Post by mikeinsjc on Mar 12, 2013 20:36:02 GMT -5
I have bent my share of blades, all 18". The last two have been particularly painful, as they were an original made in US Covington, and the next a nearly-new MK303.
I chatted with the MK guy, wondering if there was any fix for a bent blade. The short answer-no. The problem is that in order to straighten the blade they must be re-annealed. That in itself wouldn't be a problem except that the diamond is laser-soldered to the blade and that solder would melt out at the temperatures required for annealing. At least that is what I was told.
Nevertheless I cannot make myself part with a blade that looks nearly new. Someday, when I get bored, I am going to try my hand at straightening these puppies. I'm sure I will become a millionaire after I perfect the process.
Remember the old Rock and Gem mags showing a picture of some old codger bent over a blade with a hammer and block of wood? There's got to be a better way.
I have an old Frantom flat lap that I am converting to a 24" size. So here's what I am thinking. I am going to get a 24" plate Blanchard ground (probably not necessary, but I like the way steel looks coming off the grinder). I will then set up the plate on the lap and put my dial indicator on it and carefully map out the highs and lows. Maybe coat the blade with Dykem and set up a scribe to precisely map out the irregularities. I am just shooting from the hip on this, so if you have any ideas, please post them.
Straightening the blade- gotta be a more hi-tech method. I need to be able to apply a considerable amount of force smoothly to a small area of the blade. Hydraulics, maybe? The problem is the springiness of the steel. You will have to bend the blade past true in order for it to return to near-true. That part would probably be trial and error. I doubt the blade would ever cut like a new one, but it might work to save them.
What would be an acceptable runout for a blade? I have heard 0.015 is tolerable in a new blade, but have never put a dial indicator on a new blade to see how the come from the factory. Has anyone done this?
A final thought. When buying a blade, it makes sense to buy the thickest blade you can find. I have seen thin blades marketed with the less-material-loss-cutting-expensive-stuff mantra, but that seems risky when you are dealing with a $350 blade. Doesn't seem worth the risk. I want the thickest blade I can get simply because it would offer the greatest resistance to bending. Any thoughts on that?
I chatted with the MK guy, wondering if there was any fix for a bent blade. The short answer-no. The problem is that in order to straighten the blade they must be re-annealed. That in itself wouldn't be a problem except that the diamond is laser-soldered to the blade and that solder would melt out at the temperatures required for annealing. At least that is what I was told.
Nevertheless I cannot make myself part with a blade that looks nearly new. Someday, when I get bored, I am going to try my hand at straightening these puppies. I'm sure I will become a millionaire after I perfect the process.
Remember the old Rock and Gem mags showing a picture of some old codger bent over a blade with a hammer and block of wood? There's got to be a better way.
I have an old Frantom flat lap that I am converting to a 24" size. So here's what I am thinking. I am going to get a 24" plate Blanchard ground (probably not necessary, but I like the way steel looks coming off the grinder). I will then set up the plate on the lap and put my dial indicator on it and carefully map out the highs and lows. Maybe coat the blade with Dykem and set up a scribe to precisely map out the irregularities. I am just shooting from the hip on this, so if you have any ideas, please post them.
Straightening the blade- gotta be a more hi-tech method. I need to be able to apply a considerable amount of force smoothly to a small area of the blade. Hydraulics, maybe? The problem is the springiness of the steel. You will have to bend the blade past true in order for it to return to near-true. That part would probably be trial and error. I doubt the blade would ever cut like a new one, but it might work to save them.
What would be an acceptable runout for a blade? I have heard 0.015 is tolerable in a new blade, but have never put a dial indicator on a new blade to see how the come from the factory. Has anyone done this?
A final thought. When buying a blade, it makes sense to buy the thickest blade you can find. I have seen thin blades marketed with the less-material-loss-cutting-expensive-stuff mantra, but that seems risky when you are dealing with a $350 blade. Doesn't seem worth the risk. I want the thickest blade I can get simply because it would offer the greatest resistance to bending. Any thoughts on that?