Drilling thru rasp shank

[porthos]

just finished putting scales on a very crude knife that a uncle made in the 1940s. was told that it was made from a file/ tried to drill thru the shank end (previously heated orange and let cool) got thru one hole with a #28 carbide drill then the bit broke off. was able to install fake brass rivets and made the scales out of applewood. question that i have is ; how could i have drilled holes in the shank? the shank was .125 thick and .625 wide. so i wonder if it was a file

 

[benmychree]

The heating and slow cooling should have done the job so that a HSS drill should have been adequate for the job, perhaps it may have been a power hacksaw blade, sometimes HSS.

 

[ericc]

Sometimes farrier's rasps are case hardened, and can have a very hard skin. If you grind with a small die grinder, you might be able to remove the hard skin and even heat the metal a bit. If it shows some temper color, all the better. When I have to do this task, I usually have better luck with a sub-critical anneal. Heat with a torch, but only to the dullest of red color, barely visible. Or, use an upside down junk nail spun really fast in the drill press. Then it won't matter how fast it cools. It will get softer. Maybe 30 RC, but that's enough for a HSS drill, especially with the aid of some soluble lube and a touch of hydrochloric acid if really desperate.

 

[porthos]

well thanks guys. its done now with a broken carbide drill covered with fake brass pins. i don't think that i'll run across anything like that again.