Member postings for old mart

Are you suggesting that it would be in order to "push or pull it by hand" when taking a cut? I would call that an extremely foolish suggestion to make when a novice might actually try that not knowing any better.

Edited By old mart on 30/10/2021 21:54:34

I beg to differ, Howard, the cylindrical turning is all done with the compound, that "saddle" is fixed in place while turning with the large hand tightened screw visible under the bed.

Also could be used for holding drills if you freehand sharpen them.

From the photo's I would guess that you have been unlucky to get a boring bar with a round shank. If that is so, then the normal angle of the insert should be tilted down about 7 degrees, with the tip at or slightly above the spindle centre line, (+0.010" /+ 0.25mm would be fine for that size of bar). Most of the bars on the market have flats which preset the angle of dip for the insert.

The only drawback that would put me off is the absence of a saddle.

It looks to me that the nut has been worn down or modified sometime ago. I would look closely at the marks on the side to see if any sign of a thread is present. There is a chance that it has a left hand thread.

The Clarkson, Acramil, Osborn Titanic and similar will only work with threaded shank cutters. Solid carbide endmills or any plain shank types plus the threaded shank cutters will work in the er type system. It is easy to extend the er spanners, I made 12" long ones for the er25, so the tightness need not be a problem.

The pulley on the right looks to me marginal if the hole is to be bored to the size of the left one. Measure the diameter of the bottom of the smallest pully wheel to see if it is bigger than the proposed bore. I would not be happy with less than 2mm, 0.080" wall thickness after boring.

I bought some German made spray oil on ebay and tried it on the extremely stiff leadscrew and nut for the drill mill X axis. It was unbelievably good after having removed the bed several times without being able to sort out the problem.

I can recommend this:

WURTH HHS 2000 highly adhesive synthetic lubricating oil.

Here are the wiring diagrams, I hope you can make them out.

Welcome, John, there are a few of us using S & B model A lathes, I use the Mk 1.5 at the Helicopter Museum at Weston Super Mare. There are very few spares available, but Lathes UK do a useful set of manuals and parts lists. I always keep an eye out for listings on ebay, but most of the sellers want an arm and a leg for old parts. I gave up on getting changewheels and have made new ones out of metric mod 1 blanks which are similar in size to the originals.

If I remember, I will take a photo of the wiring schematic and post it on the forum for you.

I wired up two latching emergency stop buttons in series with the remote control standard stop button. The advantage is that being latching, they have to be reset manually after use. Until then the start button will not work. The readout on the vfd reads "nst" until both emergency stop buttons are reset and "rdy" when the normal start button is usable.

If the B16 arbor does not work, I will put it aside as a spare like the JT33 one. I may well simply Use the jaws to clamp onto a true running 1/2" steel bar as in the first post and bore the taper parallel to shrink in a MT2 soft ended arbor. This is purely an exercise, as I cannot really think that it can match a standard drill chuck. Trying to measure these type of angles which run to seconds of arc with a digital angle finder which only resolves 6 minutes is futile.

Looking at the series of Morse tapers, I find it difficult to understand the mindset of the person who failed to make them all the same angle.

An update on fitting a MT2 arbor with a JT33 end. I bought one from Myford LTD, a good price and fast delivery. It was a failure. I had runout of about 0.020" tir. After removing the arbor, there were witness marks at the large end of the taper and I could feel the mismatch. That meant that JT33 had too steep an angle. After some investigation, the only candidate left would be the B16 which is based on the MT2 angle, and has a large end of 0.6195"

The JT33 angle per side is 1.80422 degrees.

The B16 angle per side is 1.43055 degrees.

Pipped at the post by Tony, Sandvik do GC1125 for stainless steel.

My 1.5mm inserts are 0.059" wide.

Very narrow for parting, unless for special purposes, it will be very difficult to identify them as so many are proprietry, as far as I know parting inserts only go down to 1.5mm. I have some Kennametal grooving inserts which go very narrow, but only at the tips, the main body is much thicker, their maximum depth is limited.

Edited By old mart on 18/10/2021 18:38:28

Not Spanish, Portugese, Celso comes from Brazil. The jaws would be good for holding soft materials, or very thin plate, but would not grip as tightly at the top.

I bought a box of ten turning inserts very cheaply on ebay and made a holder for them. They look like square white tablets, about 10mm per side and 4mm thick, much lighter than carbide. The edges are blunt, but they certainly have no trouble turning fully hardened HSS but you have to keep clear of the red hot sparks.

We all look forward to regular updates on progress with your lathe. Have you measured the spindle threads and fitting? You will probably have to make custom backplates from blanks or solid cast iron for any additional chucks needed.

If the motor looks good, go for it, you don't have to run it at its limits. A decent modern oil of practically any type will be superior to the stuff they had 80 years ago, I would use synthetic motor oil myself.