Member postings for old mart

The rubbish spouted out in the sales blurb is not aimed at intellegent people, but at those who have lots of money and who are easily fooled into thinking they are helping the planet.

The threaded joint between the arbor and the head is the strongest part of any boring bar. The weakness is in the moving parts and the fixing of the tools to the head.

When I worked as an instrument mechanic, my firm had three lathes, a watchmakers lathe, an ML7 and a new Super 7 longbed. They spanned the sizes of things that we needed to make perfectly. They were never intended for heavy production use, leave that to the DSG's and capstans. Our Super 7 would chuck things up to 0.0005" in its new Pratt chuck, and the nearest thing to large scale work it ever did was about 200 small steel pins held in the lever operated collet chuck. The only thing against Myfords today is that they command a high price, and not all of them are worth it.

I had the toolmakers make a special rod for my Mitutoyo 0-6 depth gauge, somewhere in between the 2" and 3" rods. This was used to measure the stroke of a hydraulic cylinder used on Airbus main landing gear and landing gear door uplocks. Otherwise I would have to changed rods each time the stroke was measured even though the stroke was less than 1". I still have it, not much use now.

 The 2.675" will be the length of the 0-1" rod from the tip to the underside of the top flange. Add 1" to that for each successive rod. Not easy to adjust, fortunately rarely required.

Edited By old mart on 02/03/2023 20:54:51

Edited By old mart on 02/03/2023 20:56:25

If you can make the hole without any swarf getting into the mechanism, and sure that when oil is used that it does actually lubricate the intended parts, then go ahead. I believe that anything you can do to improve the design and function of something is worth doing, better than the polish and paint makes pretty brigade.

Good luck to you with the blending, the difficult part would be getting the crown symetrical, so the belt will naturally stay in the centre. perhaps only actually running the belt will tell you if there is a tiny bit more filing needed on one side, the side the belt moves away from.

I would do it the hard way for lack of suitable machinery. First find out exactly what the crown dimentions were. Then turn the pulley to the maximum diameter of the crown. The diameter of the outside ends would be done with a narrow grooving tool. With a fairly narrow pulley, that would give a reasonable start for hand filing of the profile at low rpm using the back gear. The difficult part would be to make the crown symetrical.

The 1 1/2" x 8 spindle size is used on several lathes both in the UK and in the USA. Atlas definitely use a 60 degree thread, but do the British makers also use it or Whitworth form? Could somebody with a Boxford tell me which thread their lathe uses?

Very nice drills, shame that quality is not cheap, though. I find that high pressure and slow speed works best with stainless steel.

I bought a 100mm four jaw independent to fit on my 7 X 12 and modified the body to suit the spindle flange. The original mounts were rear, but there is no reason not to drill the body if necessary for front mounts. The register had to be changed to suit in my case.

I have a few threaded shank endmills of German origin which have carbide inlays brazed to the steel body. As I cannot sharpen the usual hss threaded shank cutters, they are only used on aluminium, and solid carbide in er collets used for steel or indexable cutters if possible. I have made a 16mm threaded arbor for small slitting saws which comes in handy.

Edited By old mart on 24/02/2023 15:52:33

Edited By old mart on 24/02/2023 15:54:43

I recently took a chance and bought a 5-20mm keyed chuck with an R8 arbor to use it on for £36.50 from RDG. The finish and runout are excellent for a cheap chuck. There is no indication on the box as to whether it is of Indian or Chinese origin.

There have beed adverse comments on the quality of current Jacobs branded chucks on the forums in the USA, also.

Edited By old mart on 24/02/2023 15:44:01

I have used keysteel for making toolholders, en19t or en24t would also work well. The only disadvantage of using mild steel is that the insert pockets will be softer and more prone to damage than harder grades of steel. If you normally shim for height, or there is room, then the custom tool shanks can be made deeper which makes them stiffer. All the tools used in the museum's Smart & Brown sit at 17.53mm height and are milled down from 20mm shank tools which reduces greatly the need for shimming as all 3 toolposts are matching heights.

Edited By old mart on 24/02/2023 15:29:20

Edited By old mart on 24/02/2023 15:31:50

As Martin Kyte says, it is the diameter of the shanks, not the threads which define whether the endmills are imperial or metric. It is vital that the shanks fit the bores of the collets exactly, and a 5/8" will screw into a 16mm collet and not perform properly, so beware. There are several different types of collet, ranging from the Clarkson, the Osborn (now available as posilock) and Acramil. And the makers have changed the designs over the years, to boot. The metric posilock types which I use in the Osborn Titanic II have a band turned in the flange to denote them, the imperial ones do not, and Clarkson do that with their collets,too.

If you can read the sizes on the cutter shanks, they will be either metric decimal or imperial fractions, otherwise measuring is required.

Any lathe is a real lathe, no matter what size it is. I have a little 7 x 12 Chinese lathe in my garage, not used much as the Smart & Brown model A at the museum is much nicer to use. There are many improvements that can be made to cheap lathes which make them smoother and more accurate. Myfords are the right size for most model makers and will give many years of pleasure, they are not industrial production machines, that is not what they were designed for. There are people making superb models with very limited facilities and there are those who have all the gear and no idea, you know what I mean.

I went into Halfords ten years ago and asked for a tin of valve grinding paste, to my astonishment, they had never heard of it. I went to a small car bits shop and the guy said that there was a choice of two different makes in stock. I would choose the finer grade in the double ended tin. I would avoid diamond  abrasive for valves.

Edited By old mart on 20/02/2023 21:09:39

If you make a saddle stop, the tool tip can be set within a gnats c--k of the jaws safely, and if using power feed that close, then cut away from the chuck.

I have both edge and Firefox on my pc's, but only use the latter. Keeping edge unused is no problem, and might be a good thing if Firefox has difficulties.

Assuming that the jaws are closed, the zero can be reset without removing the glass pointer. The pointer spindle is spring loaded against the rack and with a suitable fine probe, you can get it to jump some teeth much closer to vertical. They used to include the little tool with new calipers.

Here are the official Royal Mail requirements for sending batteries.

**LINK**

Edited By old mart on 20/02/2023 19:02:04