Design critique please and balance questions.

LiamLynch

LiamLynch

Well-Known Member
Here are two designs ive come up with, ignore the blue one. The large one is going to be 5mm O1 and the small 3mm both with micarta handles and 304 SS fittings. I'm going to rust blue or hot caustic blue them. The Khukri has a 10"ish blade. Firstly what do you guys think and secondly what can I do to make the big one not so blade heavy? Thanks guys. http://imageshack.us/photo/my-images/715/imagezgum.jpgimage.jpg
 
The trick to getting balance/"feel" on those knives will be paying close attention to the distal tapers, and making sure you hang too much material on them for bolsters. I suppose it all comes down to what an individual values more......looks, or balance/feel. Taking the grinds further up the blade will make the knife "lighter" and "faster", but if you hang a lot of hardware (big bolsters) on the handle end, they will likely feel somewhat "clubby". On the big knife, you will actually increase the strength and balance by putting in a full distal taper on the blade, and taking the grinds to nearly the spine. Often times the though pattern is that the more "meat" we leave on a blade, the stronger it will be.....not necessarily so.....you can increase strength by combining distal tapers with full grinds (to the spine) versus a knife with short grinds (as in the pics) and full thickness blades.
 
I'm not quite sure what a distal taper is but the grinds in the picture can really be higher than that because of what grinder I have. I am limited to what an inexperienced maker can do on a cheapy Clarke 6" grinder with a belt attachment.
 
The Kukri history is said to go back to when Alexander the Great invade northern India and the Copis design sword many of the greek/Macedonian soldiers carried. The Indian blade smiths made a smaller version for hand to hand combat that could be belt carried but smaller that the Copis sword.

This design is suppose to be blade heavy. Giving it massive hacking power in a over the shoulder and down at a angle to cleave into the neck shoulder area etc.

If you want to lighten it for a show knife that's fine. But it won't work as well. They say a warrior can decapitate a Water buffalo or cow with a single stoke due to this design.

A distal taper is why the tip of the knife is thinner that where the spine meets the handle. It takes practice,
But Ed is correct in that being on of the most important factors in lightening up a knife.

Good Luck!

Laurence

www.rhinoknives.com
 
Both Ed and Laurence are correct. What it comes down to is what you want the blade to do. If you want a heavy duty chopper with plenty of blade presence then you want more steel up front. A duel taper might even be in order. A proximal taper from the middle of the downward slanting section of the blade to the handle and a distal taper from that same point to the tip. I would not make either taper very pronounced, especially the proximal taper. If you want it to feel light and responsive in the hand then I would do a distal taper from the handle to the tip. You could even split the difference by having no taper out to the bend in the blade and then do a distal taper from that point to the tip. Each of the methods will effect the handling of the blade.

Doug
 
Liam, if you are going to make blades you are going to have to learn how to do tapers. They greatly effect the balance of the knife. A distal taper is from some some point on the blade, usually the ricasso or where the handle stops towards one end of the knife. Towards the point is almost always done. There are few knives where you want the blade to be of constant thickness from the handle to just before the point. It's a little hard not to put a bit of a taper there. You can also have a taper in a full tang knife from that point to the end of the tang. That helps distribute any side ways stress in the knife better and also helps shift the weight of the handle forward. I wouldn't do it with a hidden tang.

A proximal taper is from some point on the blade back to the handle. One pattern is that this is frequently seen on is the broken back seax when it has been forged. Driving the steel into itself to forge the lateral taper from the spine to the point makes the steel thicker there. The final form of the blade will be thickest there and the blade is tapered from there both towards the the tip and the handle. It's just something that comes "naturally" with that pattern and some knifesmiths who make that pattern of knife feel that is should be there, though it can be forge out. It's easier to set tapers on an anvil but it can be done with a grinder too. Where and to what degree are going to depend on the usage of the blade; the old form follows function rule.

Doug
 
QUESTION say id like a lighter / but heavy use (The Khukri has a 10"ish blade.) as LiamLynch said. what kind of distal tapers, proximal taper im thinking a camp knife with balance but not over heavy no bolsters. ALSO im a hand tool novist ive make some kneck knifes & skinners so far??
 
You're looking a bit at opposing characteristics here so there is going to have to be a compromise. For balance you will have to decide if you want it to be balanced to be responsive in your hand, which may put less force in the blow from the blade, or to have it balanced for the chop, which will give it a blade presence and be less agile.

In the first case I would do a slight distal from handle to point, especially if you are not putting any furniture one the blade. In the second case I would do a distal taper from the sweet spot to the point and a proximal taper from the sweet spot to the handle. Steel selection will important too. I would go for one that has good toughness over strength and wear resistance, maybe 5160 or 9260. Maybe even 4140, though that's a little low in carbon, the molybdenum and increased ferrite, if you do a differential hardening, will add to the toughness. I'm sure that there are people more experienced with steel selection who could give more informed advice.

A convex grind would also put more strength behind the edge.

Doug
 
I want it to be fast in the hand, either way it will be good at chopping. I can only get O1 and only have the tools for saber grinds at the moment. I will try at a proximal taper but I really don't like the idea of the thinnest part being at the smallest section of blade so proximal taper is off. I don't really know what you mean by furniture on the blade though.
 
Furniture means things like guards, bolsters, ferrels, and pommels. Being generally made of metal they can add weight to the handle and bring the point of balance back.

Doug
 
I'm going to be doing big bolsters I think will 304 be heavy enough to counter out a heavy blade. I have made a 10" Bowie before but it has no bolsters so its very blade heavy. It is slow in the hand but it is easy to handle. I don't really know what well balanced feels like, I assume I will know it when I feel it though.
 
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