Best Practice to Model an Imperial Sized thread

peter_morris

Hi,

I've some experience with Onshape, but am definitely not a competent CAD driver. 

I'd be grateful for advice on the best way to model both internal and external threads.  For internal I know I can use the hole feature, but when I try to model the nut for a 16tpi 1/2" thread I find that the only choices I have are 13, 20 and 28tpi.  The size I've quoted (1/2") is the major diameter of the external thread. Since I'm modelling the nut it would be good to do the same for the bolt.  What I'm trying to do is create the model in such a way that the 2D drawings accurately reflect the object. Any advice on the best way to manage this scenario would be gratefully received.

One other feature that might be a suggestion for improvement would be the inclusion of BA sizes when creating holes/bolts.

Many thanks.

john_mcclary

You won't be able to add thread pitches to the standard hole list. 

You might be able to copy the hole feature and add it there. But i'm not sure if it will even show up correctly in the drawing. That method is probably over both our heads.

So that only leaves you with manually writing the thread callout in drawing (what I would do)

Or

Draw the threads in the model then dimension them in the drawing (wouldn't do unless you can handle the performance hit) 

peter_morris

copying the feature script and amending it would be a way forward - and I like a challenge (though I agree it might be beyond my limited skills). 

I'll investigate adding the call out.  I had thought about using it, but my limited investigate simply added a circle with 2BA in it, but no arrow to identify the hole I'm trying to describe!.