Myford Super 7 Narrow to wide guide conversion

Hi everyone,

Just after a bit of advice, I think its time to convert my elderly 1963 Super 7 from the narrow guide to the wide guide method.

I know there have been one or two articles detailing this, and they are very useful, the problem is that these articles detail converting the non quick change gear box models.

As i understand it there is an issue of ensuring that the leadscrew and half nuts still engage correctly when the saddle is converted to wide guide.

Since my Myford S7 does have a QC gearbox what difficulties will arise if I attempt the conversion from narrow to wide?

Has anyone done the conversion on a non powered cross feed, QC gearbox Myford S7?, and hints and tips?

All the best

Derek

I converted my S7B some considerable time ago after reading J A Radford's article in ME.

The existing construction should allow some front to back adjustment between apron and saddle if necessary; up and down via shims.

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.

An impressive bit of engineering! JAR secured his with epoxy.

Did you need to adjust the fit of the apron(the OP's point)?

Edited By ega on 08/08/2023 10:02:37

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.

I did the conversion on mine 5 years ago as part of a bed regrind. Put a piece of ground steel to fill the gap between the rear face of the bed and and the carriage as per George Thomas. Also had part of the old front guide on the the carriage milled to provide the necessary clearance.

Thanks everyone for your responses.

I thought I had most of GHT articles from the ME. I must have missed his article on the conversion. Maybe it was in his book (which I do not have). I assumed that the book by GHT was just a collation of his articles in the ME, obviously there maybe more extra info in the book than I realised.

I will take a closer look at the conversion, but once again thanks to all.

Kind regards

Derek

Dick Ganterton's thoughts on this modification (for Myford S7s) are available for download as a PDF here:

Correcting wear in lathe saddles

Regards,

IanT

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.