Unusual Thread

[Tom GullanParticipant @tomgullan59234]

Hello,

I have been asked by a friend if I could cut a thread on my Myford Super 7. The diameter is 24.7 x 1.693 pitch. This job is for a nut for a collet on a Schaublin lathe.

If this is not possible, I would appreciate any information on how to go about this task.

My Super 7 is imperial but I do have a full set of metric gears.

Regards

Tom

[Tom GullanParticipant @tomgullan59234]

[JohnFParticipant @johnf59703]

I would check your measurements looks more like 5/8 x 43 tpi ? How did you measure it ?  It also could be 25 x 1,7 its not very likely to be obscure dimensions.

Edited By JohnF on 04/01/2017 22:28:46

[Roderick JenkinsParticipant @roderickjenkins93242]

Tom,

1.693mm pitch looks to be 15 tpi. Not a thread much used and not in the Myford thread tables but we should be able to find a combination of gears to get you close enough.

HTH,

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Have a look here, Tom **LINK**

http://www.practicalmachinist.com/vb/schaublin-cazeneuve-weiler-graziano-mori-seiki-lathes/beauty-schaublin-w20-collets-321515/

… It seems to confirm my suspicion that the thread is actually 15 tpi

… see post #7

MichaelG.

.

P.S. … I presume you are aware that it's a buttress thread-form

Edited By Michael Gilligan on 04/01/2017 22:49:01

[Tom GullanParticipant @tomgullan59234]

John,

The sizes come from the collet Chuck manual page 11

**LINK**

Regards

Tom

[Mark CParticipant @markc]

Rod, Michael, I did the check as well (having just finished watching the news) and got to 15 tpi as well (25.4/15=1.6933) which makes sense from a design point of view – we do like round numbers!

Mark

[Tom GullanParticipant @tomgullan59234]

Gentlemen,

Thank you very much for your quick response to my question. Is it possible to cut this thread on my Super 7?

Regards

Tom

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mark C on 04/01/2017 22:53:37:

Rod, Michael, I did the check as well (having just finished watching the news) and got to 15 tpi as well (25.4/15=1.6933) which makes sense from a design point of view – we do like round numbers!

Mark

.

… and on the W20 collets [which I have] the pitch is 1.666mm

Nice; introducing thirds into a 'metric' system

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

Change the 24 tooth driver to a 32 and select 20 tpi on the box.

 

Which works out to 15 tpi or 1.69 mm

Edited By John Stevenson on 04/01/2017 23:40:42

[Roderick JenkinsParticipant @roderickjenkins93242]

If you don't have a Norton box, there are loads of options. A couple of likely looking ones:

Drivers 20 21 60 Driven 30 35 45

or

Drivers 20 40 63 Driven 35 45 60

Rod

[John Stevenson 1Participant @johnstevenson1]

Or with no gearbox and just two gears, 40 driving 75 are two standard gears.

 

We don't need no skeenking compounds.

 

Rod, You realise we have beaten all the armchair warriors working to microns ?

 

 

Edited By John Stevenson on 05/01/2017 00:11:03

[Roderick JenkinsParticipant @roderickjenkins93242]

I won't have any idlers in my workshop, every gear has to work.

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Stevenson on 05/01/2017 00:08:00:

….Rod, You realise we have beaten all the armchair warriors

.

John,

Are we to understand that you dictated that ^^^ from your Treadmill [which powers the LED lighting that supercedes the 'midnight oil'] whilst using the Welder in one hand & the Angle Grinder in t'other

MichaelG.

[Neil WyattModerator @neilwyatt]

Posted by Roderick Jenkins on 05/01/2017 00:37:19:

I won't have any idlers in my workshop, every gear has to work.

Rod

Get your coat!

Neil

[JohnFParticipant @johnf59703]

Posted by JohnF on 04/01/2017 22:26:39:

I would check your measurements looks more like 5/8 x 43 tpi ? How did you measure it ? It also could be 25 x 1,7 its not very likely to be obscure dimensions.

Edited By JohnF on 04/01/2017 22:28:46

Oh dear don't know where those numbers came from !!!! past my bedtime so apologies !!!!

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