Granville lathe gib-strip adjustment grub screw sizes

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Granville lathe gib-strip adjustment grub screw sizes

This topic has 8 replies, 6 voices, and was last updated 1 April 2022 at 16:31 by Howard Lewis.

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30 March 2022 at 23:47 #592131
David Anson
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@davidanson80646
Colleagues,

With some trepidation I make my first post, and from metric New Zealand at that.

I recently purchased a Granville CSL2 lathe which I believe can be correctly described being of the Grayson family with many Myford kin. I'm a complete novice with engineering lathes but I'm embarking on a little 'tidying up' before venturing forth.

I'd like to replace the heavily worn slotted gib-strip adjustment grub screws and with a hex type hopefully. I noted lengthy discussion in this forum under https://www.model-engineer.co.uk/forums/postings.asp?th=99448&p=2 circa 2014 in relation to the grub screws for that lathe. I sensed that the consensus was the grub screws for that unit were most likely 2BA vs 3/16" BSF.

I think its a longshot but to assist my purchase, most likely out of the UK, might anyone know the specs for the Granville/Grayson? If it helps in anyway I've gauged it as best I can and it appears to be close to 3/16" 30tpi.

Cheers David
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30 March 2022 at 23:47 #14518
David Anson
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@davidanson80646
31 March 2022 at 08:01 #592151
Thor 🇳🇴
Participant
@thor
Hi David,

Welcome to the forum. I assume you have checked lathes.co.uk?

Thor
31 March 2022 at 08:27 #592154
David Anson
Participant
@davidanson80646
Hallo Thor,

I'd researched that site fairly extensively but not posed that specific question imaging that Tony would be overwhelmed on a daily basis. Will do so if that's the recommended approach.

Thanks, David
31 March 2022 at 08:29 #592155
Hopper
Participant
@hopper
Posted by David Anson on 30/03/2022 23:47:18:

I think its a longshot but to assist my purchase, most likely out of the UK, might anyone know the specs for the Granville/Grayson? If it helps in anyway I've gauged it as best I can and it appears to be close to 3/16" 30tpi.

Cheers David

Welcome to the forum. Not a common brand of lathe so you might wait a while for specific info.

3/16 BSF is 32 TPI. 2BA is 31.4 TPI. Close but no ceegar.

And thread flank angle is 55 deg vs 60 deg. Which is probably not critical on mass produced fasteners.

You will need a 32TPI thread gauge, or a tap of any diameter with 32TPI and a good magnifying glass.

Or take a punt and buy some BA screws and see if they work. If not, buy some BSF. Or vice versa.
31 March 2022 at 23:25 #592292
Pete Rimmer
Participant
@peterimmer30576
If that was mine and all I had easy access to were metric fasteners I would definitely just run a 5mm tap down the threads and buy 5mm screws and locknuts.

Edited By Pete Rimmer on 31/03/2022 23:30:19
1 April 2022 at 09:37 #592331
Graham Flavell
Participant
@grahamflavell13482
Hi David,

If it is any help I have just removed one of the adjusting screws on my Granville Senior and it is 2BA.

Regards

Graham
1 April 2022 at 09:45 #592333
David Anson
Participant
@davidanson80646
Thanks one and all, most grateful. Tempted by the 5mm conversion but Graham's thoughtful advice is just what I hoped for.

What a forum, cheers.
1 April 2022 at 16:31 #592413
Howard Lewis
Participant
@howardlewis46836
AS Hopper says note the angle of the thread, as well as the diameter and pitch.

BSF, BSW, BSP, BSB are 55 degrees.

Unified and Metric are 60 degrees, and BA is 47.5 degrees.

Not surprised to read that the grubscrews are likely to be 2BA.

You will always find help on here.

Good luck with the restoration.

Howard
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