Making a small CNC knife batch project

daizee

daizee

Knifemaker / Craftsman / Service Provider
Joined
Dec 30, 2009
Messages
11,153
Hi Makers,

I'm cautiously embarking on a new "knife-making" project that is quite a bit more ambitious than my last attempt (chronicled here in this forum) a year ago, and need some helpful advice from those with experience. My first, and thus far only, knife-making project a year ago taught me a LOT about what it takes to make a knife. Chiefly how difficult it is! It became quite clear that I don't have the tools or skills to do the job by hand.

I have a knife design which I would like to prototype by contracting out much or all of the work to a CNC shop.

I have a bunch of CAD models which are little more than drawings IN a CAD program. I'll need to clean those up into something a shop can use.

The current plan is:

1) have a fab shop with a waterjet machine cut out the carbon steel blanks. If possible, I'd like the same shop to put the primary grind on the blanks to reduce the number of steps.
1.5) possibly have the same shop cut out the scales as well (wood or micarta)
2) Send the blanks to another shop for heat-treat
3) Edge them at home?
4) Finish the handle scales and install
5) Send out a sample or two to have kydex sheaths made.

I plan to hex-bolt the handles on with probably 3/16" shank bolts with a 1/4" or so counter sink. I haven't selected hardware yet and thus haven't confirmed the sizes for sure. This will let me swap materials and colors until I'm happy.

Scales could also be cut at home if necessary.

I'm going to try to keep all the work local as the economy here sucks and I'd like to help. I expect to have a small budget for the project in the new year.

Does anyone have an gotchas I should watch out for?
Is a fab shop likely to be able to do the primary grind as well as the blank?

I've had a couple very early conversations which got me focused on creating a CAD model, but not much more than that. I plan to have a batch made to keep the cost per knife reasonable, and hopefully sell off the extras, give them as gifts, trade, or whatever seems appropriate.

Thanks for your input,

-Daizee
 
I agree with the above statement. Not many shops can put a bevel on a blade. Reason is it takes custom made tooling, IE a carbide 12 deg cutter that can cost $800.00 or more. Most machine shops dont have cutters like that sitting around. If you want to keep the job local you really need to be talking to the machine shop foreman and show him your prototype and see how he thinks it can be done.
Chris
 
I disagree with Chris a little here, no custom made or special cutting tooling is required.

Just some ingenuity and skill.

I cut most of my bevels on the mill before I go to the grinder, and haven't had to spend more than $40 on a carbide endmill yet.

Still, you need to talk to your local shops.

Many shops would not be able to figure out a way to cut a traditional bevel without scallops, fewer still can grind a bevel.
 
While there is many ways to put a bevel on a blade. I personally use a ball end mill bit and keller them in my workshop. Llink below of the last knife I CNC'd.
http://www.bladeforums.com/forums/showthread.php?t=781911

I write my own code and did a run of 20 knives in the above thread.
Upside is ball end carbide bit costs $25 downside is the time it took to do the job. Since I did not have to pay a shop for their machine time it cost me nothing but my time. If you are doing a manufacturing run you do not want to machine bevels in this way. Remember time is money in a machine shop.
But if someone wanted me to do a production run I would personally want a 2 or 3 inch 11 or 12 degree carbide cutter to do the job efficiently. And you aint getting a cutter like that cheaply.
Chris
 
Very helpful feedback, guys.

Perhaps I should plan to invest in the benchtop tool necessary to do the primary grind by hand. My time and skills are short, but I can probably manage that grind as opposed to shaping the entire knife. The more shops involved the more expensive this project will get.

-Daizee
 
Hahaha, I don't doubt that I could shape - but shaping the same way every time?
I'm sure doing the bevel consistently is no easy trick either, but the less repetative precision required from my hands the better.

Do you think it would be cost-effective to send a batch of blades to a pro for bevels between industrial steps?

