Drilling hardened stainless

zippinaround

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Someone told me ages ago to sharpen a masonry bit and it would drill through hardened steel , yesterday I finally put it to the test after ruining 3 hss bits actually made for metal and can confirm it works a treat, even roughly sharpened with a grinding disc .
 
I've not had good luck with that. it's easy enough to just anneal it and then heat treat it again when you're done adding holes
 
I've not had good luck with that. it's easy enough to just anneal it and then heat treat it again when you're done adding holes
how does one go about doing that? i was really surprised it worked was just a cheapo masonry bit too.
 
anneal, drill, harden, temper

to anneal heat it to a dull red and let it air cool or bury it in sand, to drill you use a drill, to harden heat it cherry red or until it doesn't attract a magnet and quench in oil or water depending on the alloy, and to temper heat it in the oven to a faint straw color. if done properly, it'll come out about 62-65 rhc, which is about as hard as a knife. for a softer hardness, you temper at a hotter temperature. tempering it to a blue color will land you about 55 rhc, which is about as hard as titanium can get
 
I make gear and sprockets and get stuff flame hardened ..from nice silver steel to brown red blue color when it comes back it will kill a band saw blade in a second really good drill bits go blunt in half that .so we do all the work to the sprockets /gears before thay gets flame hardened . carbine drill bits work on hard metal even to drill out a drill bit or tap.
 
I make gear and sprockets and get stuff flame hardened ..from nice silver steel to brown red blue color when it comes back it will kill a band saw blade in a second really good drill bits go blunt in half that .so we do all the work to the sprockets /gears before thay gets flame hardened . carbine drill bits work on hard metal even to drill out a drill bit or tap.
you have any lying around you can drill a hole in and a cheap masonry drill bit the one i used was 1.49€ as part of a set ultimate cheapo alternative
 
Just to let you know, to drill with carbide you need to spin them fast 2,500 or better. Chips will fly white hot but works great, i use Milwalky bits seem to last longer..............Curt
PS. to drill stainless you do just the opposite really slow, never tried carbide on it i always use good colbalt.
 
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Nice bit of info bud cheers , seems like a lot more work than just sharpening a masonry bit though .
you need lots of speed to drill hardened steel with carbide and what I find ends up happening is the brazing holding the carbide tip to the drill shank ends up softening and slinging a piece of hot carbide across the room into whichever pile is most flammable. could just be the particular bits I tried, but with that experience I'm not about to go experiment with different brands to see which one doesn't nearly burn down my shop.

it's easy enough to anneal and re-harden steel. it adds an extra 20 minutes to the job and I don't need to ruin my good masonry bits.
 
[QUOTE="butre, post: 420453, member: 2246]you need lots of speed to drill hardened steel with carbide and what I find ends up happening is the brazing holding the carbide tip to the drill shank ends up softening and slinging a piece of hot carbide across the room into whichever pile is most flammable. could just be the particular bits I tried, but with that experience I'm not about to go experiment with different brands to see which one doesn't nearly burn down my shop.

it's easy enough to anneal and re-harden steel. it adds an extra 20 minutes to the job and I don't need to ruin my good masonry bits.[/QUOTE]
Haha excellent reply , If I had a gas torch or anything to heat it I would definitely try it , but I'll add I drilled very slow about 1500rpm @ a guess maybe 3000 at most and was squirting it with 2 stroke oil
 
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