Tapping a welding assembly . . .

[Hypoluxa]

forgive me if this is a repeat thread, I was unable to find an answer while seaching.

I have a simple welding assembly: a plate and a cylinder (boss).

The boss has a through-hole of 0.3125.

The plate has a hole of 0.332.

The boss is welded to the plate with the holes being concentric.

I tried to preform a machining operation by creating a sketch, projecting the geometry of the holes, and creating a threaded hole at the centerpoint projected.

The thread size I had selected was 3/8-16, and this is where I run into the issue. When modeled, a tapped 3/8-16 hole measured 0.307 (which I assume is the threads minor diameter). Obviously, 0.307 is smaller than the two concentric holes and Inventor is unable to create the tapped hole.

According to the tapped drill size chart found in any machinist reference, 0.312 is the required drilled hole diameter to tap a 3/8-16 hole. Am I missing something as how to create this tapped hole after welding in Inventor?

I know I could make the holes smaller on the Plate ans Boss, but then they would not accurately depict what is being made in out shop. Any help is appriciated, thank you.

[karthur1]

The reason the hole fails when you apply the 3/8-16 tap to it is because in the Threads.xls file, the minor diameter is .307.  There is no way to add the material back in the weldment (can only remover material). 

Without getting into a bunch of complicated substitutions and derived parts, I think I would just make the hole smaller so you can tap it in the weldment.  For the plate (with the now .307 hole), manually place a note on its idw to callout for the hole (if you are allowed to do that).

If you dont want to do the manual note, then make the part in the weldment a different part than the one that you detail.

I wouldnt recommend changing the threads.xls file.

Kirk

[Hypoluxa]

Is there a way to select a different option than "minor dia" of a threaded hole to be displayed? (e.g., Basic, Major)

Am I correct in assuming that by changing the Threads.xls, it may have a negative effect on existing files?

Thanks again for your help.

[kstate92]

IIRC, Application Options has a choice of tapped holes showing the pilot drill diameter instead of the minor diameter.  But I think the tapped holes may not show correctly in drawings (unless they fixed it in versions younger than mine).

[Hypoluxa · Accepted solution]

ahh . . .  Document Settings > Modeling > Tapped Hole Diameter . . .

from here, I'm able to set what I would like displayed . . . and it worked. The concentric holes now display the 3/8-16 thread.

Thank you both for your help. Much appriciated.