrs. We're talking 1/16 as the smallest. So fairly practical.