Tip Geometry

H

Hesparus

Joined
Oct 31, 2004
Messages
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I realize that the answer to this question depends a great deal on what the knife will be used for, but please bear with me.
I always see a lot of knives with really delicate tips, sometimes big knives with delicate tips. The few of knives that I have made with delicate tips are on the small side. Even on the little knives of mine, I am concerned about the tips breaking. When I grind any knife, I keep the bevel the same angle all the way up. When making a big knife with a delicate tip (like a lot of Bill Moran's knives that I've seen) is it common to grind the bevel at an increasingly wide angle as you approach the tip, or does one rely on the flexibility of the metal to take care of it?
I kind of feel like I've answered my own question, but I'd just like some validation and input.

Thanks,
Chris
 
The tip's job is to get the blade into its work. A fine delicate tip is one you can not count on when you want a knife to do serious work. I like to see the top profile of the tip look like a chisel. The sides of the tip completed this way will push the material away from the absolute tip and save it for the next job.
 
Tip geometry is a trade off. The thinner the distal taper the sharper the tip. The more abrupt the grind at the tip the more rugged it will be , like an ax compared to a letter opener. Knife making is all about trade offs. That is why there are so many different types and designs. Just my view, Fred
 
For a knife that will see rougher use, I do like to reinforce the tip a bit. For the most part, penetration is limited by the widest dimension, while strength is limited by the thinnest dimension. By keeping just a little bit of extra material at the tip, you make it many times stronger, without giving up hardly any penetration. (but maybe a little cutting performance if you go too steep with the angle at the very edge)

Examples:
My great uncle's Japanese swords both get greatly reinforced at the tip.
A while back I got to handle an art dagger, that had illogical grinds. The thing was ground from stock at least 3/8" thick and rather narrow, so it was more like a big nail. But the tip tapered down very thin, and it looked like 1/4" of it would snap off the first time it struck something hard.
 
As Ed said the Tip is designed to penetrate first and foremost.
Thats what tips do:D
Tip geometry needs to be ground for the purpose of the knife.
Just finished a Tanto (See Avatar) with an Convex ground tip...Needle sharp and strong as heck. Design is to survive penetrating hard objects...like some people's skulls.
 
The Sykes-Fairburne "light duty" combat knife is a good example - the tip often broke off ! For those who hunt pigs with a knife , they know the importance of a good knife.
 
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