Another day in manufacturing land. Temps down a bit this morning so the plant floor was comfortable for a change.
Get called to a line. We have a special tool that feeds a fastener and torques it to spec as part of an assembly station. The tool bit is 12" long, 1/2" dia, has a 7/16 hex on one end, and a 5/16 hex that drives SHCS. Obviously custom tooling.
Item has a 3 week lead+shipping time. The last time I changed it I had two spares on hand. Today, I had zero.
Well that stinks. Multi shift operation, no one admitting to using the last one.
Check with supplier, I can get it in 2 weeks if I expedite. Okay fine order some.
Take a worn out one I had in my tool box. I hold on to the old ones since I figure this is some decent steel to do this job and I'm just paranoid that I tend to keep stuff that might go another lap or two just in case. On a PM you replace things that might not be totally used up to avoid down time.
What to do. We have a bunch of 5/16 hex extended bit stuff for other operations. If I drilled a hole in the end of the tooling, I could silver braze portion of that in and make a good tool. One problem, my special tool is hard and tough.
Okay, do what has worked for me many times. Use oxy/a torch to take detail red, check with magnet, air cool, then machine.
Well I did that, set the tool aside, had lunch, it was still warm 30 minutes later.
Turn off the hex bit end. Chit, this thing is hard. Harder than some dowels I've turned into step pins for locating things in my cells. Must be some sort of air hardening steel?
I know we stock #3 carbide center drill counter sinks. I had a bad feeling since the tail stock ways on this lathe I use is whipped. Two tries, broke off the reduced diameter part of center drill. Too much droop in tail stock.
Went to a 3/8" dia carbide spotting drill. 90 degree point. It cut wide due to the tail stock droop and there is that 90 degree taper in bottom of bore.
I managed to change to a collet chuck before I got called away. Tomorrow, I'm going to put a matching 90 degree taper on the piece of bit I'm going to braze in. That should nicely center my bit in the over sized hole and allow the few thou a silver braze likes for a good bond. Also, I can keep the heat away from the working end so I don't affect the heat treat.
Wes