What did I do? Hardened Iron

Hi Guys, Once in a blue moon welder here. I made two brackets with 3/16" x 1-1/2" angle iron. All went well, I drilled some holes and checked fit, then when I went to drill the holes larger, it seems like the iron is hardened and I can't drill it. I did water cool it after welding, but it seems like my first set of holes drilled ok. When I went to redrill, it was to hard to drill. I tried heating the whole thing up to dull cherry red and let it cool slow, but I still can't drill my holes larger. What is going on? I need to know before the next blue moon :-)

MikeK

Reply to
amdx
Loading thread data ...

Dull drill?

Seriously though, one frequently drills a hole with a smaller drill and all goes well. then tries a larger drill and it doan work! Usually a matter of cutting speed.

Cheers,

John B. (johnbslocombatgmaildotcom)

Reply to
John B. slocomb

Welding and plasma does a number on steel and if it can harden it will.

If I need nice holes, I drill them. If the holes are nor drill size I use my cnc plasma to cut them. But I learned not to punch pilot holes for a drill press - the metal hardens nicely.

A grindstone - like a cone might grind the holes a bit larger and then a drill can take over. Or if sheet - try a cone drill.

I'd drill the holes before welding and if not - use a cone drill - or get a round file and open the hole up a bit then try a drill.

If stainless - drill first no matter what. Chrome oxides are tough!

Mart> >

Reply to
Martin H. Eastburn

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.