All I did on my S7 with QC as a quick fix was to slacken the gib screws a bit and slide a strip of 0.030” thick gauge plate between the saddle and rearmost shear, worked so well it’s been there for years and never slid out. Sold the lathe to a friend a few years ago and told him to watch out for the shim slipping out, it never has.

Fitting an appropriate shim to bear on the previously unused rear shear on the bed does'nt appreciably alter the overall postion of the saddle on the bed. It should just return the saddlle to nominaly the same position it occupied with the original guide face in an unworn state – the shim just fills the clearance that was there originally..

I used a piece of gauge plate to sort my non-PXF S7- IIRC it was 1/16" x 1/2" by the full length of the saddlle (though it has been many years since the conversion was done & I would have to check to be certain) & I Loctited it in place. The machine was subsequently retrofitted the screwcutting gearbox and I had no issues getting things to align.

HTH

Nigel B.

Peter Sansom:

Can you provide the GHT reference?

Whilst I would not be surprised to learn that GHT had taken an interest in the same matter as JAR, I don't remember him doing so in print.