Member postings for Andrew Moyes 1

The Stuart no2 pump was the very first thing I machined on my brand new Myford back in the 1970s. I chose it because it looked easy, then struggled with the impeller.

The casting was held in the 4 jaw with the flat back facing the tailstock. It was faced off then the blind hole in the centre was drilled and tapped. The remaining machining was done with it mounted on its shaft which was held in the 3 jaw chuck. So far so good.

My problem was that I couldn't set the top slide over to the very shallow angle needed to machine the front of the impeller. The ML7 won't go beyond 45 degrees. There are various fixes for this which have been covered since then on this forum but having to make extra tooling can be quite off putting to a beginner. I solved it by mounting the vertical slide on the cross slide. The tool was held in a vice bolted to the vertical slide with the tool pointing towards the headstock on the centre line of the lathe but moving vertically up and down. The vertical slide could then be tilted a few degrees from the vertical to achieve the shallow taper. No extra tooling needed.

If yours is a Super 7 or some other make with a different top slide design, you may not have the same problem.

Andrew

My old Myford catalogues say 'Collets are available in 64th increments in sizes 1/16" to 1/2" and from 2 to 13 mm in 1/2mm increments." So I don't think a collet as small as 3/64ths was made and would explain why you can't find one. I hope this helps!

Andrew M

Quite.

A

I recently tried an Eclipse magnetic chuck for light milling on a Dore Westbury. It wasn't a success and I won't do it again. The chuck and end mill became magnetised and it all became a swirling mess of swarf. That doesn't happen with a (non-ferrous) grinding wheel of course.

Andrew M

Edited By Andrew Moyes 1 on 31/03/2019 19:43:10

I recently bought a secondhand Myford ML8 woodwork bandsaw attachment with the intention of using it for metalwork. They occasionally come up on ebay for about £80 - £100. I have secondhand ML8 lathe (there are plenty of those on ebay) and have shortened the tubular bed to make the bandsaw into a dedicated machine. Having said that, the unused side of the headstock might be fitted with a faceplate and table, and used as a disc sander.

The Myford bandsaw is very solidly made and I hope it will be good for metalwork. It's quite small by woodwork standards but big enough for my metalwork. The plan is to use the pulleys in the headstock to slow down the blade speed and if necessary a variable speed drive on the motor.

Andrew

John - if you join Yahoo Groups and join the group for dwmill, you'll find the drawings in the files section.

Andrew M

The gear train cover on my big bore machine has a cast-in counterbore around the hole for the spindle to ensure the swarf doesn't fall onto the gears. The flanged collar on the left hand end of the spindle, supplied with the lathe, makes sure the swarf falls clear. Is yours not the same? I can't tell from your photos. Here's mine...

Andrew

I have a pair of needle thrust bearings which I intend to install on the cross slide feedscrew of my Myford, as described George Thomas’s book ‘The Model Engineers Workshop Manual’. I now realise I don’t understand how these bearings work. In a taper roller bearing, the inner end of the roller is smaller than the outer to allow for the smaller circumference per revolution. In the needle thrust bearing, the rollers are parallel. Won’t that mean that the rollers are in a state of sliding or scrubbing rather than rolling? How do they work without friction? Am I missing something?

Andrew

My lathe is the same. The strange thing is that if I top up the oil cups and run the lathe in forwards, one bearing immediately sucks up the oil and the other throws it out of the oil cup. If I top up the cups again and run in reverse, the first bearing throws it out and the second sucks it up. Very odd. Anyway, as these are self oiling bushes, they should run for years without needing replenishment. I now do it once every six months or so and don't worry about it.

Andrew M

Regarding finishing sintered bearings to size, this might be of interest. I recall reading many years ago in a bearing manufacturer’s literature that the recommended method was to press through a precision ground steel ball. This was to avoid smearing the surface with a reamer which would destroy the sintered properties, as noted by others.

