Member postings for Mike Crossfield

Aside from having superior grip, a decent collet chuck will have much lower run out than your average 3 jaw SC chuck. With a 3 jaw you will most likely be cutting on a single tooth.

Tractol enamel is superb for machinery. Tough as old boots. High pigment content and slow drying, so you can get a good finish using brush application. Spaying even better. Available in a huge range of colours. Ferguson grey is a good match for Myford grey. Smith and Allen is a very helpful UK stockist.

I bought a Delta 2 speed scroll saw some years back, thinking it would be useful for metalwork such as crossing out brass clock wheels. It has not been a success. Even on the slower of the two speeds it is too fast for metal cutting, despite much experimentation with different blades. Blades don’t last very long, and break very frequently (with heart -stopping shock to the user!). It’s very good for cutting thin plywood, but I’m back to the piercing saw for metal.

Thanks Maurice

I suspect that the factory used some some kind of piloted reamer. I will have to give this some more thought.

Maurice

Hope you’re back in good health.

Thank you for your detailed reply, which is very helpful.

However, I was particularly interested in how you reamed the bushes in line. Did you use a piloted reamer?

I also picked up on your comment about a fibre washer on the LHS of the swing head. I have always wondered about the sideways play of the swing head on my lathe, so I’m now wondering if there should be a packing washer(s) here to take up the play.

Regards

Mike

Dennis

In case it’s of interest, and to give you some reference points. I was doing some turning for an hour or so on my S7 this afternoon, mainly around 600 rpm. For my own interest, when I’d finished I ran the lathe up 1500rpm for a couple of minutes, and then to its maximum speed (2150rpm) and let it run for 7 or 8 minutes to see what bearing temperatures I would get. Temperature on the left hand countershaft bearing housing was 30C. Temperature on the rhs was 25C. Headstock bearing housing was 31C. For reference the ambient workshop temperature was 17C. My lathe dates from 1958, and as far as I know it still has the original countershaft and oilite countershaft bearings. There is some play here, certainly rather more than you reported in your lathe, and I do need to top up the oil cups at the start of every session (with ISO32 hydraulic oil). However there is no evidence of oil bubbling out of the oil cups.

Question for Maurice:

When you reamed your new bushes how did you ensure the two bushes were in line? did you have some kind of pilot on the end of the reamer which spanned the two bushes?

I'm planning this job myself in the not too distant, and I've been puzzling over this.

TIA

Mike

Hopper

Dennis’s machine is a Super 7, but your last 2 messages appear to relate to an ML7.

According to the Myford website, the Super 7 countershaft bushes are 7/8 I.d. and 1 1/8 o.d. The lengths are not specified.

Mike

I’ve been very pleased with the Swiss pattern Tome Feteira needle files sold by Arc Euro Trade. Cheaper than Vallorbe, and good quality.

Mike

I have an MES Quorn kit, castings etc, which I bought 10+ years ago from someone who had made a start, but then put the project aside. Not much work done. Shortly after I bought it I picked up an Alexander 2CG in an auction, so it’s been in a box under the bench ever since. If anyone is interested send me a PM.

Mike

Ndiy

I used a clock rate in the control unit such that the feed advance takes just a fraction of second. Since the trigger occurs just before the reverse of the feed stroke there is little risk in normal operation of the advance occurring during cutting.

A backstop buffer would be no bad thing, but If you are able to find a microswitch like the one I used you will find that the flexibility of the operating wire is such that it will absorb considerable overswing of the handle without any damage(so far!). Not clear in the photos, but I mounted my microswitch with a single screw, so I can easily tilt it to make some adjustment if I want to vary the length of the stroke.

I seem to remember adding an RC combination on the microswitch input to prevent double triggering.

Regards

Mike

Chris

The stepper motor is a Nema23 5v 1A unit that I had in the spares box. It’s just about man enough for the job, though if your slide is stiff you might want to go up to a beefier version - you can get higher current Nema23 motors in longer lengths with correspondingly increased torque. The controller is my own design, using a couple of digital cmos chips and a few discretes. Quite simple, just responds to triggers from the micro switch to give a selectable number of pulses to the stepper motor driver. The direct gearing worked out quite nicely with a 400 step/rev stepper motor, so it was easy to arrange for step sizes of 2, 4, 8 or 16 thou. Regretably I don’t seem to have kept details of the circuit, The stepper driver is a standard design based on discrete components which I had to hand.. If I was doing it again I would use one of the widely advertised eBay Chinese drivers which are more efficient and cost just a few pounds. It’s a good idea to allow for disconnection of the stepper motor when you want to use manual feed. If you don’t disconnect the motor from the driver there is significant “cogging” when you turn the handle, even with the power off, due to back emf in the motor. The effect is much less with the motor disconnected.

Regards

Mike

GOk, here are a couple of photos of my Adept 2 with stepper motor feed. The micro switch which triggers the feed can be seen behind the control box. There are another couple of photos in my album.

Regards

Mike

The micro switch arrangement was a quick lash up to test everything out, but it worked so well that it became permanent and has been in place for 5 years now. It’s one of those micro switches with an actuator which is a length of springy wire. The operating lever for the shaper simply butts up against it on the back stroke, and the spring absorbs any overtravel

I’ll try to take some photos tomorrow.

Mike

Chris

If it’s of any interest I modified my Adept 2 by adding a stepper motor on an extension to the feed shaft. Some simple digital electronics gives a range of feed increments, triggered by a micro switch positioned so that it’s actuated by the operating handle.

Mike

Correction. I meant 1 pulse/minute of course.

Simon

A few years back I converted a very similar clock for an acquaintance. I seem to remember that the solenoid needed 24 volt pulses. I build a driver based on a watch crystal, divided down to give 1 pulse/sec. If I was doing it again I would simply divide 50 Hz mains. Be aware that these mechanisms are quite noisey. OK in the workshop, but the clunk every minute might be irritating in a quiet domestic situation.

Very nice job Brian.

Unfortunately I don’t have access to cnc, so I’m probably going down the etching route. Since I need a large dial the cost of brass sheet is non-trivial, and I have been wondering whether it would be feasible to use copper clad circuit board. The copper layer on circuit board is quite thin, about 1.8 thou on the common 1oz board or double on the less common 2 oz board, so my main concern is whether there would be enough depth for wax filling. I probably need to do some tests.

Found it!

It’s in a 2013 post entitled “John Wilding Regulator” by Russell Eberhardt. The details of etching the dial are on the 3rd page of the thread.

I think it all comes down to condition. If the existing ML7 tailstock is in good order, with minimal barrel lift when applying the lock, minimal slop in the handwheel, and a good height match to the headstock spindle, stick with it. A secondhand Super 7 tailstock is an unknown quantity, and you could end up paying a high price for a worn out item.