Our parts making continues! We had a sort of run of the mill (sorry) part to make, and I thought the setup and how we decided to make it was interesting.
Here are the parts, tube plugs being made on our prototrak knee mill:
Those little plugs will end up welded in the ends of some tubes, and center through hole in each will be tapped. for reference, the OD is (I think) .620". We needed 24 total.
Because the OD and surface finish of the plug, and the diameter of the center hole had some fine tolerances these parts were poor candidates for plasma cutting. The plasma cutter is slick but doesn't do fine detail in thick aluminum well. Turning the parts on a lathe is the obvious choice however our lathe was busy at the time and, for a variety of reasons, wasn't a great solution for this part. That leaves the cnc mill!
Entering the program in using the prototrak 'conversational' interface was fairly easy, if a little laborious. The 24 hole array was drilled first and ran short wood screws into the wood backing plate to hold each part in place after it was trepanned out of the plate.
For those curious; the tool is a HSS 3/16 end mill with no special attributes. It ran at 2000 RPM, .1"ish doc, 6ipm with a mist coolant and was pretty happy.
The mill:
