Member postings for old mart

I have just googled "lathe leadscrew guards" and one of the hits was just the ticket.

**LINK**

The curved sine bar that I mentioned must have had a very specific use, probably inside a matching radius, nobody either side of the pond has ever heard of the like. I now have difficulty remembering what the radius might have been, possibly 3 to 6 feet.

I would run the solid carbide drill, preferably a stub, at slow speed, by hand. A flat would be an advantage if you can be sure it is perpendicular to the axis. Solid carbide drills come in various types designed for different hardness steels, I would look at the drills from Cutwel, or APT.

If using a lathe, with the ball held in a collet, you could hold a diamond lap square in the toolpost and use the cross slide to rub a flat on the ball. It would take some time depending how fine the grit was.

Edited By old mart on 06/06/2021 20:24:46

I have small direct debits to the two local air ambulances and Great Ormond Street Childrens Hospital, there were others in the past, but when they started getting greedy, I finished with them.

It would certainly be possible with imagination to make one to suit a lathe, these things are available to buy, but are very expensive.

I have used blunt taps and also a length of studding, an electric drill with reverse, a ring spanner, and bingo, the nut is not quite as stiff.

You will probably need to buy a quality regulator like a Norgren and connect it downstream of the one on the compressor. The compressor regulator could then be turned up to a pressure range it can cope with. 1 bar is so low that the spring in your regulator is close to being unloaded.

https://www.solenoid-valve.world/category/48?gclid=EAIaIQobChMIgqSrsq-B8QIVBsPVCh0VlwyqEAMYASAAEgLhxPD_BwE

Edited By old mart on 05/06/2021 21:52:08

A seller on ebay had a pair, a 5" and the 2", made by his father, I believe. The little one is good in confined spaces. There was already a 5" at the museum and another 5" one was with a box of slips that I wanted.

Back in the 70's a sine bar was found in a job lot of stuff which the boss had bought. I had never seen one back then, but it was memorable, and one of our apprentices told me what it was. The bar was curved, not straight. It got binned, nobody wanted it. It was quite big, about 9" long.

Looking on ebay regularly under metalwork lathes, I see a large number of Myford gears of all sizes always on sale.

I have a serrated jaw chuck for when precision is needed and the 4 jaw independent is not ideal. Of course, the soft jaws have to be machined up every time, and getting the exact size without a three point bore mic is a bother. I have turned up a stepped gauge in the past when boring the jaws when the best fit is needed. With that chuck the master key that I find easy to remember is the one nearest the round label.

Edited By old mart on 05/06/2021 19:38:53

My RE Constellation, and Intercepter both had Lucas mags with the kill button wire connection in the centre of the end cap. I just used a press to make button on the handlebars. Not all mags had the stop facility, it might have been an extra.

Over the pond, Lucas was referred to as "the prince of darkness", although the worst electrical system I had on a motorcycle was on a PUCH 125 by BOSCH.

Edited By old mart on 05/06/2021 17:56:36

You should check if there is movement when clamping, and if it is measurable then use the clamped setting, as you would when using centres. Drilling is not so exacting, so that doesn't matter so much.

I have an update from preparing a 160mm three jaw scroll chuck for jaw grinding. Firstly, I modified the backplate for the lock to make running in reverse safe. After that was done, I skimmed the front face, it had 0.001" tir wobble. The chuck got dismantled and cleaned in the parts washer. The jaws were drilled in two places each, 6mm x 10mm deep with a solid carbide drill. The steel is surface hardened, but still quite hard in the core. The chuck is one I bought cheaply second hand, but it had never been used. I think it is of Indian origin as the jaws seem to be Bison dimensions, not the K11 design.

Before doing anything else, I got the main body running true, and then tried out three sizes of ground barstock. Smallest was a 16mm od test bar, then a 1" od MT capstan lathe socket, and finally a 55mm size. I couldn't find anything bigger, but not too big.

The results have been remarkably consistant. All three sizes using all three sockets gave 0.003" or slightly less runout with the high spot always in the same place. So far, I have only checked the inside of the inside jaws. It should be pretty good after grinding.

Since there was no definite best socket, I will use the one marked with an O.

Edited By old mart on 05/06/2021 17:37:22

Edited By old mart on 05/06/2021 17:39:19

I think it is because the seller uses a tape measure during the listing. I now have three 5" bars and a 2" one. I use one almost annually.

I have seen them on ebay with the overall length listed.

Edited By old mart on 05/06/2021 17:12:54

The tailstock of the Smart & Brown model A at the museum is the common type made from 2 parts to allow offsetting for taper turning between centres. To get it pointing along the axis, we had to shim the joint, with the shims tapering fore and aft to get the quill horizontal. Fortunately, the quill was in line viewed from above, so the adjustment for that was straightforward. The quill axis is 0.002" high and everything is locked because the offset is never used. With a taper turning attachment, the need to offset the quill is not likely to ever be needed. I have toyed with milling the faces of the joint and then using a thick shim, but have never had the nerve, as the tailstock is better than most as it is.

Iforgot to add my latest telescopic magnet with built in light from Lidl.

I tried out an online trigonometry calculator with a set of common measurements where those laser or ultrasonic measuring devices might be used for and the results surprised me.

Measuring a 16 foot room and pointing 6" off of dead square would have an error of plus 0.093"

I can only think that somebody has assigned that code to a particular type of nut and that "freecut" has no particular meaning. Look at the long strings of code at the top of each page when you are online, it is only an index.

The DT Swiss stainless bike spokes are stronger and harder than the stainless spokes from the 50's and 60's, but not so hard that they won't run through a thread rolling tool if their length needs adjusting. I have a stock of them which gets raided for little jobs occasionally.

Do you have a key for your safe, Ady?

Edited By old mart on 04/06/2021 16:14:58