How to determine and get correct balance point when designing and building a knife?

TK Steingass

TK Steingass

Troglodyte Knifemaker
Knifemaker / Craftsman / Service Provider
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Oct 16, 2010
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Fellow knifemakers:

Here's a sole authorship camp knife I just finished and gave to my son. 3/16" O-1, 6" flat ground blade with distal taper and convex edge, 10 3/4" OAL, gabon ebony s-bolsters, red lines on fiddleback walnut with black micara pins, extra fine scotch brite finish. My question is when you guys design a knife, how do you work the design so that you get the correct balance point? When building the knife, I didn't know whether to leave the tang full thickness, remove metal by skeletonizing the handle it or tapering it. I left the tang full thickness and I just got lucky with this one - it's at the index finger. Is this just a trial and error thing until you've refined a design by making many knives of a specific design but with different tang treatments? Or, are there any rules of thumb you guys use? Right now, I'm working in the dark until I get a design 100% completed - there has to be a better way.

TK

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Jack:

Thanks for the compliment. He sure did - trouble is he's a Navy Corpsman with the Marines in Okinawa. He's visiting with us on leave - he can't take it back with him because it's illegal by the local laws.

TK
 
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A nice knife indeed! Those shaped bolsters are very cool.

As for balance, it's kind of trial and error. Certainly you want the balance to be farther forward before putting the handle on, that can give you a ballpark idea. And dry-fitting the roughly-shaped handle will give you an even better clue.

I've found that the differences in tapered tangs, lightening holes etc are kind of subtle. Definitely there, but if a blade is really clunky to start with, you can only do so much with it. It's not like tapering the tang is going to shoot the balance point forward by an inch.
 
I would think that finding the right balance point would determined by the function of the knife. For a chopper, I make a very light handle with several holes and put as much metal near the tip as possible. For a fighter, I would think the balance needs to be near the middle.

Handle material will make a big difference in balance. Osage orange, for example is much heaver than redwood. Put a light wood on a fast knife. Just my .02
Jason
 
jawilder said:
I would think that finding the right balance point would determined by the function of the knife. For a chopper, I make a very light handle with several holes and put as much metal near the tip as possible. For a fighter, I would think the balance needs to be near the middle.

Handle material will make a big difference in balance. Osage orange, for example is much heaver than redwood. Put a light wood on a fast knife. Just my .02
Jason
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+1 on that! Puprose has a lot to do with the knife. Say a fighter or Bowie they would usually be blade heavy but, for a skinner the weight is more in the handle as the blade is needed to be guided and the handle has to do the guiding, and a food chopper is more of a balance act, leaning toward control of what will be a sligtly blade heavy knife. Hope that makes sense!
 
Where does the knife currently balance? I tend to disagree that a fighter should be blade heavy. In my opinion balance should be neutral, meaning on the forefinger. In fact, most knives except choppers benefit from light weight and neutral balance. But that's just me.

Great looking knife, btw. Tricky getting that bolster treatment you've done. I'm sure matching it side to side wasn't easy.
 
It's a great looking knife and very well made as well !!!
Here is how I do bolsters with curves and recurves. I finish the two pieces to 400 grit on the side to go on the blade. The other side I finish to 220 grit keeping these outside parallel to the sides that will fit against the blade. I drill the pin holding holes through one bolster, place the pins in place,and scribe the outline of the blade. I do the same for the other side. I now rough grind the outlines on both. I decide what shape the front and back edges of the bolsters will be and rough grind that shape on just one of bolsters, place the other one on top, and get it close. I use an inexpensive router and table with sanding drums with 1/4" shafts and slow speedto size and finish both the same together. My last step is to separate the two bolsters and go around the edges once more.
That knife looked so nice I couldn't resist wanting to tell others how to do matched bolsters. I do straight cut ones the same way. I hope TK understands. Frank
 
I'm with Jerry!!! I personally want a person to pick up one of my knives and be surprised that it feels like a feather... Even if it has an 11" blade.

