Member postings for old mart

That modern advert for the chuck had a clue in it. Did you notice it was intended for woodworking?

I have one of these MT2 Autolocks in a wooden box, but have never tried to turn that sleeve, so I had no idea that it was multi start. I suppose it could be tightened as much as possible when the Autolock was being removed, to assist the tapping of the drawbar, every little helps. Just make sure it is backed off when refitting so that it doesn't interfere with the proper tightening of the MT.

I milled flats on the thick part of the er25 collet holder that I bought some years ago using a solid carbide end mill. If you buy one now, it will probably have flats on it already.

You can buy MT2 collets which hold metric cutters directly, I'm not sure how large they go.

Edited By old mart on 29/04/2020 21:37:33

The jaws were probably ground with a very small wheel, which results in the sharp edges touching first on anything of larger diameter than the grinding wheel. Assuming the four jaw is independent, removing the edges would not be likely to spoil tis accuracy. I would put a sheet of 1000 paper on a flat surface with a square sided block on it. Then I would give each jaw in turn one light stroke longitudinally resting against the block. Try to make each stroke of each jaw as equal as possible, using a fresh part of the paper for each. Wash the jaws before re fitting them. It would be a good idea to keep each jaw in its original slot. This might be too slight to notice any improvement, but better safe than sorry.

The numbers don't make much sense, M5 is very close to 3/16 BSF, very slightly bigger, 0.197" as compared to 0.1875". Perhaps it is one of those old proprietary threads used to stop unauthorised repairs or something from the firearms industry.

I used to have one, I never quite got the hang of getting both drill flutes identical.

Funny that the patent illustration shows jaws with a square hole which is more logical.

It is a clever design using a hurth coupling to align and spring loaded balls to hold the post while the coupling is being tightened down. I think the post can also be locked in any of the angles allowed by the number of coupling teeth. Differential threads in the central column and at the bottom of the toolpost lock and unlock the post. The internal parts which have to be realigned are marked as such.

Sorry, I forgot that their new format won't allow viewing unless logged in, I hope it can be remedied.

Here are the pics:

See the ninth post in the current thread " getting a milling machine ready for use".

The wear in the bed of the museum's Smart & Brown model A is so great that I opted to have the saddle extremely tight at the last three inches at the right hand end. It doesn't get used there often.

If anybody is interested, I have succeeded in getting the toolpost to bits, pictures of its guts here:

**LINK**

The standard Light vertical has a 1/2 hp motor, 0.38kw as Steviegtr mentions. The Museums drill mill has a 1 1/2hp motor which is one of the reasons for the modification.

 Taking the quill spring out is a pain and if it feels smooth without disturbing then leave well alone.

Edited By old mart on 28/04/2020 15:38:46

I didn't mention anything about changing the spindle in this thread. I was in the fortunate position of having a big enough lathe and a mill to do the work. Not many people will be able to do it.

With MT2, I would get an er25 collet which goes to 16mm diameter. These usually have 10mm threads for the drawbar rather than the original 3/8 BSW. Getting 10mm studding to make another drawbar is easy, although during lockdown it could be by post.

The belt looks fine to me. The autolock looks like the type with the left hand threaded ring at the top which you snug up against the spindle after tightening the drawbar. This stiffens the rather small and flexible MT2 fitting. Check the autolock collets, if they are marked in fractions, then use inch size cutters, and if they are marked in millimetres, then use metric cutters.

The belt looks fine to me. The autolock looks like the type with the left hand threaded ring at the top which you snug up against the spindle after tightening the drawbar. This stiffens the rather small and flexible MT2 fitting. Check the autolock collets, if they are marked in fractions, then use inch size cutters, and if they are marked in millimetres, then use metric cutters.

That is the body of a Clarkson Autolock in the spindle. It is missing the end nut. It will have to come out, just slacken off the drawbar about a couple of turns and hit the end with a copper, or aluminium headed hammer. Your spindle takes Morse taper 2 tooling.

I have solved one part of the puzzle, the threads underneath are 5/16 UNC. I made an impression of the threads and found the pitch to be approximately 16 to 18 tpi. That definitely narrows it down to BSW or UNC. I had tried what was probably a BSW bolt without it screwing in, but today I had another search of the garage and found a bolt with the nuts on it. The nuts were too small for BSW so it is probably UNC. It is a tight fit, but screws right to the bottom of the hole. Not being able to get to the workshop at the museum because of lockdown is a handicap.

I still will need to strip it down before deciding what to do with it, the rear toolpost for larger boring bars is current favourite, it will be much stiffer than any standard one can be, and 25mm left hand bars will fit it.

I will be asking about this toolpost on the Home Shop Machinist to increase the chances of somebody recognising it.

Here's another more sophisticated one with an er 20 collet, even more power and speed.

lUAAOSwYVRcxsD4">https://www.ebay.co.uk/itm/EU-2-2KW-ER20-220V-Air-Cooled-Spindle-Motor-2-2KW-HY-VFD-Inverter-Driver-400HZ/383501508816?hash=item594a78a0d0:glUAAOSwYVRcxsD4

I have seen high speed motors with er collets on them on ebay, I wonder if one could be attached to the head or quill of a mill when the very small cutters are used? I found this on ebay with an er11 collet which goes from 2000, to 12000 rpm.

https://www.ebay.co.uk/itm/400W-CNC-DC24V-52V-High-speed-Air-cooled-Spindle-Motor-for-Engraving-Milling/221839037678?hash=item33a6a314ee:g:V2cAAOSw3ydVuEMh

Edited By old mart on 26/04/2020 18:50:15

More likely forgings or extrusions. Still you now have some swarf to throw out.