It would be more accurate to say that I didn't temper my tools properly in the first place. This winter I am keen to make good use of my hook tools and so last Sunday I took time off from my planking project and went over to the forge at the Tilford Rural Life Museum.The musuem is between Farnham and Haslemere. It may seem strange for Surrey to have a rural life centre but its well worth a visit for its extensive collections of tools and rural items. (Tilford Rural Life Museum ) They have a great collection of Moss edge tools (local blacksmiths and much prized items). They even have a big wheel lathe there that I have been told is useable. The collection was started by one of the founders of the Tilhill forestry company, which I assume started life on a hill in nearby Tilford. It would have been open heathland until Tilhill started - I hear that the original Tilhill plantation is now an RSPB reserve and being returned to heathland again.
Hook tools are often used by pole lathe turners for bowls and is one area where pole lathe and power lathe turners differ in the tools they use. The photo shows the first hook tools that I made a year ago for small items such as goblets and egg cups. I made a batch and one is really suited to goblets but its been hard work as I failed to get the temper of the tool right and its been losing its edge really quickly.
John and Nick are the blacksmiths who work from the forge at Tilford and John helped me to improve the temper on my hook tools. Sorry about the rotten photos John.
Edge tools are tempered by heating the edge to a specific heat and then quenching (or cooling) rapidly to 'freeze' the metal orientation at that temper. You can do this scientifically in an oven by setting the temperature, or it can be done as originally by buffing the metal to a dull shine and then watching the colour of the metal closely.
John decided to retemper the tool by heating it in the forge until it was bright orange or dull yellow and then quenching just the hooked tip. This allows the heat in the thicker stem to flow back into the hooked tip and you can see the colours of the tip turn. After some tests we decided to temper to straw just before the very tip turned blue. As the tip turned clearly straw and just before it turned to blue John then quenched the whole tool. Comparing filing of the edge before and after retempering the tool is harder than before. During the last week I've been using the tool and my impression is that it's sharper and keeps its edge much longer - but sometimes all it needs is a good feeling, so its not an objective measurement.
It was also a Landrover day at the Museum so I got to park inside for a change. Here is a row of Series II Landrovers drawn up for inspection - most look immaculate, The tatty one at the other end is mine. Next year I am hoping for a prize for tattiest Landrover so I can win!
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