Hello Chris,

I am unclear about what you refer to as the clasp nut and the grub screws associated with it; if they are what I think they might be that will not help at all in correcting the slew you are getting part way down the length of the bed.

Sadly I believe you are correct in diagnosing bed wear and the short answer for an old lathe of that vintage is to learn to live with it and develop coping strategies. I think it very unlikely you will find any organisation who would be prepared to regrind the bed and angled side edges, nor would you be happy with the cost if you do find one.

Depending on your experience and expertise some might suggest you try remedial scraping of the side edges either side of centre to level out the playing field so to speak, but it is by no means an easy skill to master even on flat surfaces and then to put into practice on shapes like that. For a first job I would avoid it.

An approach I might take if the lathe was mine is to try careful lapping with fine grinding paste of the side edges with a wedge shaped wooden block, fastened to a section of flat plywood riding on the top of the bed and "working out" the high areas to either side of centre.

I know it sounds dreadful to contemplate such practice but with due care and a good straight rule to refer to, the limits of the hollowing can be spread out to form an average over the length of the bed. I do emphasize that CARE is the watchword and cleaning up very thoroughly every trace of residual abrasive material is essential to prevent further unintended wear later on.

I hope that helps you with some ideas, but such problems are to be expected on old lathes that have really done their time.

Regards Brian

That does sound like bed wear to me.

Regrinding the bed could be problematic, but you might be able to find someone with a decent sized vertical mill that would be prepared to give a lick to the worn surfaces and get you back with a usable machine again. It's what I would do.

Martin.

If the saddle is slewing you probably realise that as well as the bed each end of the saddle gets extra wear. Thus when you snug it up tight the middle is making contact but each end is probably clear. So with a short contact length it is even easier for it to twist.
I suggest before trying to work on the bed you have a look at the saddle bearing surfaces. If the gib strip is a thick block like the Drummond then that too needs checking for flatness. The smaller areas of these parts should be easier to work on but remember the cross slide reference surface has to be kept perpendicular to that for the bed.

Comments.

The Myford M Series have dovetail beds, so wear on the dovetails may be less easy to recover, than on the flat top of the bed.

So your check with a straight edge needs to include the dovetails, (The rear dovetail may be even more difficult! ) as well as the flat top of the bed.

There will be backlash between the pinion and the rack. This is the normal method of moving the saddle, manually. Which is what you would do most of the time. In any case it is quicker than winding along with the Leadscrew, which will need 8 turns to advance the Saddle by an inch

The half nuts will be engaged with the Leadscrew if you wish to set up the change gears to provide a power feed for turning, to cut screwthreads, or to advance the Saddle by a measured distance.

For what my advice is worth, I would check one thing at a time, staring with the rear dovetail; then the front dovetail, and then the flat top of the bed, correcting the wear in each feature.

But remember that you will have difficulty putting on metal, if you remove too much. So proceed VERY carefully.

My first purchases would be a tin of Micrometer blue, and a good 12 " straight edge, plus laying in a good stock of clean rag, and Swarfega, with which to clean my. hands.

SLOWLY SLOWLY CATCHEE MONKEE!

When you happy with the bed, then clamp an accurate bar in the chuck, (1/2" minimum dia Silver Steel possibly ) and check that the Headstock is aligned with the bed. Unless your lathe is a very early one with a cast in Headstock, it should be possible to correct any misalignment by slackeinng the 1/4 BSF nuts that hold the Headstock to the bed.

Once that has been done, fit centres, and with a properly centre drilled bar and starting checking the Tailstock for alignment in first the horizontal plane, and then in the vertical plane. Adjusting for Zero deflection horizontally should be fairly easy, using the 1/4 BSW adjuster on the far side of the Tailstock. Recheck after locking with the nut!

If the centres are out vertically, you may have to scrape the underside of the Tailstock to bring the centres into alignment. If the tailstock centre is low, you will need to find some means of adding shims.

Again,BE CAREFUL, not to make matters worse! You do want a Tailstock barrel that points towards the sky, or the floor.

Either way, you will need to check that when the vertical alignment is correct, that the horizontal has not been changed since first set up.

Once you have got the lathe into alignment with as little backlash as possible, you should have a useable, mand useful, machine, even if it has foibles compared to a modern machine.

Howard

My approach to these type of issues with the Drummonds that I have restored is firstly to go at it gently and get the best compromise that you can. Something you can live with is the goal ,not perfection. Once your happy with it some minor mods to allow all motions to be locked.( This may be a feature already on the ML) Locking whatever your not moving for a particular task will solve all manner of problems. New Drummond users regularly have issues with chatter , poor finish etc and the answer is usually failure to lock the carriage , cross or topslide. One other thing will improve your turning and that is to use HSS tooling. Buy a small set to get going and then learn to grind your own. You could also come and join us on the Drummond Myford FB group..

Chris,

Sparey's book is written predominantly with the Myford ML7 in mind, but that is the detail.

The principles will apply to any lathe.

Others worth considering are Ian Bradley's "The Amateur's Workshop" and Tubal Cain's "Model Engineering Handbook"

They are all filled with useful information, especially Tubal Cain's book. As you get further into the hobby, you will find The Workshop Practice series to be very useful.

The ML series machines , differ in centre height – 3.125 for the early models ( ML 1 and 2 ) and 3.5 for the later models, with the "higher" numbers denoting a greater centre distance. They all date from just before WW2 and production ceased in the mid 40s The ML7 came out in about 1947.

Like all machines of that age, wear and abuse will be apparent, not to mention what we would regard as peculiar foibles, and facilities which we now take for granted, will be absent.

Having said that, within the limitations of design, age and abuse, they are still capable of producing good work.

Like all machines, careful adjustment can bring about huge improvements in performance.

Keep at it!

Howard

You can buy guage plate in strips.

regards Martin