DOUBLE TAPPED HOLE TROUBLE

[patrjck]

Whenever a hole is tapped from both ends, Inventor 2012 (and previous versions) has a number of problems.

- In a recent part I made, I added threads to both ends, but when I generated the drawing I noticed the thread lines were only on one side.  When I reopened the part, the thread had jumped to the other side.  Try as I may, I was unable to add threads to the opposite side where they belong.

- In another part, I had a thru hole with a fixed depth 1/4-20 tap.  When I added thread to the back side, it defaulted to #12 even though it should be smart enough to recognize its own hole size!

- When I called out the threads in the drawing, BOTH sides called out #12!  What if I had wanted 1/4-20 on one side and 1/4-28 on another?  The thread could be different.  Inventor needs to pick the thread that's "on top".

[ToddHarris7556]

Interesting.

I can't offer an explanation or fix, but confirmed behavior, somewhat.

Single hole, 1/4-20 fixed depth tap.

Create drawing with section thru hole.

Hole notes on both thread feature and hole are fine.

Go back to part, add 1/4-28 thread to other end of hole.

Drawing shows both threads.

Add hole note note to new thread, it shows #12 hole.

Return to part, fix both hole and thread feature back to 1/4-20 & 1-4-28.

Drawing now shows 1/4-28 all around. (Both threads) even though the part still shows correctly.

[patrjck]

This is the part file.  I have tried and tried to tap the other end, but the thread keeps jumping to the first end.  When I create the drawing, it only shows tap marks on one end, consistent with the visual part appearance.  That should help you recreate the other half of the problem.  I just submitted prints with penciled in tap marks.  🙂

[blair]

I believe the problem starts with how the hole is created within IV and the data for the hole is stored. The thread for the back-side of the hole must really start at the bottom of the first hole. IV's just not that smart, try a front hole of a set depth, not all the way through and create a new hole for the back-side of a set depth, not all the way through.

Holes have a start side and direction, I think this is giving you your problem.

[rdyson]

Is this what you're wanting?

[patrjck]

RD: yes, I don't know how you did it, but I initially had it look like that.  Then something happened and the thread jumped to the other side and try as I may it wouldn't come back. 

The double blind hole thing is one solution, but then the hole callout won't be for a thru hole.  I think I've tried a thru hole and a blind hole of the same size and Inventor didn't like that.  For now I'm sticking to penciling in and leader text.  Unless RD reveals his secret!

[rdyson]

All I did was edit the two thread features. Reversed direction and edited their specification 

[patrjck]

Oh I see, the red/black arrow reverses the thread direction.  I've never had to do this because Inventor usually knows which way a hole is pointing, but in this case, being the bottom of the hole, it got confused.  Thanks RD!

Autodesk people: I guess this fixes the main issues, but it would still be nice if the IV got a little smarter, as you say.  One thing that happens frequently for me is having multiple holes on top of each other and having trouble getting them to call out.  This happens when I drill the hole for a pressure sensor for example.