Member postings for old mart

A directly screwed on chuck will normally save a bit of overhang adding slightly to the length of the bed, useful on smaller machines.

As Andrew mentions the drawback of directly threaded, I bought a NOS Toolmex 6" four jaw independent lightweight chuck threaded for Myford. The centre got bored out to max size and a Smart & Brown 1 3/4" threaded backplate fitted. Myford lovers will be issuing a fatwa against me now.

Edited By old mart on 09/10/2022 15:51:49

Seems like everything has been suggested, but I would check if the leadscrew rotates smoothly by itself without any end float and shows no sign of being bent. You could try different leadscrew gears if you have any and see if the pitch of the banding changes. Suspicions of the pitch of the leadscrew matching the banding have already been posted.

Keep us up to date with results as you go, the information is valuble.

I have two of Indian origin,a 7 1/2" and an 11 1/2", both with a MT2 end. After turning a 60 degree end on a steel 3/8 bolt in situ and checking between centres, the results were dissapointing, over 0.0005" tir. Then I realised my mistake, using a live centre in the tailstock. With a dead centre, the runout was affectively zero using a Baty 0.0001" DTI. And that was either way round for both bars. There are lots available now, including plain cylindrical ones. I don't know which company made them or even if they come from the same one.

One of those tools which I will get around to making one day. I had to make one once, but it was a special shape and not much use for general holding.

When our factory was in Guildford, there was a large early type cnc lathe and the guy operating it put an 6 foot length of 2" diameter aluminium in it without a bar feed and turned up the speed. The 4 feet overhanging the headstock bent and hit his toolbox and everything in it embeded in the ceiling about 25 feet above. Just as well the lathe weighed about 5 tons, it survived the hilarious incident. When the building was demolished, somebody might have found some tools. The lathe was sold and ended up in India.

I have just googled "Bosch X lock" and now realise that the discs are indeed proprietry. I would guess that Bosch are hoping that other manufacturers will take up the system, rather like SDS which is now a standard. There were plentiful supplies of the X lock discs available, but not much chance of getting one of the bargain grinders from Screwfix, there seems to be no stock left. Makes me suspicious that the whole X lock system is a dead duck about to become extinct, seeing the price.

Probably the flanges are a slightly different alloy composition, and higher up the electrochemical series.

When you get the lathe repaired, you may be able to get hold of one of the 3D printed gear locking devices to fit on the large gear nearest the front of the spindle. Using one of these spreads the force of unscrewing the chuck over many teeth. No more broken teeth. The lathe model and number of teeth on that gear would be required before ordering one.

The rough movement of the more recent ones is the problem, the slideways look like they have been hand ground by a monkey.

Most of the trouble I have had is not with the hard plastic parts, but the soft rubbery handgrips deteriorating. Sponge can also turn into nasty sticke powder, linings of Mitutoyo and Moore & Wright instrument boxes come to mind, plus light sealing in film cameras.

Edited By old mart on 02/10/2022 19:28:17

Thats what I was taught to do, no acids and should only take a few minutes, just a wire brushing before rinsing and drying.

Edited By old mart on 02/10/2022 19:19:05

I have just remembered the term for the dished discs, it is "depressed centre", easy to get hold of. My old Royobi uses them and can manage 125mm as well. A quality machine made in Hiroshima, not China, and not at all radioactive.

Ady, what do you think of the quality of your new calipers?

Edited By old mart on 02/10/2022 19:03:07

I have never heard of an angle grinder that uses non standard 4 1/2" discs. Normally there are only two types of this disc, the plain and dished which are freely available.

I wonder if anyone has bought two gears of the correct specs and joined them together to make a cluster?

I noticed that, but I already have 3 of them and there is something that I have noticed also. The first one is still in use, excellent value, but the successive calipers bought about 3 years apart are mechanically inferior, while being electronically more advanced. That was enough for me to transplant the reading head from the last one into the body of the first. They are not in the same class as my Mitutoyo or Tesa, but only a fraction of the cost.

How about Warco, about 11 miles South East of Guildford Surrey.

Edited By old mart on 30/09/2022 17:53:23

Why not a washer under a flat plate?

I have a 7 x 12 which I bought second hand with a vertical milling attachment. This didn't work well mainly because the attachment was not on the centreline of the spindle, being attached where the compound fits. I have seen ready made adaptors on ebay which address this offset problem which would allow milling up to about 3" to be done

Probably not, I thought star was for 440V and delta for 240V, no doubt the experts will enlighten us.