coventry die head m8 1.25 1/2″

[lug lordParticipant @luglord]

I thread a lot of 8mm stainless 316 did a bar today and i noticed the 1st cm of the thread is just mashed like its been ground down the nut just slips over the end . I had to cut this off and re cut a chamfer on the thread afterwards is this because maybe chasers are not sharp enough cant figure out whats gone wrong.

the rest of the thread was ok just that 1cm was no good almost like a mm had been turned off the end

thanks

[lug lordParticipant @luglord]

[Nick HulmeParticipant @nickhulme30114]

It sounds like it didn't initially feed correctly and because of that stripped off material down to the base diameter of the thread.
How do you prep the bar end for threading?
I'd be tempted to try a test piece and if that works OK just put it down to an unknown variable.

– Nick

[lug lordParticipant @luglord]

i use a chamfer tool to cut a neat chamfer on the end of the bar . I think maybe next time i will cut a lighter cut on the first pass then re adjust for a final cut see how that works out

[lug lordParticipant @luglord]

i have also changed the chasers for what look like sharper ones

[JohnFParticipant @johnf59703]

Hi don’t forget there is a roll over lever on your die head so you can take a 1st ans 2nd cut no adjustment between cuts is necessary

John

[lug lordParticipant @luglord]

cheers yes i do use the lever but i might try taking lesser cuts 1st pass .my chasers are not the correct rake for stainless steel so might be hard on them i believe i should use am5 or as but i am just using the standard s20

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