Member postings for old mart

You could buy one of those multisize keys and get an idea what the right size is.

There is no substitute for having a number of different taps in the same size. Unfortunately this is too expensive for most people. I have some Densimet which is a heavy sintered tungsten alloy. It is useful for making heavy, stiff holders for carbide inserts. It can be turned and milled, and even threaded for holding the inserts. I had to tap some 2.5mm threads in it, so I bought a couple of Europa tools green band taps. They are premium quality, but I had great difficulty tapping the densimet. There are several types of tap available in any size, and I chose the wrong grade. An old unidentified tap from the box of 2.5's tapped the densimet much better.

Welcome George, you will get used to every typo being a source of amusment, I try to proof read my posts, but miss a lot.

I believe that they will deal with the public, I bought a spare part for a digital micrometer some time back. You will have to register, even Screwfix does that if you order online. I wouldn't be surprised if the prices were less VAT and postage would be added. On page 10, there is a basic mechanical 150mm vernier with inch and metric scales at a price less than 24 euros.

If anyone fancies a good digital 150mm caliper which has imperial and metric, I can recommend the Tesa Twin Cal, I paid £90 for mine, an 00530321 which is as nice to use as my old Mitutoyo.

Edited By old mart on 20/04/2021 20:16:14

I bet some of the swimmers wished he was further out.

I wanted to make some special tee nuts for the compound on the Smart & Brown model A and a friend of the museum who did cutter grinding put the required taper on the end of a 1/2" four flute endmill. If you have a suitable donor cutter, then a small engineering firm could probably modify one for you cheaper than a special.

Emgee's suggestion of parallel slots with a tapered plunger would work very well if the plunger included angle was about 2 degrees.

My memory may be faulty, but many years ago when I bought an iris aperture for my Gamo 126, the man at Fultons of Bisley had a choice of 1/4 BSF for P H and 8mm, I had the 8mm.

I have this gear size calculator in my favourites:

**LINK**

You should be able to get close to a standard size, although small variations in the OD can be difficult to work out.

Edited By old mart on 18/04/2021 18:46:09

You could sell them on ebay as long as the listing was accurate, somebody might want them for resharpening. I would sell as a job lot at, say 50p each, and make sure your postage is covered.

TS use BA for the smaller fittings, so you could try a 2BA or 4BA screw in the holes.

Edited By old mart on 17/04/2021 19:53:48

I would also go for mild steel, unless you can get some SG cast iron. Cast iron is the messiest stuff to machine as the dust gets everywhere. The SG, (spheroidal graphitic, or ductile iron) is easy to machine not brittle and the swarf is nice, too.

Assuming you have only a small ammount of backlash on the Xaxis, say 0.01", 0.25mm, you can get away with climb milling using shallower depth of cut than conventional and applying a little braking from the locks. This is useful for the finish cut which will be smoother.

Thank you, Jason, for the clarification, I was indeed refering to threaded collets, the er collets have a range of usable sizes, although I would prefer to fit a 12mm shank in an 11-12 rather than a 12-13, for instance.

The screwed shank collets do not have any leeway at all, the difference between 16mm and 5/8" collets sometimes requires measuring the cutter shank to be sure

The spindle thread shows a lot of wear, but with a new backplate, the joint will be satisfactory. The front of the backplate will have to be trued up by skimming in situ.

If the size on the cutter is metric, you will need metric collets, and with inch/fraction sizes you will need inch size collets, they are NOT interchangable. That holds good for any variety of threaded collet.

No, the whole estate was built in the early 70's when a lot of gerry building was going on. It didn't even have an electricity consumer unit, I retrofitted one myself. Even the central heating is only 15mm in a large semi.

Good thought, Jim, I had forgotten my old Aquavac in the garage, it will make emptying the last water in the cistern and toilet bowl easy.

Dave, I just pulled the bath panel off to check, and my new connection is to a bend that is about 1" above floor level, so I might not have noticed at the time.

Here's a picture of a myford thread, it is not tapered.

**LINK**

I think Jason has the most plausible explanation.

Edited By old mart on 15/04/2021 17:41:42

Edited By old mart on 15/04/2021 17:45:13