1/2" ISO PIPE THREAD

[stephengibson76]

Inventor gives me 12.7 drill hole but everything I am referencing recons about 19mm, is it a mistake or am I putting the wrong hole type onto my model?

[mpatchus]

well a NPT 1/2 hole gives me .721 [18.323 mm]

while an ISO Rc 1/2 comes in at .733 [18.613 mm]

[Paul-Mason]

Pipes are measured by nominal, 1/2inch in your case, bore of the pipe from the thred.xls

Eternal thread for 1/2 NB Pipe

G 1/2		1/2x14 BSP	G 1/2x14 BSP	14	A	20.955	20.671	19.793	19.651	18.631
G 1/2		1/2x14   BSP		14	B	20.955	20.671	19.793	19.509	18.631

Internal thread for 1/2 NB Pipe

A	18.631	19.172	19.793	19.935	20.955		19
B

So the dimensions you have give in your post are corect.

[stephengibson76]

I think it might be a mistake, put a 1/2" ISO pipe thread hole into a model, then slap a hole note on it in the idw and it tells you to drill a 12.7mm hole which is wrong

[Paul-Mason]

From a hand/pocket book that I have "Zeus Precision"

The nearest BSP size to 12.7mm tape hole is for a 1/4 Pipe (actually  11.8mm recommended, 11.75 Alternative for tapping and 17/32 for clearance)

As for the recommended Tapping drill for 1/2 Pipe

BSI Recommended 3/4in Dec 0.75

BSI Alternative 19mm Dec. 0.7480

Clearance 53/64 Dec 0.8281

I have also checked these against the BSP in thread.xls, I have some additional thread types added to the one that come with Inventor,  the seizes as give above are CORRECT in the thread.xls file.

A 9/16 BSF thread M14 thread are the ONLY two that I can find in the thread.xls file that require at tap drill diameter of 12.7mm

Conclusion is that there is defiantly something wrong with what you have in you part thread/hole callout in you IDW file and it's not bad data it the actual part it's self that's wrong.

It may be better if you can post the IPT file and the IDW file so that we can have a better look at them and give us a better induction as to where it is wrong.

[stephengibson76]

Attached is a file but its 2014, see the image below, the 12.7 is the tap size direct from the hole note

[Paul-Mason]

I  hope that this might help explain things as to how inventor come up with the dimensions for a BSP threaded hole

[mikesar86]

I would like to add 3''  BSP Pipe Threads at thread.xls

which data is recommended?