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Convex grinding?


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The ultimate solution is the rotary platen from KMG, but lacking the $473 or so that would set me back I just use a really tight slack belt and follow up with a LOT of hand sanding with a rubber backing. ;)

 

http://beaumontmetalworks.com/rotaryplaten.html

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I have this set up from KMG. It is really very good as you can choose a distance between wheel and a tightness of the rubber band that will give you the curve you want. IYt is very good for defining the final edge geometry on long blades like swords.

 

It does not remove the need for hand finishing, however. Even with this tool on my grinder I still spend hours hand finishing. Perhaps not as many as I would otherwise, but the tool does not replace the hand.

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I got one of the rotary platens too, it's a godsend. Seems like belts last longer on it too. Before I got it, I make a series of angles on the flat platen, then used the slack part of the grinder to smooth out the transistions. Seemed to work pretty good.

Steel is my canvas, a hammer my brush.

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the easiest way to do a convex grind is to first define the blade geometry by making many small hollow grinds. At first it is a little tricky but after a while this step goes very quickly. After the geomitry is set then go to the slack belt area of your grinder and blend all the ridges and hollows together to get a smooth convex. If you press too hard here you will round the spine and edge too much. I do the privious steps with a 36 and 60 grit belt. When I am happy I then move up in grits ending with an x16 norax belt. after this polish/buff then etch and polish again. you're done. A rotary platen makes the blending and polishing a little easier but in no way is it neccessary to get a good convex shape.

Bill Burke

ABS Master Smith

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the easiest way to do a convex grind is to first define the blade geometry by making many small hollow grinds. At first it is a little tricky but after a while this step goes very quickly. After the geomitry is set then go to the slack belt area of your grinder and blend all the ridges and hollows together to get a smooth convex. If you press too hard here you will round the spine and edge too much. I do the privious steps with a 36 and 60 grit belt. When I am happy I then move up in grits ending with an x16 norax belt. after this polish/buff then etch and polish again. you're done. A rotary platen makes the blending and polishing a little easier but in no way is it neccessary to get a good convex shape.

 

I'm sure I read that technique of making lots of hollows in a book somewhere. That's the first time I'm heard anyone mention it since.

 

I guess making hollows will make you belts last longer too with the grit opening up on the wheel.

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