calderp
Aluminum
- Joined
- Jul 22, 2011
- Location
- New Orleans
I have a casting off a drill press that had a setscrew which had been overtightened and cracked off a piece of the casting. I built it up with brazing rod (Harris Stay-Silv 15) and was going to drill and tap for the new setscrew but it appears I didn't allow it enough cooling time, it's now so hard I can't drill it with HSS. I'm sure I could get through it with a harder drill but I'm worried I will break a tap off in there and/or run into cracking issues in the future from embrittlement. Can I fix my mistake by heating it up and allowing it a proper long cool? I could either go old-school with a torch and a bucket of sand, or put it in my heat treat oven. Thoughts? If I go the oven route can anyone advise on temperatures and times? If torch what is the target, a dull red? In that area or the entire casting? Casting is not large, maybe 12"x8" with average thickness about 1/2".