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Member postings for old mart

Here is a list of all the postings old mart has made in our forums. Click on a thread name to jump to the thread.

Thread: Smart & Brown Questions
27/10/2021 17:08:13

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.

Thread: Invertek Optidrive Control Issue
25/10/2021 21:00:23

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.

Thread: Old 1/2" chuck
23/10/2021 19:14:51

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.

22/10/2021 18:27:49

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.

Thread: Inserts
18/10/2021 20:18:05

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

My 1.5mm inserts are 0.059" wide.

18/10/2021 18:33:30

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

Thread: big jaws for my milling vise
18/10/2021 18:27:49

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.

Thread: KLG Mystery Object.
18/10/2021 18:21:09

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.

Thread: Hi all, newbie with first lathe, rare one i think.
18/10/2021 12:53:28

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.

17/10/2021 21:22:59

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.

17/10/2021 18:58:33

Welcome to the forum, Wayne, it certainly is an interesting machine. I would personally choose a 1 hp motor, 0.75Kw and a VFD since its quite old and needs a gentle touch. And keep the maximum rpm below 1400.

Thread: Old 1/2" chuck
17/10/2021 18:48:03

Thanks, Jason, that thread is very interesting. As for the taper of the arbor, With the chuck dismantled, I could get a reasonable measurement of the end of the arbor and compare it with the outer end. Having some very heavy metal blocks and a suitable thick walled tube, it was easy to break the taper with a large punch and a club hammer. I have measured the taper and it is close to J33,

J33 0.624" x 0.5604" x 1" length.

Arbor 0.624" x 0.581" x 0.903 length.

Edited By old mart on 17/10/2021 18:48:53

Thread: Seal selection
16/10/2021 21:46:29

If you run the mag at 3000 rpm it will outlast the motor.

Thread: Old 1/2" chuck
16/10/2021 21:34:58

I have a 100mm 4 jaw independent chuck in a cupboard at the museum, marked Crown, and foreign. You reminded me that this 1/2" chuck has foreign marked next to the MT arbor. The screws are 8-32, replacing the original slotted ones which had seen better days, I had expected 4mm, or 3BA, but the 32 tpi gauge was the best fit and they screw in nicely. The design would work with hexagonal bar stock, but 1/2AF would be too big on the corners.

Edited By old mart on 16/10/2021 21:37:30

Thread: Load reactors for VFDs
16/10/2021 20:48:03

VFD's can be programmed to give a very slow gentle start and also slow stop, wouldnt this be adequate to run your old motor?

Thread: Old 1/2" chuck
16/10/2021 20:38:52

_igp2835.jpg_igp2830.jpg_igp2829.jpg_igp2827.jpgOne of the unusual items left to the museum with other tools is this little 1/2" two jaw chuck. It was on a MT1 arbor which I removed to find out which Jacobs taper it had. It looks like it is intended to hold round stock up to 1/2". I took it to bits and cleaned it up a bit to find out whether it is worth getting a J33 x MT2 arbor for it. I fitted it onto a 12mm ground steel bar running 0.0005" tir and it runs about 0.004" tir on the body (the original MT1 arbor may be bent). I initially thought it was for holding taps, but the jaws make more of a hexagon shape.

I have some pictures, but have forgotton to add them to my album before posting this thread.



Edited By old mart on 16/10/2021 20:42:06

Thread: Seal selection
15/10/2021 18:26:55

Motorcycle wheels commonly rely on just the seals built into the bearings, even trials and scrambles machines, so you may be worrying too much.

Thread: Restoration and modifications to a Tom Senior light vertical mill
15/10/2021 18:13:00

The type of indexable cutter I mentioned is not designed to plunge cut more than about 0.01", 0.25mm because it cannot cut in its centre. With that limitation, you could run sideways after the start and cut a groove in several depth steps, or you could use a smaller centre cutting mill to produce a narrower groove before using the bigger one. These indexable mills are available from 10mm diameter with one insert right up to 100mm diameter with about 8 inserts. The shell mills which fit on an arbor to suit your spindle start from about 40mm 4 insert, below that they are usually solid shank. I have a 25mm one with the shank turned down to 20mm to fit an R8 collet.

The indexable type are cheaper and the Chinese inserts for steel or aluminium are very cheap, and they are double ended so a box of 10 has 20 cutting edges.

Edited By old mart on 15/10/2021 18:16:08

14/10/2021 20:09:55

That is a lot to pay for one cutter. I wonder if you could get by with a 1" diameter indexable cutter. The type I had in mind uses APHT 11 or 16 inserts.

This is what I mean. In the USA or Canada, similar products would be more likely to be in inches rather than metric.

Edited By old mart on 14/10/2021 20:14:04

Thread: Plastic Chuck
13/10/2021 19:31:56

Welcome, bjk, I personally think that you would be better off avoiding a plastic chuck, there will be plenty of common old cast iron ones available foro the suppliers advertising on this forum, not to mention ebay.

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