First demonstration of the year at Yandles Spring show this Friday and Saturday. I am amazed at how far I have come, this show last year was the first time I had forged an axe in front of a crowd, it took the entire day, hopefully we should be a bit more fluent this weekend! I have made a few tweaks that should help things along further:
Firstly I have been trialling a different sledge hammer design, virtually everyone that has used my larger sledges has ended up with bruised hands, it puzzled me at first as I have never encountered bruising when using single handed hammers. Working by myself I have had very little experience with sledges; eventually it struck me that mostly my strikers were holding the sledge with their hands far apart:
This is understandable, the hammer is heavy and there is more control and accuracy when holding like this; however when a (single) hand hammer rebounds the head goes up but the centre of rotation is in the palm of the hand so little shock is transmitted to the hand through the handle. With the hold shown above the the centre of rotation is between both hands, so when the head rebounds the hand nearest the head receives a big shock from the handle in the web between thumb and forefinger. The back hand doesn’t suffer in the same way as the handle is moving away from the hand at this point.
If you look at the new sledge, the handle is so short that it feels more natural to have both hands together, the centre of rotation is between both hands, but as they are so close to this point the shock is reduced to almost nothing. It looks odd but has worked well in the workshop. However I think it will look a bit like a toy in the hands of Rob, my regular striker at shows, I will find out his verdict in a couple of days! This is of course a compromise, the bigger sledges will hit harder but really need to be held with hands together to reduce the shock, with practice this is possible but it is difficult to do this accurately, when I am teaching courses the shorter style of hammer looks to be the way forward.
The second thing I have done is to reduce the height of my anvil block, in the workshop during courses I have been putting a pallet down but it seemed sensible to have a dedicated axe forging block. I moved both of the steel bands down and we marked out for the cut. The Oak had many splits in it that had filled with forge scale over the last decade, the chainsaw was blunted in seconds but we eventually managed to cut around 4″ off it. I used a chisel I made around 15 years ago to bevel the edges on the block; the edge held very well considering the rough time it had. This set me thinking, with the knowledge I have now all the heat treatment was wrong; the blade was laminated but I didn’t follow the rigorous thermal cycling I now use to relax the steel after the stresses of forgewelding, I quenched at the wrong temperature, too cool, although this was judged by eye, the quench medium was wrong, water rather than oil and finally I tempered at the wrong temperature 100 degrees centigrade, boilling water. I have heard it stated that this steel should be tempered at 250c when used on wood.
Yet despite all this the edge holds up well; this wasn’t all just accident I had found by trail and error that this recipe worked . What I think happened was this: As I was relatively inexperienced at forging I finished the blade relatively tentatively at a series of low heats, this mimicked the thermal cycling that I now do. I had the hardening temperature too low, but quenching in water gives a more aggressive quench so this sort of balanced out, if I had quenched in water at the correct temperature the blade would have cracked or at least warped. The resulting quench didn’t give a very hard blade so lower tempering temperature was needed. I would still do things differently now but you can learn a lot more from trial and error, I would recommend this route rather than reading up obsessively on Heat Treatment.
Just after taking this photo I was asked to run a course making spoon blades with handtools and no complicated heat treatment, not my usual thing but I made one as a test piece; this was the result, everything done by eye or hand and I managed to replicate the edge geometry that I find so important in my production blades. It was a pleasant experience, filing and forging is much more rewarding than grinding.