Quote:
Originally Posted by Brandon Holley
Genuinely curious- have you seen another supplier provide 'fancy datum stuff' like concentricity of a gear profile -> bearing hole?
If you are talking specifically about how round bearing openings are in plates, I think you're referring to the measurement known as Roundness.
Either way, I've never seen much GD&T tolerancing appear on vendor specs before, so I'm wondering where the expectation for that information comes from?
-Brando |
Oops, I meant to add that I wasn't upset because none of the other suppliers really have them. I'm not looking for roundness on the bearing holes as they tend to be quite round, but my problem with the dog gear was the diameter was a touch bigger than I would have made it.
Knowing if stuff is really concentric can really help with design to locate features. For instance, the versa pattern thing on vex parts is very accurately concentric, but for instance, some of the recesses for fastener heads in the gearboxes for mounting aren't quite concentric with the mounting hole. In normal use, it doesn't really matter, but if you're using the plates/gearbox your own application, it's nice to know.
I wouldn't mind seeing stuff like circular runout on hubs and stuff. Whenever our kids draw a part in CAD, I have them do all the GD&T dimensions. We've got a great machinist who won't work with kids and drawings who don't have a good understanding of GD&T. As a result, we end up with a bunch of high school kids who really understand dimensioning parts and tolerances for machining and who understand how poor the field drawing FIRST supplies are.