I recently replaced the Oilite bearings on the pulley of my Tom Senior mill. There are two adjacent bushes, one being flanged and the other plain. Although I bought both from the same supplier, the bushes seemed to be by different manufacturers. The colour of bronze was different and one had a wall thickness a thou or so larger than the other, resulting in a stepped bearing. I decided to try the ball sizing method and obtained a 1.1/8” steel ball. At first it virtually dropped through the bearing due to the working clearance. A quick calculation using the coefficient of thermal expansion of steel suggested that warming the ball to 100 degrees might be enough to provide the necessary increase in size. I boiled up the ball in water in a saucepan for 15 minutes then pressed it through using a drill press. A rod was mounted in the drill chuck after drilling the end with a large centre drill to form a conical seat. It has resulted in a very smooth but open surface.

Edited By Andrew Moyes 1 on 16/07/2018 09:29:55

I was sufficiently impressed at the Doncaster show to buy one. I've enjoyed using it since then with excellent results. Yes, it is a little expensive but is well made, and you are paying for some good ideas and the tool's development. It has opened up a whole new aspect of lathework and is worth it for that reason alone. Working a tool directly by hand rather than twiddling knobs is a refreshing change and is perhaps more akin to wood turning.

I soon found the importance of locking all slides. You are pushing the tool forwards against a pin and any backlash in the feedscrews can spoil the work. I made up some special extended Allen keys to suit the locking screws on my Super 7. I also turned up a vertical pin to fit in the holes in the bedplate. That enables the tool to be aligned with the centreline of the lathe when ball turning and allows the tool to be set to the radius of the ball. That should be part of the standard kit but is easily made.

It would have been better if there had been a live demonstration at the show rather than relying on a video but hopefully that might be possible at future shows.

Andrew M

I’m pretty certain I saw the lathe beds at the Myford factory being gang-milled at one setting so the four shears should be perfectly parallel. They ground the top of the bed but not the shears. The finish on the shears is relatively rough. The result on my lathes (ML7 and the Super 7 that replaced it) is that the shears bedded in relatively quickly (I mean over a few years) and the saddle becomes loose on the left and tight on the right, while the tailstock becomes loose on the right and tight on the left. At some point, I’ll bring the shears into line with a slip stone but am leaving that as long as possible.

Andrew M

Apologies for joining this thread late but the following may be of interest.

When I first got my ML7 lathe in 1971, I renewed the white metal bearings and carefully scraped them to fit. The measured spindle clearance was 0.0005” using a DTI and long bar in the chuck. After 40 years’ use, the last 10 with a VFD-controlled 2,850 rpm motor and top speed of 1300 rpm, there was no measurable change in clearance.

When I first fitted the 2850 rpm motor, I ran the lathe at top speed for 1.1/2 hours to check for overheating. The bearing caps were moderately warm to the touch but nothing untoward for such a close-fitting bearing. Myford themselves were not concerned as they offered a two speed 1450/2850 rpm motor until the lathe went out of production. It could be fitted to any ML7 but was mainly aimed at Trileva fitted lathes to give instant access to six speeds instead of three. The Trileva used standard white metal bearings.

The idea that Myford introduced replacement phosphor bronze bearings because of overheating white metal bearings is definitely a myth which has unfortunately found its way onto Tony Griffiths’ excellent site and is becoming 'gospel'. I remember the Myford press release at the time which said it was due to the prohibitive cost of obtaining white metal bearings. Phosphor bronze was a cheaper alternative but it meant replacing the spindle with a hardened version as the unhardened one previously used was not compatible with bronze.

If you are buying a new three-phase motor and VFD, I don’t see the point in running a 1450 rpm motor at 100 Hz when a 2850 rpm motor can be run at 50 Hz within its manufacturer’s rating.

Assuming your bearings are correctly fitted and lubricated, and not tight, installing a 2850 rpm motor with a VFD is for me a ‘no brainer’. I certainly wouldn’t swap the lathe because of fears about the bearings.