Warco GH1236 screw cutting 1mm pitch threads

[william shortParticipant @williamshort73832]

Hello Members

I have a Warco GH1236 Lathe but i cant find the correct information to screw cut 1mm pitch threads.

The Indicator table doesn’t show what indicator gear to use ie not 14T 15T or 16T  it shows 0T. Also the for the indicator dial engagement number it shows “/” not ie 1-8  1*3*5*7 etc.

1mm pitch is a popular size so it must be me who is not understanding.

Can anyone help me with this.

I will try and attach a picture of the table.

Thanks William

[JasonBModerator @jasonb]

Assuming it is a metric pitched leadscrew machine then you don’t need the dial if the leadscrew’s pitch is divisible by what pitch you want to cut.

So if you have a 3mm pitch lead screw you won’t need the dial to cut 1mm or any of the other pitches along the bottom row as 3 can be divided by all of them. Hence the 0T and / indication nothing.

[DC31kParticipant @dc31k]

Just to amplify on the above, not needing the dial means you can engage the half nuts at any point that they drop in freely and the thread will synchronise.

Maybe the table would be clearer if it said ‘any’ for the gear and ‘any’ for the scale (just like the ‘any’ key on your keyboard).

Martin Cleeve’s ‘Screwcutting in the lathe’ explains this very well (section 5 entitled ‘problems and analysis of repeat pick up’).

[william shortParticipant @williamshort73832]

Thank you Gentlemen.

1. My misunderstanding was I somehow thought the lead screw was 8TPI.( I think I have been reading too many American manuals for this lathe). I have measured it and it is indeed a 3mm pitch lead screw. I have ran several test cuts with different dial gears and at random engagement points and it repeat cuts correctly. So your suggestion of it should say “Any”  “Any” is the best simplification.
2. Also to my shame. I have checked and I do have a copy the Martin Cleeve book Screw Cutting In The Lathe. So I will be reading it from cover to cover.
3. Once again thank you both for your generous help

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