retaining thread lead

[argomch]

I was wondering if anyone has any information on retaining thread lead between 2 tools programmed at different SFPM. I'm working with okuma turning centers, 5020L controls. It seems any alteration to the threaders SFPM causes the threading start point to change, thus obliterating the thread form. Is there a formula that calculates the start point ? is it a relationship of RPM/StartPointZ/TPI?
There are 2 things im hoping to achieve with this knowledge. 1) be able to use dual threaders to rough/finish and 2) be able to adjust the parameters on a second tool used for blunt starting threads if the threading tool parameters need to be adjusted.
Thanks in advance !

[star-turn]

what is your reasoning behind 2 tools for a thread ? if you are doing 1000's off and want a finisher ( which i have never found to be needed ) then use the same rpm for the second tool and only take 1 or 2 passes in g92 or set & Q to full depth in g76
if tools are set/probed correctly you will have a good thread.

For blunt start you need a grooving tool - if you start this 1/2 a pitch in from your threading tool start position and run the g76 or g92 as you did with the s/cut tool it will remove the first thread ( you only need to change the end position )

[argomch]

Thanks for the reply !My primary need is for the blunt thread start. The problem im running into seems that if i run my groover at the same RPM as the threader the pullout is too long. i hope to run it around half the speed of the threader, which seems to create an acceptable pullout length. Unfortunately, getting the thread starts aligned with the different RPMs has been a shot in the dark. I also feel that at some point we'll hone in on better SFPM for the threading process, but each change is going to require the same shot in the dark process to get the thread starts aligned.
Yes, i have 1000's to run .... 3400 at this point and a potential 9-10k per year. They are big (in my world) 3-1/2"-4 Stub Acme threads.