Tight tolerance bushings and inspection

[bob1112]

Need to make some small bushings with a small ID, .120" Not sure if these should be hard turned (HRC 58-62) or turned and treated. Also not sure how you even hold a .00015 tolerance on such a small ID? I mean, how would an ID grinder even do that? Is there any other options for this?

Also, how does a guy inspect that? Not like gauge pins will do here.

[juergenwt]

Sounds like a job for a honing machine. You will also need a go/no go plug gage.
You could also try a bushing supplier. Usually +0.0002 but ask them to select.

[Artesian]

Honing and an air gage to check the ID. You can pick up a used air gage on Ebay. Make sure to get the correct size and style of plug.
Process- Rough bore, heat treat and then hone. You should expect some dimensional change in heat treat. So, all critical dimensions / features should be finished afterwards. You might consider grinding the OD after heat treat as well.


Good luck...