Thanks,

-Daizee
 
Ah...but what does it take to have a skill? Time and repetition. ;)

Beveling, at least in my world, is easily the most difficult part of making a knife. It's something that does take some practice to develop the skills to do well. The repetitive precision required to do a bevel is much more demanding than the precision to profile a blade. when profiling a blade, you're dealing with a blade resting on a work rest, just moving the knife within the horizontal plane. When beveling a blade, you're working in all planes simultaneously.

--nathan
 
I have had these guys establish bevels on swords before. If you get them from India they have to be imported blunt -- and I have too little time these days to work on a sub-200 dollar sword for the better part of an afternoon.

http://www.grindingco.com/home.html


Send them something small first, see if it's to your liking. They're pretty old school. About a dozen guys working by hand on water cooled grinding wheels. They sharpen for most of the restaurants in Baltimore and DC, but they also do small-run odd-ball grinding jobs that human-flexibility is appreciated for. Call them and work something out over the phone. I'm sure you could mail them your blades. If their prices sound high -- try haggling.
 
Ah...but what does it take to have a skill? Time and repetition.
Click to expand...

indeed. I was really hoping to nearsource most of the project except for design at the beginning, project management, and final assembly.

I hope I'm blessed with the self-knowledge of the difference between what I COULD do and what I SHOULD do...

but ya never really know.

-Daizee
 
I'm not meaning to poke at you, Daizee...just encouraging you not to short-change yourself. You very likely have the underlying foundations necessary to be able to make a knife independently. You just have to uncover and refine the skill. :)

As for the project you're endevoring on right now, I think it's great and wish you the best in it. You obviously have developed skills in areas where I have none (CAD programming), and there is nothing wrong with putting those skills to good use. Keep us updated on the progress.

--nathan
 
Thanks for your vote of confidence, Nathan (nice knives and shop pix, btw!).

As for CAD skills... well, they're still developing too. Frankly I'm better at writing software than using it. ;-) Regardless, this seems like the right skill on which to concentrate, which will allow me to be most effective.

I've chosen this particular path because I not only want to create one or more knives that I'd like to own, but also to share them, for sale, for gifts, etc.. I don't have the time to manufacture anything in quantity, so investing $1k-$2k in equipment only to make a couple knives for myself just can't be justified in my mind.

Two years ago I got really into making holsters, and did a bunch. However, as soon as I started making them for others, it became abundantly clear that the fun and satisfaction rapidly disappeared and turned the whole enterprise into a time consuming chore. I would have very much liked to have been able to turn each successful prototype into a batch of production holsters, and indeed had a number of inquiries, but I am otherwise employed and the repetition, particularly in my limited free time, dulled me badly.

As a software engineer (professionally), I really like to solve a problem once. Good software is reusable. A great deal of work and thought goes into the intial design and build. Then an equal amount of work goes into "productionizing" it so it can actually be released for real use, after which it can be rapidly and inexpensively re-deployed many times over, or executed repeatedly solving an otherwise endless problem. This is how I think, for better or worse. I love the creative aspects of the craft - software, leather, steel - and the optimization of the process, but one-offs run counter to my temperment.

Unfortunately this means that I will never produce the fantastic works of art that so inspire me in this forum, but I hope to be able to satisfy my own creative urges and hopefully fill a local market niche through this other process.

Thanks for your indulgence with what I'm sure must seems to be a rather sanitized approach.

Incidentally, I made a bunch of calls this afternoon which finally yielded a shop on the MA/RI border that, at least in theory, claims to be able to put the primary bevel on a piece of knife stock. The fellow on the phone was very congenial, which always helps. This would fill the missing link in this so-far imaginary manufacturing chain.

Remaining steps include:
1) finding someone to help turn my crude CAD model into something a CAM system can actually use in reality
2) deciding on a handle material that gives me the most flexibility in terms of matching colors with sheaths, or at least not clashing too badly.
3) Hardening/Temper: a heat-treat shop should be able to do a straight heat/quench cycle. Should I expect them to do a temper operation on the spine?
4) decide on a coating or other sufrace treatment
5) get the damn ball rolling.

-Daizee
 
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