help drilling handle holes

[kbaamigo]

I have been tinkering with making knives out of an old 30" saw blade. I use a hand grinder, cut out with cut off blade and then grind to shape slowly to not loose temper. I am heating spots with torch and let cool to remonve temper but still having problems drilling holes for pins. Sometimes I get thru and others I get halfway. I do not have a carbide bit and wondered if that will take care of it. Suggestions needed, please and thanks.
Kent

[Bladepeek]

A carbide bit will definitely cut through. I can drill fully hardened steel with one if I go slowly. They are fragile, though, so be sure to use a backing plate (scrap steel) to prevent the bit from jumping through and grabbing on the edge of the hole.

[milehi101]

I use Ceramic spade drills and they work fine.  Just let the drill do the work and dont push them and they will cut hard steel fine.

[kbaamigo]

Thanks guys. Love the small town but it has it's downfalls, can't find a bit here so will have to order one.

[kbaknife]

Try this before ordering a bit:

I see that you say sometimes you get through and sometimes you don't.
I do not know how familiar you are with the hardening process of going from austenite to martensite.
According to the particular alloy, it can be a lot about TIME.
Meaning, if you have some alloys in the condition of austenite - around 1500 degrees - to get them to convert to hard martensite you must remove the heat quickly.
In other alloys, conversion to HARD martensite can occur simply by letting it cool in air.
So, if you are working with a saw blade made of 15N20, it can actually air harden.
The point is to NOT!!! get it heated up to the point where it will air harden.
You may be getting some of those spots too hot.
Look, I've been making knives for a little while, and have yet to find the reason to use alternative "solutions" to drill a hole.
Just use your torch - but use it right!
Turn all the lights off in the room.
WARM up the location for your hole just to the point where you see a dull red. That is about 950-1000 degrees.
Back the torch away a little and try to hold it at the temp for about 30 seconds.
Keep a magnet handy and occasionally touch the spot. You really want it to retain full magnetism.
If it goes non-magnetic, then you have exceeded 1418 degrees. You're too hot.

So, get it dull red in a dark room.
Back your torch away and try to hold it there for 1/2 minute.
Let it cool off to black and quench in a bucket of water.
Repeat.
Repeat.
Repeat.
It will take you about 5-10 minutes to accomplish this.
But you won't have to buy any expensive drill bits.
Or suffer any aggravation.
What you are doing is a shade-tree shperodizing anneal, in that you are clumping up the carbon within the blade making it machineable.

[kbaamigo]

Karl,
Wow! That is great info, I just thought heating red and letting cool took the temper out! I am getting way too hot. I will definitely give this a try and thanks a lot!!
Kent

[kbaamigo]

Had to be a little careful keeping heat away from blade so cut time a little short on closest hole but it worked great! Thanks!

[kbaknife]

Originally posted by kbaamigo:
Had to be a little careful keeping heat away from blade so cut time a little short on closest hole but it worked great! Thanks!

I use a C-clamp just above the ricasso and set the blade into a container of water leaving everything else above the water.
The heat can not reach the blade in any way.

[kbaamigo]

Some times I think I know just enough to be dangerous! Did two more blades this weekend and all went well, thanks.