How can I design a custom ergonomic knife handle?

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Steel_Magnet77

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Apr 10, 2025
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I guess I will take another stab at this. I can only make handles that are comfortable to my hand, and when I make a knife for someone else I am essentially guessing at what will be comfortable for them. My goal is to be able to sell knives with custom handles to fit the buyers hand in an ergonomic way. In order to do that I would need to create a process system that uses a couple measurements from the buyers hand to give me optimal handle length width and height. The overall shape and swells of the handle would be less relative and could simply be scaled. How can I design a custom ergonomic knife handle for the buyer?


p.s. Mildly sad that my other thread was killed. Not really sure why, maybe too scientific? But you can make anything scientific 🤣.
 
Steel_Magnet77 said:
I guess I will take another stab at this. I can only make handles that are comfortable to my hand, and when I make a knife for someone else I am essentially guessing at what will be comfortable for them. My goal is to be able to sell knives with custom handles to fit the buyers hand in an ergonomic way. In order to do that I would need to create a process system that uses a couple measurements from the buyers hand to give me optimal handle length width and height. The overall shape and swells of the handle would be less relative and could simply be scaled. How can I design a custom ergonomic knife handle for the buyer?


p.s. Mildly sad that my other thread was killed. Not really sure why, maybe too scientific? But you can make anything scientific 🤣.
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I was tempted to have more fun with this but I hate being shot at . . .

Isn't there some kind of medium like clay / putty / plastic that once shaped can be somewhat firmed up in a micro wave oven.
Your prospective customer could gently squeeze a handle like sample and then cure it and send it back to you and you could see how wide their fingers are and palm width and maybe some other things once you got used to looking at what is returned to you.
 
You're making a mistake here by presuming everyone will hold their knife the same way all the time. Different tasks mean different grips. You won't do fine cutting in a reverse grip but you might want that option if you're defending yourself.

You already got the answer, make them as neutral as possible. You can offer a couple sizes, a few materials and finger grooves or no grooves but no one is going to want a handle that's like wearing a glove.
 
Steel_Magnet77 said:
I guess I will take another stab at this. I can only make handles that are comfortable to my hand, and when I make a knife for someone else I am essentially guessing at what will be comfortable for them. My goal is to be able to sell knives with custom handles to fit the buyers hand in an ergonomic way. In order to do that I would need to create a process system that uses a couple measurements from the buyers hand to give me optimal handle length width and height. The overall shape and swells of the handle would be less relative and could simply be scaled. How can I design a custom ergonomic knife handle for the buyer?


p.s. Mildly sad that my other thread was killed. Not really sure why, maybe too scientific? But you can make anything scientific 🤣.
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Let's move this one to the Knife makers' area.
 
Width at knuckles might not be a bad idea as far as measuring goes.

I like non indexing handles so they just work but I get the idea.

I consider 4.5" a full sized handle on any knife, maybe 5+ for a chopper and 4" for a mid sized handle. This is just really ballpark though, too many things to consider.

System - 3D print templates with scales at different percentages and ratios. Send to customer for feedback.

As far as my opinion goes I don't really like the idea, lol but maybe it would work! Anything to improve the knives can't hurt. I see getting into all sorts of problems with this method though, to me it might be best just to make them to work for most people then offer different options.
 
You'll have to talk individually with each customer and get them to test the handle. Do an iterative process of adjustments
What's going to affect this is not just size and shape of the person's hand, but also strength of musculature, injuries like RSI, exactly how they use the knife and what they use it for. Basically once you start really measuring people everyone is unique.
You can optimise for all this to different degrees, depending on what you're trying to do. There is a lot of "good enough" area. But if you really want a great fit for a given person you need to talk to them and work with them to design it.

What i do, as someone who only really makes kitchen knives, is only make simple wa style handles. I talk with each person about how large their hands are and if they have any injuries and make broad adjustments in terms of handle size, and make further customisations if they need
People seem happy with this, although i think there's still a lot of space to get it really spot on
 
Wowbagger said:
I was tempted to have more fun with this but I hate being shot at . . .

Isn't there some kind of medium like clay / putty / plastic that once shaped can be somewhat firmed up in a micro wave oven.
Your prospective customer could gently squeeze a handle like sample and then cure it and send it back to you and you could see how wide their fingers are and palm width and maybe some other things once you got used to looking at what is returned to you.
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I suppose that would give me a limited view on what their hand dimensions would be. But in the end I hate any kind of finger grooves due to their extreme grip limitations... And there are probably easier ways to find palm measurements. Just my opinion.
 
