Friday 12 May 2017

Group check-valve cap

The last piece????

Ok, well not technically the last piece, but the only one standing between me and an entirely functional machine.

The check valve cap for the group is fairly straight forward. I had ordered a couple of carbide 60 degree threading inserts and a holder a few months ago to eliminate the guess-work. I had initially gone "old-school" and used a jig to grind a thread cutter from tool steel. It works, but it isn't perfect and it can't thread as close to a shoulder as the insert. Having turned down some hex stock to the major diameter of the M18x1 thread and added a relief groove at the shoulder I set up the lathe to cut the thread in 29 passes and left it to its own devices.


























The hex stock is a short-cut - ideally, I would machine a smaller concentric hexagon on the top as there isn't enough room to get a socket driver on when it is installed in the group. It will do for now however.


























... and that is it. A complete working machine! I threw together a temporary drip tray from some aluminum sheet, metal duct tape and copious use of a hammer - file under ain't pretty, but works.





Now, while I wait for sheet metal done by my betters, it is time for the somewhat drier (literally, not metaphorically) work of testing, coding and electronics.

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