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2mm work and watchmaker's lathe


bogieman

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My collection of watchmaker lathe parts is mostly stuff that doesn't go together. Is anyone else in a similar situation who would like to consider swops and exchanges to see if we can each end up with parts that go together to make some useful pieces of equipment rather than boxes of bits?

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  • 2 weeks later...

 

PS Do have a spare set of step collets/chucks or 4 jaw chuck? They're on my to be acquired soon list...

 

Yes I have a set of step collets spare and a box chuck although not a 4-jaw. In fact I've quite a few spare parts now that I've made up a decent setup from all the pieces I have. Let me know if you're interested in anything and I can send pictures.

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My collection of watchmaker lathe parts is mostly stuff that doesn't go together. Is anyone else in a similar situation who would like to consider swops and exchanges to see if we can each end up with parts that go together to make some useful pieces of equipment rather than boxes of bits?

I had wondered from your descriptions! each maker, both the Swiss and the British tended to try to keep the lathes themselves a bit different, but collets became standardised to an extent, 6, 8, 10 mm with buttress threads to allow for the drawbar pull.

 

The cross slides may appear near universal, but the main lathe bar beds differ, and if one is to be fitted to another lathe head stock ad bar, then may need attention to a re-bore to sleeve or bore it out to a fit.

 

Chucks tended to be the makers choice of fit, 12mm screw, 14mm screw and 20 were used, with British fitting the metric threads on most, to make sure other parts would fit. Some used the drawbar to pull the chuck in to the collet holder, some Like Lorch and Pultra have a Brown and Sharp Taper(not Morse), and a special courser threaded drawbar issued to secure.

 

Tapers vary a lot, B&S were common, Boley and Lorch had their own tapers as well, and rarest were Morse, considered an engineering type, not watchmakers.

 

Most collets are interchangeable, but check the threads with a glass, and see it it is plain, or buttress, the drawbar must match!! wear will allow one to fit another, but the wear will rapidly increase. Drawbars have to be made in a lathe, by cutting to form the buttress thread correctly, no taps are made to the thread form, (or at least easily found these days).

 

The threads of everything else are best turned, but taps exist for most including Unimat 12mm and 14mm, Tracy Tools have them in reasonable priced versions.

 

Box chucks are not liked by Engineers who expect a four jaw, but they were used to hold awkward blocks in watchmaking, like a case for instance, and always used brass packing under the screws, to jig hold the item without marking it.

 

By the way, the Chinese have moved into producing Watchmakers lathes, quite reasonable in price, and very complete. I checked over one and was surprised at the quality, and spares for these may be of use on older machines, as they are copy designs.

 

Stephen.

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Yes I have a set of step collets spare and a box chuck although not a 4-jaw. In fact I've quite a few spare parts now that I've made up a decent setup from all the pieces I have. Let me know if you're interested in anything and I can send pictures.

 

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Looking at my 8mm collets I've noticed that there's a variation in the length by about a mm or so and also in the length of the outer taper varies. Does that mean that some I shouldn't maybe use in my lathe? They tighten up ok but maybe not on a good mating surface in the bore. Any knowledgeable persons any good advice to give.

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They can vary a bit between the base of the cone and the screw area, that does not matter, the drawbar will still pull, the taper angle must be the same as the normal cone taper, but the length of the cone does not really matter, so some may stick out more than others.

So carefully check the angle of the cone, with a stock size blank to match the collet fitted, and gently draw the collet tight with engineers blue added to the collet throat, withdraw and examine the match between the collet and the cone, the blue will reveal the true contact area.

To save confusion I mean ENGINEERS BLUE, not MARKING BLUE, engineers blue is like fine shoe polish and is an indicator of fit to microns.

If you cannot find real engineers blue for sale then measure the angle, but this is not simple at home, but you can put a pair back to back to see a comparison with a known well fitting one.

Stephen.

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They can vary a bit between the base of the cone and the screw area, that does not matter, the drawbar will still pull, the taper angle must be the same as the normal cone taper, but the length of the cone does not really matter, so some may stick out more than others.

So carefully check the angle of the cone, with a stock size blank to match the collet fitted, and gently draw the collet tight with engineers blue added to the collet throat, withdraw and examine the match between the collet and the cone, the blue will reveal the true contact area.

To save confusion I mean ENGINEERS BLUE, not MARKING BLUE, engineers blue is like fine shoe polish and is an indicator of fit to microns.

If you cannot find real engineers blue for sale then measure the angle, but this is not simple at home, but you can put a pair back to back to see a comparison with a known well fitting one.

Stephen.

Well I'll try and find some of that but where do I start to look.

Reassuringly when I hold the slightly different ones end to end but taper siding against taper, if you get my meaning, they always line up in a straight line, so I guess the tapers are all the same, it's just some have a slightly different length (rather than angle) of taper and therefore ever so slightly larger heads.

So maybe they'll all be a snug fit when drawn in by draw bar and I'm getting overly concerned.

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The check you have done is what I meant, and is accurate as long as the collets are 100% un-strained or bent.

 

Never ever draw a collet without the stock size material in place, a drill shank will do, otherwise the jaws will close to much and may not string back to size. The best collets can stand some abuse, but cheaper ones may be un-hardened, or specials made in mild steel, to grind and bore accurately for custom sizes, and these could be ruined by drawing hard and crushing the jaws.

 

Schaublin and Boley etc are special spring grade steel, heat treated to exact hardness and spring, but even there, never draw without the stock size material fitted. Collets do not grip by pinching the metal, they merely grip by tight fit plus a gentle pressure, to help keep wear and tear to a minimum.

 

The amount of excess the jaw stick out does not matter, there are specials made with long jaws or expansion types for internal gripping etc.Some chucks are fitted on un-split collet fitting mandrills, and these may have long overhangs.

 

If it is a decent lathe mandrill, then the cone should be accurate and unworn, as these where ground in place, and heat treated to give a glass hardness that rarely wore. Check the appearance with a strong glass, it should not have a pattern matching the splits in the collets, it may just show faintly, but if there are wear ridges, then the cone must be re-ground.

 

This can be done in the lathe after the main bearings are serviced, tight, and true, with a suitable slip stone rod in the tool post, and the top slide set to the cone angle, using a good dial gauge to set the angle to match. The lathe is set running fast, and the stone rubbed gently back and forth to polish away the wear. An Arkansas slip stone rod is best, and the process is slow and steady, removing microns, not thousanths.

 

Japanese Ultra fine grade slip rods can be used, or ultra fine diamond paste and wood slips, but this requires a bit of experience! To finish "Stone of Air" slip stone can be used if you can find a supplier. This is like a soft soap stone, and is the mildest abrasive slip stone. Brasso applied with hard oak wood slips will work in the same way. The finished cone should look like well polished chrome.

 

A well set up Lorch Lathe, with the famous double taper bearings will produce a cone that even the best dial gauge with levers added, will not detect any run out. They are more likely to test the give of the oil in the bearings, or heat expansion effects, than run out.

 

Stephen.

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The check you have done is what I meant, and is accurate as long as the collets are 100% un-strained or bent.

 

Never ever draw a collet without the stock size material in place, a drill shank will do, otherwise the jaws will close to much and may not string back to size. The best collets can stand some abuse, but cheaper ones may be un-hardened, or specials made in mild steel, to grind and bore accurately for custom sizes, and these could be ruined by drawing hard and crushing the jaws.

 

Schaublin and Boley etc are special spring grade steel, heat treated to exact hardness and spring, but even there, never draw without the stock size material fitted. Collets do not grip by pinching the metal, they merely grip by tight fit plus a gentle pressure, to help keep wear and tear to a minimum.

 

The amount of excess the jaw stick out does not matter, there are specials made with long jaws or expansion types for internal gripping etc.Some chucks are fitted on un-split collet fitting mandrills, and these may have long overhangs.

 

If it is a decent lathe mandrill, then the cone should be accurate and unworn, as these where ground in place, and heat treated to give a glass hardness that rarely wore. Check the appearance with a strong glass, it should not have a pattern matching the splits in the collets, it may just show faintly, but if there are wear ridges, then the cone must be re-ground.

 

This can be done in the lathe after the main bearings are serviced, tight, and true, with a suitable slip stone rod in the tool post, and the top slide set to the cone angle, using a good dial gauge to set the angle to match. The lathe is set running fast, and the stone rubbed gently back and forth to polish away the wear. An Arkansas slip stone rod is best, and the process is slow and steady, removing microns, not thousanths.

 

Japanese Ultra fine grade slip rods can be used, or ultra fine diamond paste and wood slips, but this requires a bit of experience! To finish "Stone of Air" slip stone can be used if you can find a supplier. This is like a soft soap stone, and is the mildest abrasive slip stone. Brasso applied with hard oak wood slips will work in the same way. The finished cone should look like well polished chrome.

 

A well set up Lorch Lathe, with the famous double taper bearings will produce a cone that even the best dial gauge with levers added, will not detect any run out. They are more likely to test the give of the oil in the bearings, or heat expansion effects, than run out.

 

Stephen.

Gosh I am learning a lot of useful information, thank you for your trouble explaining all this. I have two further questions tonight one not related to lathes though.

