PTownSubbie
Member
Alright as some of you know, I have been working on the kitless pens....Tonight, Jason and I did one and the cap doesn't fit on the body. I know it is the cap because if I use a good pen, the bad cap won't thread on the good body.
The cap was drilled at 11.2mm to fit the M12x0.8 triple start tap. The tap was used to create the threads. I used a tap guide to maintain pressure on the threads. The cap was then placed on the mandrel and turned to size. I have been using pressure from the tail stock (wondering if this is causing problems). The threads after turning are now reading 11.7mm in diameter when they should be 11.2mm.
This has happened twice now. Both with the last two pens I have made. The only thing that I changed was the way the tailstock pressure was added. Can you apply too much pressure? And would that possibly cause vibration that would somehow strip the threads out some?
Those that turn your kitless on mandrels, do you use any tailstock pressure? If so, how do you apply it?
I will try some more things tomorrow but I would really like to figure this out so I stop ruining blanks.....
Thanks!
The cap was drilled at 11.2mm to fit the M12x0.8 triple start tap. The tap was used to create the threads. I used a tap guide to maintain pressure on the threads. The cap was then placed on the mandrel and turned to size. I have been using pressure from the tail stock (wondering if this is causing problems). The threads after turning are now reading 11.7mm in diameter when they should be 11.2mm.
This has happened twice now. Both with the last two pens I have made. The only thing that I changed was the way the tailstock pressure was added. Can you apply too much pressure? And would that possibly cause vibration that would somehow strip the threads out some?
Those that turn your kitless on mandrels, do you use any tailstock pressure? If so, how do you apply it?
I will try some more things tomorrow but I would really like to figure this out so I stop ruining blanks.....

Thanks!