Metric Threads

[jackson]

Just have a question probably a dumb one but never the less a question. i dont do much metric threading and when i do i just kinda fug my way through it. i though it was about time i asked how do you convert or figure out your TPI on a metric thread the one i am doing today is a M18 x 1.5 6g

thank you

[M-man]

25,4 / metric pitch = TPI....

THread dia -(0.1*metricpitch) /25.4 will give you a good dia of shaft before threading..
Take 18-1.5 to get bore dia for ID thread.

[Geof]

Another way to calculate pitch is use 1.000mm = 0.039370" so 1.5 mm is 0.059055".

[jackson]

Originally Posted by Geof Another way to calculate pitch is use 1.000mm = 0.039370" so 1.5 mm is 0.059055".

yeah it took me a min. but i figured it out then take 1. / .059055 = your tpi

and M-man's way works to. thanks i appreciate it

[jackson]

Originally Posted by Geof Another way to calculate pitch is use 1.000mm = 0.039370" so 1.5 mm is 0.059055".

ok i come up with a diferent answer doing it M-mans way the way you show it comes up 16.949 tpi his it comes out 16.3333 the 1.5 / .03937 is the way i origanly went with

[Geof]

My calculator gives 25.4/1.5 = 16.933333

1.5 * 0.03937 = 0.059055

1/0.059055 = 16.933367

If you want to get really precise the 0.03937 is only an approximation. It is actually 1/25.4 = 0.03937007

So 1.5 * 0.03937007 = 0.0590551

1/0.0590551 = 16.933338

[jackson]

Originally Posted by Geof My calculator gives 25.4/1.5 = 16.933333 1.5 * 0.03937 = 0.059055 1/0.059055 = 16.933367 If you want to get really precise the 0.03937 is only an approximation. It is actually 1/25.4 = 0.03937007 So 1.5 * 0.03937007 = 0.0590551 1/0.0590551 = 16.933338

I see i was not finishing the .059055 i was just using .0590 that makes more cents
thanks Geof