Member postings for old mart

I once had a car which had its prop shaft made from mismatched halves. The splines could not be aligned exactly to make the yokes parallel, it was 1/2 a spline out. I didn't notice the error until I replaced the UJ's.

I normally lock the tailstock and its barrel, retract the jaws of the chuck below the nose and give the chuck a rap with a soft mallet, or a copper mallet if large size drilling is to be carried out. Don't hit too hard, especially with a self extracting system.

The MT2 tailstock barrel of the museums' lathe had a poor taper, and I managed to get a new one intended for another model. The important dimensions were the same but instead of a slot for a tapered drift extractor, it was designed for self extraction. We soon milled a new extraction slot in the barrel. I don't trust self extraction with a very tight Morse taper.

 I have a little 7X 12 mini lathe at home, it came with a 1/2" chuck, far too large, it now has a 3/8", 10mm one which is more in keeping with a small machine. I once tried drilling a 1/2" hole in steel, and it tended to stall and blow the fuses.

Edited By old mart on 30/09/2019 21:27:18

Thanks to that diagram, I now know what the difference is.

I would go for a treadle operated mechanism, if it's from Australia, it looks like it has spent the last hundred years at the bottom of a billabong.

Threaded shank Clarkson tooling is not guaranteed foolproof. They can snap at the point where the thread meets the shank, it has never happened to me, but I know toolmakers and millers who know better.

From studying the photographs, the colours of the op's wires are the same as the motor plate diagram. This would make it easy to get everything connected correctly.

RED-BROWN

YELLOW-WHITE

BLUE-BLACK

The 3 input wires can be connected any way round, only swapping any two if the motor rotates the wrong way.

What you have got is three phases going into your motor which connect together at the neutral terminal. To change to delta, you have to disconnect the three neutral wires and move them to the appropriate phase connections. The neutral terminal will now have no wires going to it. You need a meter with a low ohms range to find out which wire goes where. My poor diagram shows what it should look like Good luck. Check the connections when the wires are disconnected from the neutral.

Edited By old mart on 28/09/2019 22:38:02

Dead right, SOD, I have an ER25 plate which fits straight on the lathe, its never been used, I'm not afraid to use a four jaw chuck.

I have now got an ex16 x 8 unified insert which will go in a left hand internal holder to thread away from the chuck when I do the backplate. The chances of the threads being Whitworth are pretty much zero, it being from the USA as mentioned. The standard UNF, formerly NF 1 1/2" has 12 tpi, so it must be a special. I think the lathe is a 12 X --.

You need "delta" connections, but the motor is wired "star". I don't know if the wiring can be re arranged, hopefully someone will know. If you bought a new motor it would be easy to change from one to the other, but the mountings and shaft diameter might have changed.

ER40 collets go to 30mm and can be bought with square of hexagon bodies to go in lathe chucks. The square in an independent four jaw chuck would be the best bet, as you can get them running properly. There are also MT3 holders with a drawbar thread or tang.

This one has the drawbar thread:**LINK**

Using the original length spanner will usually give a lower tightness than recommended. I use er25 which only goes to 16mm, and I milled a spanner flat on the holder. The cutters are mounted before fitting the R8 into the spindle, and the spanners get leaned on on the top of a workbench, also used for undoing the collet. We all use this method, and have never had a slippage. One day I will make extensions for the spanners, I recon they need to be 12" long.

I bought both the motor and the VFD from the Inverter Drive Supermarket, and studied their "quick start" pdf's before buying. This was to ensure easy wiring, and remote buttons and speed control potentiometer. Be advised, their prices are ex vat.

 Some of the vfd's that they sell do have the option of a fully equipped remote switch box.

Edited By old mart on 27/09/2019 20:36:24

I was amazed to see that a motor manufactured in the USA some time ago would have a temperature in centigrade on it, even now they are the last bastion of Fahrenheit.

Its a shame, I just looked for M12 X 1 nuts on that unmentionable site and had a choice of half nuts, full nuts and stainless steel ones.

I

Edited By old mart on 27/09/2019 16:33:34

Right you are, ndiy, my maths was not up to scratch yesterday.

Just as well, I don't want more than 3500 rpm in top gear, the drill mill we use normally only does 2100 rpm.

Edited By old mart on 27/09/2019 16:26:22

To possibly clear up the argument about camera lens mount threads, have a look at the SRB Photographic web site, they manufacture pretty much every adaptor there is:

**LINK**

You could easily get away with a light press fit for the plugs and Loctite when they are assembled. Use steel plugs with a visible turned finish, and they will bond in the drilled holes beautifully. Use 638 for fast curing, or 620 for a slow cure, they are both very strong and will not worry about oil or the temperatures in an engine.

 After 24 hours, flush through with brake cleaner, or carburettor cleaner, to wash out any surplice uncured Loctite.

Edited By old mart on 26/09/2019 21:29:23

Edited By old mart on 26/09/2019 21:31:03

If you already have three phase, it will be 415V and the motor will be wired in star. If you don't have three phase and want to run a three phase motor from domestic 230V, then a suitable VFD which has 230V output in three phases will require your motor to be set to delta. The advantage of a VFD is that you can adjust the motor speed.

I am in the last stages of doing exactly that. I have a six pole motor which runs at 935 rpm @ 50 Hz and the inverter will be set to run the motor between 25 Hz and 75 Hz, which is from 467 rpm to 1870 rpm. This gives the mill which only has four speeds by belt, a much improved range of speeds. The motor could be run at lower speeds, but the power drops off quickly, as even at 25 Hz half of the power is lost.

Edited By old mart on 26/09/2019 21:12:38