Wednesday, April 22, 2009

A Good Press Fit

Press Fit Detail
I should do an Instructable on this, but here's a brief word on press fitting. In the piece above, which is a counterweight for a dancer arm on a film stretching machine, there is a copper threaded fitting press fit into a brass part. I made this by first drilling out the copper piece to the right diameter, as seen in the video, tapping the hole for a 1/4-20 thread, and then turning the copper down to the right diameter, .318". The copper then had a shelf of this diameter, and an OD of .5". I then turned the brass piece so that the bottom had a .496" diameter hole leading into the .315" diameter hole. I put the whole assembly into the vise and pressed it together, then went at the bottom with a ball-peen hammer. Finally, I turned the center of the bottom in until the copper and brass were sitting coplanar to one another. Then it was file and sandpaper time!


I think it looks nice, if I do say so myself.

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