Metric thread fun! (Pics)
Got an odd job in,customer has a building with cast in electrical outlets in the floor.Each outlet has an Aluminum cover with a thin screw in plug to cover the outlet when not in use.Over the years a bunch of these plugs have gone missing.Mfg no longer had any replacements and the other mfgs plugs where too small.
Thread is a M 42.5 x 1.5 and the length of the plug is 1/8".They asked for 50 in Brass.
First problem was the Hendey didn't come with the 120/127 transposing gear.The boss made one up that worked,but nobody at work knows where the chart went and I didn't have time to sort through that mess.The Italian lathe is too big a PITA to thread with so......that left the Boss's HF 9x20 dumpster reject lathe.Yup,your reading right,HF 9x20
After I chased the devils out of the change gears,made a new toolpost mount and dialed the taper out of the machine it actually turned the OD to dimension with less than .0002" taper over 12"Setup and threaded the rod which went suprisingly easy.
Next fun was parting them off,whipped up some new Aluminum soft jaws for the Hendey and sliced away.
Final operation was cutting the coin slot in the face,just a round bottom groove that fits a quarter or nickel allowing easy removal from the socket.
Setup shown is a single lip cutter I whipped up,the work support is a strip of 1/8" thick dead soft Aluminum.Clamped it in the vise and used a small hammer to bend the ends around and form then to the back jaw.Hacksawed out the V-notch and milled the thickness down by .015" so only the plug would clamp.Slotting only took 15 minutes for 50 pieces.I ended up having to thread another 4" long piece to yield enough stock to do all 50,didn't have a thinner parting insert than .125",so each drop took .250" off the stock length.
Last edited by wierdscience; 08-30-2010 at 10:52 PM.
I just need one more tool,just one!