Member postings for old mart

I can think of quite a few dating back about 20 or 30 years, but not one now. Same thing with motorbike shops, Pride and Clark, Commerfords, Deeprose, Gus Kuhn, Stratford Motorcycles, Harold Daniel, Elite Motors, and George Brown, to name but a few of the London shops I knew.

They are good if you manage to actually get to talk to a human being.

 They might be in for a hard time in my area, green marks have appeared all over the pavements, and cabling for Virgin is being laid only a few streets away. I might get more than 8mbits in the near future.

Edited By old mart on 10/09/2019 16:41:10

I would have used white spirit, myself. When I chose Plastikote paint for the Tom Senior, it was a gamble whether it was oil proof. Fortunately, a test on a bit of scrap metal was ok, but I would be wary of spray degreasers. The local hardware shop has two types, brake spray, and carburettor cleaner, the latter is much more aggressive towards paint.

I expect you are thinking of the old LOO type of spindle fitting, which is a taper, woodruff key and a threaded locking ring. 

 There are various improvements that can be made to your new lathe spindle. it certainly has the advantage over threaded spindles if you want to run in reverse.

Edited By old mart on 10/09/2019 16:33:26

Jason B, the bearing inner of the top bearing on that type of mill certainly has to move to take up the slack, exactly the same as the lathe in the thread. Changing to taper rollers from sealed ball races is a good idea, but sealing the taper rollers is slightly more of a problem.

When I changed the spindle size on the Tom Senor mill, I designed in a double lip oil seal for the bottom taper roller, not to keep the grease in primarily, but to keep the swarf out. I didn't fit the garter spring.

As I see it, the front bearing is fitted to the headstock, pressing on the outer race and the assembly is then pressed onto the spindle, pressing on the inner race. Then the rear bearing is pressed onto the spindle until the outer race is up against the rear shoulder. It is important that both races are pressed as a unit. The fit of the rear bearing on the spindle should be a very light press fit which will ensure that the front bearing is not overstressed. I would support the headstock while the rear bearing is fitted. If thought is not applied to the assembly process, then brinelled bearings will result. Taper rollers would be easier to fit than the deep groove sealed bearings used on this model lathe.

Check that your lathe has the mill attachment on the back of the bed. I remember adverts for that type of lathe which came with or without the mill attachment, and there was a warning that the plain lathe could not be retrofitted with the mill.

 If space is at an absolute premium, then there is no point in trying to point you in the direction of a separate mill.

Edited By old mart on 09/09/2019 19:54:51

An old lathe chuck mounted on the table of a pillar drill would hold the bar stock while the drilling was done. If the drill can be run slow enough for the larger drill sizes, they would cut much faster than a diamond core drill.

Damn, I missed that!

My only experience of machining ductile iron (SG) is in modifying lathe chucks, and I found it so much better to machine than mucky, dusty regular CI.

Loctite bearing fit would certainly cure a loose bearing, but in this instance, the fit needs to be just tight enough to be easily adjusted, but not loose. Bearing fit Loctite would be too much of a good thing.

The collet question which has been somewhat neglected during the thread might be cured by using one of the collet plates which bolt directly on to the spindle flange. Like this one:

**LINK**

What matters is what the diameter started at and what size you are aiming for. I would not reduce the diameter more than 0.012mm, or 0.0005" at most. You have the old bearing inners to test the fit, they should now be noticeably easier to press on and off the rear end of the spindle than when they were originally removed. Tighter than a push by hand fit.

Boring out to 20mm would really require a 3/4" drilled hole to start with. Have you thought of a bench mounted pillar drill to compliment a small lathe. I have a 7 x 12 mini lathe at home, and it struggles to drill 1/2" holes in mild steel, even in the low gear. It would be fine for the finish boring and parting off.

You would do better by looking for a chuck with two sets of jaws, rather than reversible. There is one Pratt for sale at £215 on ebay, if you want guaranteed quality, but you may find the Chinese ones ok.

https://www.ebay.co.uk/itm/PRATT-BURNERD-100mm-3-JAW-CHUCK-FRONT-MOUNTING-HARRISON-COLCHESTER-LATHES/202200564258?hash=item2f1417c222:g:gUYAAMXQY8JRicph

This does not include the backplate, of course.

Edited By old mart on 09/09/2019 13:42:35

Edited By old mart on 09/09/2019 13:44:24

Your 2 axis DRO plus digital on the Z axis is the best compromise for a drill mill, go for it.

Be careful with the amount of diameter reduction you use, these small size threads don't have much to spare. I use these thread charts on the Motalia website, they show the thread depth.

**LINK**

Edited By old mart on 08/09/2019 20:34:18

Don't go overboard with relieving the fit of the bearings, they weren't designed to be sliding fits. You could easily end up with a scrap spindle.

As DG1 has already mentioned, it is important that the bore of the diestock is loose enough on the die to allow the die to be opened up for the initial cut. For that small size, about 0.2mm difference in diameters. A slight lead in chamfer helps, as does using the face of the tailstock chuck (with the jaws retracted) to keep the diestock square. A little cutting oil should be used. If you still cannot get a reasonable thread, the die may well be to blame, there are a lot of poor ones out there, and persisting with one of them is like polishing a turd.

The fortunate thing about owning a Myford is that all the parts are available, second hand or new. Secondly, the knowledge base is huge. I have never seen a manual chuck made by Kitagawa before, they specialise in top end power chucks for cnc machines.

It looks strange, as though the axels pass through the boiler, I think I would have rejected it too, if I had ordered a shunter and that monstrosity turned up.

Swedish made top quality steel. The iron wire is commonly used for holding things together while they are being brazed or silver soldered. The piano wire and the hard steel would be of interest to horologists