Can I add an allowance to a driven dimension?

roman_olesnicky

I have a dimension of a part whose width is driven by the dimension of its mating part. I want to make this part, say, 0.1mm narrower, while retaining the "driven" aspect. If I am machining this, I make the tolerance +0, -0.1, that's easy. But if I'm going FDM, I need the base dimension to be smaller in the base model. Linking both mates to a variable is one way, but I think this prevents me from simply projecting the first sketch onto its mate.
How is easiest to do this?

eric_pesty

I'm thinking a "move face" after the projection might work.

glen_dewsbury

You may be looking for an offset in an extrude.

roman_olesnicky

Thanks, Eric. That would work and be pretty straightforward for a simple flat interface, consistent with my original post. As might glen’s suggestion in particular cases. But elsewhere I have Part A registered to Part B by a number of small circular bosses on Part A, fitted to mating holes in Part B. I need to make the mating hole in Part B say 0.1mm larger than the boss diameter of the boss on Part A, which is the driving dimension. I can of course project points from Part A sketch to Part B sketch, define a variable, and draw separate circles on each sketch with the appropriate related dimension. But is there a quicker way?  Wouldn’t it be neat if I could right click a driven dimension and choose “add a bit”!

eric_pesty

If you have a number of bosses and they are identical you should be able to draw one pair of boss and recess and use a pattern to create the other ones...
You might also be able to do this with a boolean operation, which has an offset feature.

Are you able to share a link to your document?