 

1. Does anyone want to swop a duplicate 5, 10 or 18 collet I have as spares for one of your duplicates that I don't have?

 

2. Why is it that my computer opens up pages in microseconds, Yahoo Groups for example like the 2mm SA one, but no matter which computer I use RM Web can take 5-10 minutes to download and tonight it took 15 minutes to open, maybe longer. Is it just a question of lots of people being on the site of an evening at the same time perhaps?

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No spares I am afraid, only the Lorch set.

RM web is usually very quick now, do you clear temp files and cookies regularly?, I used CCleaner, a very safe free program. This does not remove passwords and such like, just unimportant files and cookies. Used daily it at least removes the daily trash files. It also has a decent start up control and a decent registry cleaner that works and is safe within reason, (back up is advised). Piriform also have a free "degfraggler" program which beats windows own every time!( you do regularly de-frag the drives I hope.)

Stephen

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I had a bit of experience with Schaublin lathes in rather poor state really, but accurate within reason, that had to take 1mm collets to grip 1mm stainless steel vacuum hardened centre-less ground rod, that had to have a 3.5 o taper of measured length, ending in a flat on the point of 39 to 40 microns dia, flat stoned by hand!! They were test needles to BSI standard to test another BSI standard, how hard Tar is!

 

The collets were worn and gripped at the back of the jaws allowing flexing of the rod under the pressure of the grinding, resulting in having to make multiple passes. (A custom Boron wheel was used to grind the points).

 

I had to get new Swiss made collets, and even these had to be hand honed to an exact 1mm to G/tee the jaws gripped parallel or faintly in at the tip end, to maximise the grip, without marking the 1mm rod.

 

Stephen

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Just used both programs, 590 meg removed in temp files from today, and registry checked about 20 items, it now loads in about 2 seconds at the moment, (20 meg Virgin, 2.8 meg Pentium D and 2 gig ram.)

Stephen

Yes I use C Cleaner fairly often but not daily and de-frag as same time. Will try Piriform tomorrow, will report back on that.

Have you heard of Victor or Dale collets?

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Victor were an American brand, good quality, and Dale were made by Hardinge Brothers in the UK. Swiss makes are meant to be the best, but the US and UK had major suppliers as well.

 

Sounds like the computer is OK, other experts may be able to put forward other reasons for slow loading.

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  • 1 month later...

Victor were an American brand, good quality, and Dale were made by Hardinge Brothers in the UK. Swiss makes are meant to be the best, but the US and UK had major suppliers as well.

Finally have my new watchmakers lathe set up and as trial turned a chimney and dome that I'm quite pleased with. Really impressive piece of kit for 2mm work.

Couple of questions, how can one tell makes of collets? Some have a sort of double "C" on them but mostly nothing. Some have slightly larger diameter heads and some there is a recess on the central part of collet face. In particular how can one identify modern Chinese ones that I'm told (not sure if it's true or not) are not hardened or so true from original Swiss, German US and other such makes?

Also I have about a dozen or more duplicate sizes (8mm type) does anyone want to do some size swaps? I find that you really need the exact size collet to get a good grip! One size either way is just not as good.

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Also I have about a dozen or more duplicate sizes (8mm type) does anyone want to do some size swaps? I find that you really need the exact size collet to get a good grip! One size either way is just not as good.

 

Sadly I do not have any spares. The learned gentleman that I acquired my lathe from advised that 1 size either way could be made to work acceptably. I have made sure than I have the sizes I use most. I have recently acquired a 4 jaw chuck from RDG tools (It appears to be decent quality but I haven't tried it yet) for doing larger pieces such as domes. Many of my collets have the CC marking you describe. I am not convinced they are hard though because a few have concentric rings on as if a previous owner has run the tool into the collet accidentally.

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Only as a general comment, but try to keep to the marked or tested size with wire collet chucks, they will not give a good grip when forced to close further than really intended. Engineering collets are different, and can take more abuse.

Lots of collets are supplied soft, to allow lapping the tips to an exact fit on the stock blank. Also to allow machining the front face to get clearances with the work.

I have not found the CC reference, it could be Burgeon or Boley, etc.

Early Chinese collets were renown for inconsistencies, but have improved rapidly.

Stephen.

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  • 2 weeks later...

I must say that having turned my first chimney and dome on my new watchmaker's lathe, holding the parts in a collet, has been an absolute joy. I thought it was going to be a nightmare but it's really worked out well although I think I could do even better with another go. In fact having flycut the base of half a dozen stubs of brass and nickel silver I'm thinking of making a batch to go into stores just for the pleasure of making them!

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