How can I calculate tolerances for metric thread pitch diameter?

# Thread: How can I calculate tolerances for metric thread pitch diameter?

1. ## How can I calculate tolerances for metric thread pitch diameter?

Hello experts
What's the formula for calculating the max/min pitch diameters for a given metric thread? The tolerance grade is 6g. I've been trying to find a COMPREHENSIVE reference table for thread tolerances but to no avail (a well concealed secret ). Is there any software available for calculating thread max/min/pitch dimensions and tolerances?

I'd be very thankful for any help.

2. Originally Posted by myhäje
Hello experts
What's the formula for calculating the max/min pitch diameters for a given metric thread? The tolerance grade is 6g. I've been trying to find a COMPREHENSIVE reference table for thread tolerances but to no avail (a well concealed secret ). Is there any software available for calculating thread max/min/pitch dimensions and tolerances?

I'd be very thankful for any help.
hi

the anser
:-)

3. Originally Posted by agapios
hi

the anser
:-)
Thanks but that's not really the answer I'm looking for - no mention of calculating tolerances. Let's take an external M48x3 thread, for example. The maximum pitch diameter is 46.05 and minimum 45.86. How are these values derived?

4. NUMBER = size of tolerance field. The position of the field in relation to the "Zero" line (Nominal size) is given by a LETTER representing the size of the "base deviation".
Base deviation is the upper deviation (external) or the lower deviation (internal) thread.

______
I
I Tol.
______

------------------Nom. Size

______
I
I Tol.
______

To designate a thread the tol. number and position are given in reverse i.e. 6g (g6 for shafts etc)

It gets pretty complicated. So if you really need it get a book.
Order from "Beuth" in English pocketbook Nr. 45, ISSN 0342-801X English
ISBN 3-410-11827-6

Some help is here:http://euler9.tripod.com/bolt-database/22.html

Pitch dia 4h = 46.051/45.919
6g = 46.003/45.791
8g = 46.003/45.668
Good luck - Juergen

5. Originally Posted by myhäje
Thanks but that's not really the answer I'm looking for - no mention of calculating tolerances. Let's take an external M48x3 thread, for example. The maximum pitch diameter is 46.05 and minimum 45.86. How are these values derived?
for all that you neet 1 ISO and 1 DIN.
the DIN 13 for the thread
and the ISO 286 for the tolerances

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