Cant give a ref to ME, but google may be your friend.  You should see a link to this very organ to article reprint  1 nov 1974

The basic version is simple.

Slacken of gibs completely push saddle fully forward against front shear and see how much room there is between back shear outer and saddle vertical.

Find some piece of material of a corresponding thickness less some small amount to allow for gib adjustment, material is usually MS, but I doubt it is a hanging offence to use brass etc.

Just hoik the saddle off and clean up the back edge of saddle, checking the bearing surface is not convex (ok if plane or concave), and attach your piece of material with epoxy, superglue or whatever you wish to use , reset saddle against well oiled back shear and tighten up front saddle gibs while adhesive cures.

That’s the basics, depending on circumstances, you may want or need to mill the back shear inner saddle bearing to allow a thicker strip,  likewise the front shear saddle bearing for more clearance (better if you don’t do the latter as you can restore saddle to original if you don’t like the mod).

There are all sorts of permutations and combinations to suit your fancy if you trawl about on the net. From personal experience, I don’t recommend Turcite, it doesn’t last and eventually tears up causing jams. Steel is the real deal.

There are some good articles in MEW by Peter Barker, who used to be on the forum as Hopper, on the wide guide conversion, and on measuring bed wear. Very well written and practical.

Wide conversion MEW Nov 2019 No 287

Measuring bed wear MEW autumn special 2019 No285

Tailstock bedway rework MEW Jan 2020 No 289

Carried out the bed conversion on my 1965 super 7 exactly as described in the articles and very pleased with the result.

Dave

I did the mod on my elderely S7, the carriage started tightening up halway down the bed. Not a problem most of the time but annoying the few times I needed to move the carriage right out of the way. I would be too lazy to slacken off the gibs but always worried about overstressing the carriage.

The write up in ME was a little off putting with the work involved, then I read here of someone who simply slacked the gibs, inserted a shim and re adjusted the gibs again. I did the same and it has worked extremely well ever since. I was a bit worried about the half nuts losing alignment with the lead screw but it has not been an issue.

You do have to be mindful of a possible effect on the relationship of clasp nut and lead screw. Rather depends on machine, amount of wear on gib etc etc. Being a myford, there is usually quite a lot of ‘slack’ available for small adjustments so that particular problem can be a bit overstated.

The trick is to get away with the least ‘reasonable’ thickness of shim sufficient to move the small inner saddle bearing off the back of the front shear, for the whole length of the bed.

I would proceed by checking current condition by moving saddle to middle of bed engaging nut and giving a turn or two on the leadscrew, then get some sort of pointy thing, referenced to the front shear and check if there is much difference between lateral measurement of pointer to leadscrew at headstock end and again where the saddle is. If no significant bowing measurable then you can:

Slack off the front saddle gib to allow 5 to 10 thou clearance at the mid saddle bearing, then measure the gap on the saddle back bearing surface. With luck you may find this is 1 to 1.5mm or there about, but total apron re-positioning will be about 10 thou.

Alternatively, measure the gap on the saddle back bearing surface which will be your shim thickness, then mill 10 to 20 thou off the mid saddle bearing surface. In this case there is practically no change to the lateral position of the apron.

In my slapdash world, neither approach would result in a significant effect on the lateral position of the apron clasp nut. However, if this not acceptable you can mill the LS bearing blocks and readjust gearing on the quadrant or ease the saddle to apron bolt mounting holes, either approach is probably higher risk than a 10 thou displacement of the clasp nut ( have you noticed what an immaculate high precision hard wearing mazak unit myford chose to use for this component!).

If initial measurements reveal there is significant lateral bowing in the lead screw to start with, you need to determine what is required by setting the saddle at a lateral position that has no bowing effect  when the leadscrew is engaged and work your measurements from there. Who knows, you may be lucky and find any leadscrew bowing is away from the lathe bed!