Homemade CNC router for knife handles?

[pendentive]

I'm a knifemaker (www.kosterknives.com) interested in exploring CNC-made handles. I've been dissatisfied with the CNC companies I've tried to work with so far...mostly because of tooling/setup costs. I want to just do 20 or so at a time which is a lot for a custom knifemaker and not so much for a CNC shop. So, I think they are upcharging me to make me "go away" and frankly, it's working.

I do all my own 2D CAD and have a buddy help me with the 3D IGES stuff. I'd be willing to learn whatever software I needed to.

I really just want to find a way where I can cut handles out in a consistent way...in larger quantities.

I've been doing some reading on the DIY CNC Router projects and am very excited because it seems the way to go (vs. a dedicated CNC). The largest piece I'd need to cut from would be 12"x15"x1" - so I could even build a small one if it might save a few bucks. That's all I would use it for - cutting out knife handles (3D milling/shaping...not just profiling) from sheets of canvas micarta, small boards of cocobolo and individual blocks of Ironwood.

I am a bit leery of just buying a bunch of parts only to have it take up a lot of time I could be making knives...and maybe not go together properly, etc.

Got any suggestions?

Is there anyone that builds one from a kit for sale? I'd probably rather go that route than do it myself.

Am I chickening myself out? Is it not that hard/time-consuming to build?


Let me know what you guys think.

Dan

[jalessi]

Dan,

For the money you cant beat K2CNC.

They sell there 2514 25" X 14" router frame for $1,295.00 on eBay, you should be able to complete it for less than an additional $1000.

http://tinyurl.com/yjc7er3

Welcome to the Zone,

Jeff...

[FandZ]

I would think for a knife handle you would want a 4 or 5 axis machine. Unless it's purely 2.5d, it would take too long to do 20 at a time. Come to think about it, I remember a knife maker using a 5 axis machine. You may want to check out Doughty drive 4th and 5th axis's. http://www.doughtydrive.com/products.html

Maybe get the k2 cnc machine as Jeff is suggesting, a 4th axes indexer, and 5th from doughty drive. You probably would be looking at 4 or 5k once you are done but you could make some incredible handles. I think at minimum you will need a 4th axis.

I just checked out your site. Nice knives! The Damascus Bowie is incredible.

[lunchtrayrider]

are the knives assembled as two halves? if so a regular 3-axis might suffice. romaxx has a smaller machine that is ready to go. a bit more, but it would be ready to go out of the box.

[jalessi]

It looks like the majority of Dan's knife handles or scales are flat on the back side. If that is the case, they would only require a three axis CNC.

If the back side requires machining then a simple fixture would be much cheaper and a whole lot easier to program verses the complexity of a five axis machine.


Jeff...

[pendentive]

Correct - I think I only need a 3 axis machine. There is contouring in the handle but a 3 axis should be able to handle it - from what I've seen on cnc router videos.

If my best option is to buy one already built, then I guess I'll do it. Am I going to end up spending ~2000-2500 for it whether I build it myself or not?

I was hoping for a DIY kit recommendation or better yet, someone who puts kits together.

But I'm so entralled with the idea that I'll probably get one no matter how I have to get it. Just need to save up the funds.


Thanks for the kind words on my work.


Any more suggestions?

Dan

[FandZ]

Originally Posted by pendentive Correct - I think I only need a 3 axis machine. There is contouring in the handle but a 3 axis should be able to handle it - from what I've seen on DIY videos. If my best option is to buy one already built, then I guess I'll do it. I was hoping, though, for a DIY kit recommendation or better yet, someone who puts kits together. Thanks for the kind words on my work. Dan

I'm thinking once you see the amount of tool changes you will have to do etc, a 4th axis indexer will seem mandatory. It just makes since to me. but I'm not a machinist or that cnc experienced. But adding a 4th axis isn't that hard or expensive. Something you could think about down the road.

Have you seen the kits offered by fine line automation? It's not as good as k2 cnc, but it is a capable machine.

Here is a link to their thread and has all the info on the machines and user experiences. http://www.cnczone.com/forums/showthread.php?t=73670

[ger21]

Originally Posted by FandZ I'm thinking once you see the amount of tool changes you will have to do etc, a 4th axis indexer will seem mandatory.

How does a 4th axis get rid of tool changes??

[pendentive]

Here are some pics - you guys know best - let me know if a 3-axis or 4-axis would be better for creating handles like these (from 2 different knives):







The plan is to cut them from a sheet, leaving 0.100" thickness (not cutting all the way through the board) and then cut them out on the bandsaw.

The important part for me is having them consistent. I plan on doing light finishing on them after I put them together....which, incidently, will be done with corby screws that require a counterbore (seen in the pics above). This is the only place that needs good precision (0.005"). I plan on routing them a tad oversize (0.030") which I will then clean up at the belt sander.

Let me know if this makes sense - or if there is a better way.

Dan

[awerby]

with a 3-axis mill. I don't see the need for a 4th axis. But you should think about how they will be supported in the sheet - you don't want them being cut loose and flying around. Some small tabs that keep them connected would be a good thing to add - they are easily cut off and the stubs sanded away.

Andrew Werby
www.computersculpture.com

[pendentive]

Originally Posted by pendentive The plan is to cut them from a sheet, leaving 0.100" thickness (not cutting all the way through the board) and then cut them out on the bandsaw

See quote above - I do plan on leaving them on the sheath (no loose parts). I was going to cut it down to almost bottom and then leave "tabs" like you say. I'll come back in with a bandsaw to finish the profiling.

Dan

[FandZ]

Originally Posted by ger21 How does a 4th axis get rid of tool changes??

Correct me if I’m wrong, but the angle of attack can continually change with a 4th axis. Once you start looking at the time it takes to do certain jobs (like the knife handle with 2d and 3d characteristics) at an acceptable resolution with just an end mill vs. an end mill and a ball end mill, the end mill and the ball end mill will take less time to get the same resolution with a tool change. If you do it with a 4th axis, then the angle of attack can change and you can get better and faster results using just an end mill without a tool change or just a ball end mill. Plus you have 2 sided machining.

I really don't see how it wouldn't be more practical to do it on a 4th axis with fixtures. Time, tooling, end results, the whole shebang.