Thread: Drawknives

Andy I really like this idea.

Can you add some info about the type of steel you are using.
Do you temper the blades?
What about the overall dimension of the drawknife?

That the problem with posting good ideas, some bone head always asks more questions.

Hi Knucklehead,
I nearly always use car leaf springs for tools like this. The welding of bolts to the spring steel hasn't caused any dramas... I preheat the local metal first, but there are special (low hydrogen?) welding rods available. Never hammer spring steel without heating to forging temp!!
You can find heaps of info in books and on the Net about the tempering process, including the right colour for certain tools: the following is my rudimentary method.
After forging, welding grinding etc, I always normalise or anneal the tool to remove stresses. Basically a dull cherry red evenly throughout, hold it for a while, then cool slowly in ashes, Kaowool blanket or vermiculite overnight.
The next stage is hardening followed by tempering, which I do in two seperate stages. (real blacksmiths, and those who know the tricks do this in one go, by part cooling and watching for colours to reappear...beyond this little black duck!). Heat the tool evenly to cherry red, plunge it into quenching oil, or a brine bath, moving the piece so the cooling is even. Don't use standard engine oil, as it will go up in flames!!:eek: A saturated saline solution is what I use, but still get the occasional failure, meaning cracked steel. I think it depends on the type of steel, how much shock it can take. Clean the black scale etc around the blade proper, back to shiny steel, using cloth backed emery paper, so you can see the colours. In a darkened room, reheat the body of the blade back somewhat from the edge, using oxy or a MAPP torch. You need to get an even band of colour in a line through the blade, no hot spots! Watch for heat colours to appear, and they will draw through the tool towards the thinner edge. When a straw colour reaches the edge, quench it quickly, dropping it edge first into the coolant, and move it about. The colour should be frozen onto the steel, so you can see if you got it right! If not repaet the process..
Good luck!

Originally Posted by Andy Mac

After forging, welding grinding etc, I always normalise or anneal the tool to remove stresses. Basically a dull cherry red evenly throughout, hold it for a while, then cool slowly in ashes, Kaowool blanket or vermiculite overnight.

Have you tried using washed sand instead? 'Tis what I use but my odd bits'n'pieces don't need tempering and any cooling short of quenching is normally good enough. It works well enough for the occasional wrought iron fiddle-work & hinges on my cabinetry... as well as the odd costume sword for the bigger kids. Not brittle enough to break but not hard enough to hold an edge.

Just curious as to your opinion of it; I'd like to try my hand at a few tools and would hate to spend a lot of effort trying & failing to get a final temper only to discover my errors were actually made two or three steps back.

Spring steel is high carbon steel, if you bought new steel 01 or W1 would be much the same, it is easy to work( so they say). It can be quenched more than once if it does not work out the first time, other steels can not.
If you heat the steel untill a magnet does not stick to it and it is hot enough to quench, any more heat risks damage to the steel, lots of leeway here. The phone seems to ring just as the steel gets hot. Use a old speaker magnet.
It might be easier to heat treat it in the kitchen oven,pre heat and bake at 350 to 400 f for one hour depending on how soft you want the steel. Hard means stay sharp longer but breaks easier. Soft means needs sharpening more often but bend easier. If you clean the metal and bake it should turn a straw colour if you are in the right range. Start low and go up if you over heat it you have to go back and quench it again. If it turns purple you are getting out of the range. It is best to heat treat the steel as fast as possible after quenching.
I built a small forge out of two fire bricks, which you can get from a pottery supply store( kiln bricks). I cut out the center, wired them together and heat with a small propane torch( venturi style). The venturi burner is the big cost as the bricks are $7.00 a pair, where the burner might be $40.00.
Andy I think your system is super and do not be too hard on yourself. The cracks you get are probabaly in the leaf spring as micro cracks from its use as a spring and can not be detected, but hey if the price is right rock on.
Cheers Ron

Andy,
Did i miss a thread about your shaving horse? if you haven't done one yet, can you please? thanks

-Ryan

Hi Ryan,

I did post some shots a while back...try this: http://www.woodworkforums.ubeaut.com...ad.php?t=21633

Cheers,