Help on simple problem [solved]

cadcam1

I am trying to link the inner diameter of a ring extrusion to the

inner diameter of a shelled rod. In the sketch the diameter seems to

be constrained to the shell surface. However as soon as the sketch

is extruded the inner diameter of the extrusion jumps to the outer diameter

of the shelled rod. Is there a way of maintaining the link to the inner diameter?

 Many Thanks

bruce_williams

Good Morning @cadcam1 and welcome to the forum.  This would be easier for us to help with if you share a public document.  See instructions here https://forum.onshape.com/discussion/9107/forum-post-checklist-read-this-first#latest

cadcam1

Apologies, 

https://cad.onshape.com/documents/4a5475e45542ebbcf0e79818/w/a434227dd4a58866f0879769/e/b0c910333794e8ad4a995f04

bruce_williams

I am getting a 'does not exist or you do not have permission to access' error message

Please confirm it is public and share again.

cadcam1

Apologies again, reset public/shared access . I hope

bruce_williams

good share now

Onshape does things a little differently (and better once you know the workflows).

Extrude works on regions and in your case you are selecting the outer of two regions on Sketch 2.  If you also select the inner region you will get the correct ID.  As option you can just select 'Sketch 2' from the feature list.

Also, if you want to join the two parts, select 'Add' and Merge scope 'Part 1'in the Extrude.  That Boolean joins into one part.

See video example below.

cadcam1

Thank you, very helpful, Sorry for such a simple question