12-20-2017, 01:39 PM
(12-19-2017, 10:11 AM)EOU Wrote: Our apologies Me2 for bouncing in and seizing on just a couple of sentences from one of your posts again but you have plucked a string once more on a subject we've been curious about for some time. " I used to sharpen a lot on a belt sander, but after years of thinking it was working fine, I found out my edges were being softened considerably, so I stopped for the most part. " It's not difficult at all to create a little warmth in the body of the blade while using many powered sharpening methods . Better sharpeners than us would tell you that they create no thermal transfer of heat from the edge to the bulk of the blade but still we wonder. Just how hot does the bevel and the tiny sliver of metal at the very apex of the edge have to get before it can transfer enough heat to warm a substantial portion of the entire blade even a very imperceptible 1 degree? We don't expect an answer to that question here. We certainly can't answer it. It's just food for thought. We don't hope or plan to derail the topic of this thread but Me2's observation and statement gave life to our question and as every Bladesmith knows "you gotta strike while the iron is hot".
The statement about the edges being softened by the belt grinder struck me. Recently I have been spending a lot of time converting a Viel and a Kally to variable speed. With the Viel, I also converted it to a smaller drive pulley, thereby decreasing the surface feet per minute even further. With careful technique, this should solve the overheating/softening issue. With variable speed and a coarse belt, the initial roughing could be done at a faster speed, slowing to cooler grinding as the blade stock became thinner.
Ken