recurve grinding magic...

S

SkaerE

Joined
Sep 9, 2001
Messages
428
ok, i figured i'd ask even before i started my first, but i just cant seem to picture in my mind how you go about grinding a recurve blade.

it seems to me that you would have to use a narrower belt for a small recurve (because a 2'' belt would hit all over the blade)

can you flat grind a recurve? is hollow grinding one easier?

i'm assuming you dont just move the blade across the belt on a perfect horizontal, there must be a good amount of movement to follow the recurve?

thanks, you fellas have always been helpful! :)
 
Hey, I did one some few knives back, a Persian, on a 1 X 30. I thought the same as you and wondered if the distal would grind okay. No problem. Just let it flow. Before you've got the plunge line fully cut you'll see there is not much mistery to it.

I did not have my 2 X 72 at that time and that is the only reason I ground it on a 1 inch belt.

P.S., I did it full-V flat grind.

Roger
 
I just did one too, same as Roger, full flat V grind. It wasn't too bad but I had a devil of a time getting it really flat because using a full 2 inch belt I had to use the edge of the belt mostly. I finally ended up sanding by hand for a couple of hours before finding a quicker way. I really went through my whole repertoire of tools and techniques but then something that Barry Jones mentioned awhile back came gushing up to the surface of my feverish brain................ Flat stones................. I'm thinking, what do I have that's a flat machinist stone that I could use to sand a hardened S30v folder blade? Gee, wouldn't DIAMOND be nice.......Hmmm, how about these extra DMT stones left over from making Prybabies? Boy Howdy, are they FAST! :) Don't know how long they will last but for now I am definitely liking it! :D

warlocks1.jpg
 
Hey Peter, that's real nice looking work. You got a better looking finish on that s30v than I have been able to do with it yet.

I may be wrong about terminology here. Perhaps the one I referenced is not considered a recurve. But to clarify, here it is: http://riflestocks.tripod.com/pics7.html

BTW, it is not damascus. Those are tree branches reflections. I should explain that because someone else thought I might be trying to pass it off as damascus.

Roger
 
Nice knife Roger but it ain't a recurve. The second blade above is a recurve shape, yours is an upswept Persian shape. The finish isn't bad but it isn't quite done yet either. I'm hoping to get it a little better than that for the final finish. You want to see a nice handrubbed finish on S30v, check out an Onion in person. Holy Smokes does he make a gorgeous knife! :eek:
 
I have a curve blade to do myself. I asked a mate he told me to split my 2 inch belt down the center to make it a 1 inch. He said track the belt to the sides of the wheel depending on which part I am grinding.

It sounded good at the time but I have still not tried it. To lazy too scared, not enough time. Pic an excuse I have used them all.
 
I wouldn't split the belt until trying it first as is. If you're going to lay it over the platen what makes the difference how wide the belt is?? , I wonder.

RL
 
I do quite a few flat ground recurved blades...
I just sort of ride the side of my platen in the curved area.. I use a 2x72 grinder.. Its hard to explain but it works fine once you get the hang of it...
 
I'm no expert by any means, but hollow-grinding one doesn't seem too bad. Just keep everything straight on the wheel and follow the curve of your blade.
 
The blade i was making is for a pruner it is only about 2 inch of cutting edge. I had a go on the first one and ended up filing it flat instead of hollow grinding. I may make a couple of wood blanks and have a practice to build my confidence. Sometimes a bit of confidence is half the problem.

I think the idea of switching the belt from side to side on the wheel was to put a shoulder on oposite sides of the blade as you grind left or right. Thanks for the advice guys I will try the 2 inch first. not for a few days yet too many other jobs.
 
Some consider it cheating, but I think it works well. Its what I do. The grindline doesn't have to follow the edge, does it ? I only flat grind and when I do recurves on my 2inch wide belt, I do it by keeping the grind line straight, but I rock the blade as I go towards the tip, so that the bevel is actually a different angle / thickness from ricasso to tip. At the ricasso, the bevel is broader and more obtuse, towards the tip it becomes thinner and a sharper angle. Ie.- the edge recurves, the grindline doesn't. I find this techniaque easier for me than "dancing" to sweep the blade this way and that when trying to follow the edge profile for the grindline.

Another idea - when hollowgrinding, if your hollow is quite deep, the steel thickness is quite similar in the lower 1/4 of the grind towards the edge. So you can grind a grindline that is meant for say an straight edged "hunter" and then when finsihed go back and grind away the edge to make the recurve shape and the edge thickness still won't be much thicker from one spot to the next.

Just my 2cents. Jason.
 
I grind my recurve knives on a 1 inch wide wheel,it solves alot of problems, if you are hollow grinding
 
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