Tri Hoang
06-03-2009, 5:26 PM
Following up on my question on how to grind a curve into my scrub plane blade, I got a few advices on doing it free hand. I tried it on a cheap blade and it turned out well and easier than I thought.
I've always wanted to camber my blades but have not figure out how to do it free hand. So a thought came to me that perhaps the key to cambering my blades is in the grinding, not honing process. I've seen David C. and Chriz S. video/article on cambering but I did not have much luck with the counting method free hand.
So I took out the blade from my jack plane to try it out. I did not draw a curve and try grind to it as many did because I could not find one that fit what I wanted. So I drew a straight line across the back with the appropriate amount of camber from the edge. I then adjusted the tool rest to 25* and proceed by keeping 50% of the blade (left) on the right part of the wheel and moving the front edge in an arc with respect the the grinding wheel while trying to keep the blade center. It's easier than it sounds. Once it's in rough shape, I switched side and did the right 50%. Once done, I center the blade and swing it in an arc with light pressure. This is the part when I adjusted for any imperfection in the camber. I hope the rudimentary illustration clarifies the process.
It's amazing how well the eyes can tell the slightest asymmetry in the blade by comparing the edge with the straight line. I check the blade every 30 seconds or so and adjust the swing of the arc to compensate of any imperfection. Total time: ~10 minutes. The camber is perfect. It takes time but it's certainly doable on a slow speed wet grinder (Tormek clone). Best of all, I did not have to shell out $100 for the new Jet cambering jig.
Once I got the camber in the shape I wanted, honing it free hand is easy. Carried away with excitement...I took out the blade on my try plane and put a 1/32" camber on it. Also perfect in about the same amount of time. Getting greedy, I added the camber to my LV LA jack blade (about 1/32")...also perfect.
So...for those who have trouble locating the right curve for the camber (too big of a radius needed...) just do it free hand. It's easier than one might think.
I've always wanted to camber my blades but have not figure out how to do it free hand. So a thought came to me that perhaps the key to cambering my blades is in the grinding, not honing process. I've seen David C. and Chriz S. video/article on cambering but I did not have much luck with the counting method free hand.
So I took out the blade from my jack plane to try it out. I did not draw a curve and try grind to it as many did because I could not find one that fit what I wanted. So I drew a straight line across the back with the appropriate amount of camber from the edge. I then adjusted the tool rest to 25* and proceed by keeping 50% of the blade (left) on the right part of the wheel and moving the front edge in an arc with respect the the grinding wheel while trying to keep the blade center. It's easier than it sounds. Once it's in rough shape, I switched side and did the right 50%. Once done, I center the blade and swing it in an arc with light pressure. This is the part when I adjusted for any imperfection in the camber. I hope the rudimentary illustration clarifies the process.
It's amazing how well the eyes can tell the slightest asymmetry in the blade by comparing the edge with the straight line. I check the blade every 30 seconds or so and adjust the swing of the arc to compensate of any imperfection. Total time: ~10 minutes. The camber is perfect. It takes time but it's certainly doable on a slow speed wet grinder (Tormek clone). Best of all, I did not have to shell out $100 for the new Jet cambering jig.
Once I got the camber in the shape I wanted, honing it free hand is easy. Carried away with excitement...I took out the blade on my try plane and put a 1/32" camber on it. Also perfect in about the same amount of time. Getting greedy, I added the camber to my LV LA jack blade (about 1/32")...also perfect.
So...for those who have trouble locating the right curve for the camber (too big of a radius needed...) just do it free hand. It's easier than one might think.