Daniel Fairly Knives said:
As far as my opinion goes I don't really like the idea, lol but maybe it would work! Anything to improve the knives can't hurt. I see getting into all sorts of problems with this method though, to me it might be best just to make them to work for most people then offer different options.
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What kind of problems do you envision?
 
I think it's possible to overthink this kind of thing. For me, just shaping lots of handles provides the best feedback, it's a skill and as such is something that can be improved upon with repetition.

That said, probably the easiest way to design a handle for an individual is to get them to send you a tracing of their hand that shows where their finger joints are located. Compare the tracing to your own hand. There are a lot of bones in the hand and an infinite number of dimensions to account for, so this is a pretty simplistic method.

As someone else mentioned, the type of knife should instruct handle design in a more general sense than an individual's measurements. For example, a knife that will see a lot of 'camp' type work will need an oversized handle in order to prevent cramping and fatigue. Our hands change shape somewhat as we work with them- the soft tissues and tendons stretch out and contract as we do the things.

Ultimately, I think that the best way to learn how to design handles is to use the kind of knives you make as much as possible. That feedback is more instructive than anything else I can think of.
 
I finish a handle to 90%, then I lay it in the living room with a pencel and over the course of a week or two I pick it up, close my eyes and mark any spots I feel.
I finish the knife when I can't feel any spots anymore.
Time helps, a handle feels different if you let it rest a few days, your hand gets used to the shape. Pick it ip a few days later and it will feel different.
 
Welcome to Shop Talk, Steel Magnet 77. Fill out your profile so we know where you live and a bit about you.
You are a young knifemaker and it isn't uncommon to try and re-invent the wheel. However, there is no real need for a new shape of wheel.

The earlier thread was closed because it was going nowhere, and someone used a coarse terminology. The Moderator closed it before it got way off key.
You started this new thread in General Discussion right after the first was closed and the Moderator moved to Shop Talk. As you are seeing, the basic replies are much the same.

My comments:
There have been millions of knives made and sold that were made for the "average" hand. Some knives are bigger and work for larger hands. Some knives are smaller and work for smaller hands.
On the other hand, there are very few knives made for one specific hand .... except by the knifemaker for himself. Those knives rarely sell to others.
Unless the knife is made for a specific reason, like a user with m=no thumb or damaged/malformed hand, there is no need to come up with a "custom fit handle".

Don't overthink a knife.
1) The blade shapes used have been developed for centuries to do specific purposes.
2) The handles have been made in certain shapes and sizes for centuries. They fit 99.999% of the world's knife users. Those are the people who buy knives.
 
" What kind of problems do you envision?"

I could see making several knives for a fussy customer, and the customer not wanting any of them. What will you do with those knives then?

Seriously, I have made .... and sold ... at least 1000 knives, and the only requests for a special handle were maybe a dozen or so left-handed Japanese kitchen knives.
 
Stacy E. Apelt - Bladesmith said:
The earlier thread was closed because it was going nowhere, and someone used a coarse terminology. The Moderator closed it before it got way off key.
You started this new thread in General Discussion right after the first was closed and the Moderator moved to Shop Talk. As you are seeing, the basic replies are much the same.
Click to expand...
Thanks! That makes sense.
 
When I design a knife, in order to gauge handle comfort, I usually take the knife and grip it in my non-dominant hand.

I have used modeling clay to design an ergonomic handle shape in the past, using an existing blade and handle, applying clay and gripping it. Not so much to exactly replicate the shape in the clay, but to clearly see where gripping force is applied, and where hot spots may occur in extended use. This gives me a blue print to further refine the handle, but these are NOT custom fit to an individual hand, more a guideline on where to put inside curves, outside curves and palm swells.

In the end, doing that for every individual is not feasible.
 
It seems like I am getting a "Don't do that vibe" 😅. I was wondering the best way a knife maker can make an ergonomic handle for the customer. From what I am understanding from these replies, I should just make a lot of handles and use classic handle profiles and that will be good for the customer. I will say that I really don't want to reinvent the wheel. I just wonder if biomedical handle ideas could add to the comfort and ergonomics of a knife handle. I also realize that I could be in for a let down after I implement these shining scientific ideas and that it might not be any better than a classic shape XD. I was wanting to remove some of the guess work when I make a handle for a buyer.
 
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