September 28, 2016
So I’ve made a piece of metal that looks like a knife, out of a old file. You can see my progress a here. Things have been going well. Now, however, I am struggling with drilling holes for the pins.
I’ve tried drilling as slow as my Ryobi drill press can go. I’ve tried my intended bit size of 1/4″, I’ve tried using size smaller bits. I’ve tried using as small as a bit as I can (it broke in half).
My next thought is to temper the knife for a few hours at 400 degrees. Please note, I have not yet hardened the blade. I have confirmed through destructive testing that the metal hardens further in oil, but the file had no remaining markings to identify the manufacturer.
Is this a good idea? Should I go even hotter? Will it matter? I did forge the knife mostly on the anvil so it has been through many heats and I heated it up to white hot and let it cool three times before taking it to the bench for grinding.
The Bumbling Blacksmith
September 28, 2016
So this is random. I am answering my own question. I spent some time on youtube today and found this video “Best Drill Bits For Metal, Stainless Steel and Hardened Steel” by Wayne Winton.
What an awesome video, it gives a really great picture of why I was running into problems and what to do to get past it.
The short answer to my question is to start a small hole via either punching it or using a standard bit, then use a masonry bit of all things. If you don’t pre-start the hole, then the masonry bit will wander all over the place. A masonry bit is super dull compared to standard bits, and was able to out drill all bits that he tested outside of bits made entirely of carbide. Bits with diamond and titanium plating did quite poorly in his testing which is the opposite of what I would have anticipated. I will be making a longer post on this topic for my blog at ramforged.com if you wish to learn more and see pictures. I should get it up sometime tomorrow.
The Bumbling Blacksmith
December 27, 2014
Well, I would suggest, if that doesn’t work, to anneal the knife completely. And by that I mean heat it up and stick it in some insulating material like a bucket of wood ash, a wrapping of kaolwool, or some vermiculite. That’ll soften it up as soft as you can get it.
It’s possible you hit a hard spot in the metal, which happens from time to time. One way to get around that is to heat it up to a gray color (past the blue), which may relax the material enough to drill through.
My Youtube channel: Cave of Skarzs
Just having some fun messing around with whatever I have a mind to do.
November 14, 2010
Mark, Many things to work on here, but let’s try drilling first. Your steel may be too hard if you wrecked a bunch of bits. First grind off the fire scale, then a torch tempering through the temper colors until it turns clear should let you drill it. I use Cobalt bits from the local fasteners shop here. They work much better than High Speed Steel bits. Drill, clamped on a wood block to lessen the chance of catching the bit when you break through, thus breaking a bit, and also to protect you if it catches and spins as can happen if unclamped. Cool bit with a bit of water while drilling. Next, you only want to heat the blade to just a little past non magnetic as checked with a magnet on a stick and then let it cool til most of the color is gone then re do for three normalising cycles. If you are heating to a white heat you are undoing everything you are trying to do in a normalising cycle, and are growing the grain to a large weak structure, that will cause a broken blade later. With proper thermal cycles your grain size should be so small that it looks more like flat grey paint when broken, than gritty sand as in your broken handle tip photo. For home knifemakers I highly recommend two books by Wayne Goddard, a former NWBA member. They are The Wonder of Knifemaking, and The $50.00 Knife Shop. They can be found fairly cheaply on Amazon. You do not want to heat your blades past a bright salmon color seen in subdued light if possible. You can get away with overheating mild steel, but with high carbon steel you want to minimize grain growth by keeping your forging and heat treating heat in the bright salmon and cooler ranges, but do not use any heavy forging blows below a bright red. As far as your tang being too thin at the end, many knives used in the fur trapper era of this country had tangs tapered to nothing at the end, but full thickness at the blade/tang junction, and lasted very well. I have several from that era and they are still working. I hope I hold up as well! If you have further questions that I can be any help on feel free to contact me.541-954-two one six 8.
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