Thursday, 29 September 2011

How to handle a drawknife and other tanged tools

To follow on from the post on how I sharpen drawknivies. Here is how to put new handles on it. I will assume that either you have handles, or can turn new handles, either on a pole lathe or a modern electric lathe. If turning on a pole lathe either turn green, dry the handles, and then turn again when dry to fit the ferules, or turn from seasoned wood. I often turn dry wood on the pole lathe if I want round turnings. If possible use the original ferules or use new ones or cut some from brass or copper pipe. The ferules will need to be put onto seasoned wood, we do not want the wood to shrink and the ferules to become loose. This is a C Whitehouse drawknife, and I turned the the handles to the same pattern as the originals.
I use long series drill bits and I drill in from each end rather than drilling all the way through. This way you will get the entry and exit holes in the right place. This process is not easy, so practise on odd bits of wood to hone your technique.
If necessary drill a larger hole part way through if the the tang is thick at the blade end. The old handles are split off using an old chisel.
I am lucky that the tangs are in reasonable condition. This one had a bit of rust and is slightly thin in the middle, but will work well enough. Sometimes you will need a new tang welded on. Unless you can do this yourself, find a friendly blacksmith or fabricator to do this for you.
 Make the tang straight by heating it with a blow torch. Make sure that the blade section does not get to hot as making the blade too hot can change the temper or hardness of the steel. Note that I have the blade on my anvil, which acts as a heat sink for the blade.
Make each tang straight and in line with each other.
Heat the tang up again and push the handle onto the red hot tang.

Do not push the handle all the way onto the tang, leave enough so you can hammer the handle firmly onto the tang. Pull the handle off as soon as you have got far enough down the tang. It is best to let the tangs cool down slowly as quenching in water can harden the tang and make it brittle.
When the drawknife is cool to the touch, paint linseed oil onto the tangs and inside the burnt hole. Using a scrap bit of wood with a hole drilled into it, bang the handle fully down into place.
I made a washer from a bit of brass, and if the tang sticks out a bit to far just file or cut the excess off. You only want 2 to 3mm protuding above the washer.
Using a ballpein hammer, mushroom over the tang. Do this hammering the tangs outer edge around in a circle, do not hit the tang square on in the centre.
The finished  handle.
Bevel up
Bevel down
With a wooden mask for the blade.

I use the same general principles for putting handles onto chisels.