There are times when heavier is better.... say a chopper that's going to cut down trees or a bowie/fighter that needs some "knockdown power" Joe Paranee style!!! ;) :D

But 98.7% of the time I go for a neutral balance, just like Jerry wrote about. :)
 
Frank Niro said:
It's a great looking knife and very well made as well !!!
Here is how I do bolsters with curves and recurves. I finish the two pieces to 400 grit on the side to go on the blade. The other side I finish to 220 grit keeping these outside parallel to the sides that will fit against the blade. I drill the pin holding holes through one bolster, place the pins in place,and scribe the outline of the blade. I do the same for the other side. I now rough grind the outlines on both. I decide what shape the front and back edges of the bolsters will be and rough grind that shape on just one of bolsters, place the other one on top, and get it close. I use an inexpensive router and table with sanding drums with 1/4" shafts and slow speedto size and finish both the same together. My last step is to separate the two bolsters and go around the edges once more.
That knife looked so nice I couldn't resist wanting to tell others how to do matched bolsters. I do straight cut ones the same way. I hope TK understands. Frank
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Frank: No problem at all on my end when it comes to sharing knowledge and experience!! Before I got into knifemaking I was a stockmaker, so figuring out how to make a matched set of intricate bolsters then installing them for correct alignment was no big deal. I minimize the risk of different sizes by doing all machining and drilling of the bolsters while they're taped together with plain old scotch tape. Then I separate them and use one of the bolsters as a template to mark the holes in the blade - I only drill in a little bit to start the indentation, then remove the bolster to prevent heat damage. You can't screw it up this way - you always get perfect bolster alignment on the blade.

TK
 
NickWheeler said:
I'm with Jerry!!! I personally want a person to pick up one of my knives and be surprised that it feels like a feather... Even if it has an 11" blade.
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I agree, too. It's pleasantly surprising how lively and quick even a large, very powerful knife can be if well-designed and well-balanced. Of course it kind of spoils you for most of the sharpened pry-bars coming out of factories. ;)
 
Jerry Hossom said:
Where does the knife currently balance? I tend to disagree that a fighter should be blade heavy. In my opinion balance should be neutral, meaning on the forefinger. In fact, most knives except choppers benefit from light weight and neutral balance. But that's just me.

Great looking knife, btw. Tricky getting that bolster treatment you've done. I'm sure matching it side to side wasn't easy.
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Jerry: The knife balances on the forefinger - I got lucky with this knife. I agree with you - I like a knife that's light in the hand - my buschcrafters differ from the traditional full thickness tang bushcrafters because it's used as a chopper. Here's one of my sole authorship O-1 bushcrafters and hunters- light as a feather in the hand but they didn't sell worth a damn, even after splitting up the set and lowering the price from $225 to $150 per knife! I couldn't believe it. Maybe they would have sold at my price if I had made leather sheaths and had name recognition, like a J. Nielson. I ended up giving them away to two very surprised and appreciative friends - I imagine I could have gotten $100 apiece for them but it was worth more to me to see the expression on their faces!

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In my opinion, the whole exercise gets a lot easier if you don't use thick steel. We have great steels today; there's no reason for them to be thick. Besides, it makes no sense to use thick steel to start with if your grind makes it thin near the point. The point is what's going to break first. I've seen blades that were 1/4" thick at the guard and 1/16" thick two inches from the point. I've found with that a diligent effort to remove as much weight as possible from the knife, balancing can become a non-issue. Why? Dunno, it just does. All of my knives with blades up to 8"+ balance on the forefinger. I make no effort to cause that to happen. They balance; I'm clueless. There you have it. Confessions of a knifemaker. :D

And yes, it's fun to watch someone pick up a large knife and be surprised. I've often been asked, "what's it made of." The whole issue is weight and balance together. If it balances it will naturally feel lighter. If it's light AND balanced, people are just amazed.

Nick, I disagree. I think it's more like 96.4%. :D
 
Wheeler's Steel is a perfect example of what Nick and Jerry are talking about. Looking at it, you'd think it was heavy, but you pick it up and it's like 15oz, (that's 2 1/2 - 3 tactical folders worth of weight) but the blade is so long somewhere around 11". It balances somewhere in the ricasso area.

If a knife isn't light, then it's too heavy. Relatively speaking, of course. Remove weight wherever possible, without compromising strength or functionality, and you'll have a knife with balance.
 
More good points above. We are blessed with some pretty amazing steels today, very tough and with excellent edge-holding. We can grind our edges thin so they slice, cut and chop really well but are still rugged enough for a survival or combat knife. At no other time have so many options been at our disposal to make fast, comfortable, powerful knives that are reliable and low-maintenance. It's a great time to be a knifemaker; I daresay we're in a Golden Age of available materials techniques and information.

However, I must confess I occasionally like to make a real whopper chopper out of thick stock just because I can :D
 
From other applications , wouldn't you be able to do a formula to find the C of G ( Center of Gravity) then remove weight from say the tang to have it balance where you want. I might be way out in left field on this one . Or when designing the blade work out the C of G and adjust your blade to balance it where you want it . I'd keep with the experienced guys response but it's just a thought.
 
Plus Jerry would have to figure it out for knives with handles shaped like this:

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Give the guy a break! :D
 
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