WIP: Designing and building the new Resolute with the help of CNC.

[aarongough]

Hey guys!
So as you may know over the last few months I bought and then partially rebuilt a Vertical Machining Center (large CNC milling machine). I captured this process on video here:

[video=youtube;bP158y03VxQ]https://www.youtube.com/watch?v=bP158y03VxQ[/video]

I realized last night that I hadn't done a WIP thread in a long time so I figured I should start one covering the process of designing and building the new version of my Resolute knife with the help of the machine!

After the machine itself was finished I had to bide my time while saving up money for a compressor and other tooling to get the machine running. Toolholders, pullstuds, cutting tools, a vise and so on... Lots of accessories needed to get a machine like this actually turning out work! (Thanks god for tax returns!)

About 2 weeks half ago I finally got everything setup at the shop, then it was time to get the design side of things setup!

A machine like this isn't terribly useful without CAM (Computer Aided Manufacture) software to tell it what to do. You can hand-program simple shapes but anything beyond that really requires the use of CAD/CAM to be efficient. In the past I've used a friends copy of Solidworks for CAD along with HSMexpress for CAM. I looked into buying a full license for myself but it is incredibly expensive ($5,000+ initially, plus $1500/yr maintenance fees).

While looking for alternatives I came across a program called Fusion 360. Their base price is $120/month for the 'pro' version ($30 for the basic version) but they have a deal where if you're working on an un-released product they give you 12 months free.

I downloaded it and started to learn it, and amazingly I actually like it better than Solidworks! I then spent about a week re-drawing all my designs in Fusion. Progress was actually much quicker than I anticipated:

Using this program is a massive plus for me as I can actually recommend it to others when I show it in my videos, it's not some unobtainable piece of software that no-one can afford.

After getting the shape of the blade/tang/scales modelled up in CAD I started working on how the parts were actually going to be machined. I think this part of the process is going to undergo a lot of revisions over the next little while to get things as efficient and effective as possible, but first I wanted to give each part a complete run-through just to make sure I understood exactly what was involved and to highlight any weak points in the process.

First I setup a toolpath that would drill the pin/lanyard holes in a blank, then skeletonize the tang:

[video=youtube;0_H9F7opiQU]https://www.youtube.com/watch?v=0_H9F7opiQU[/video]

This produced a bar of steel shaped like so:

The idea was then to use the pin holes as locators for the next operation, cutting the outside of the blade blank. I can't hold the bar in the vise for the next operation because I need access to the edges of the stock, so I had to make a fixture to locate the bar using the pin holes and to hold it firmly in place using a clamp that's recessed so it doesn't get in the way. Here's the design I came up with for that purpose. The blue part is the blade blank, everything else is the fixture:

I then had to machine the base of the fixture. I made a mistake in the programming of this and tried to drill a 0.625" deep hole without pecking (it was late and I was tired). Ended up breaking my only #7 carbide drill:

https://instagram.com/p/29DEV5CKAF

Once I'd replaced the drill with a regular jobber length HSS #7 drill I drilled the holes like I was supposed to, with pecks! I then machined the ends of the steel bar square and relieved the top surface to the rough profile of the knife to provide clearance when the fixture is in use:

[video=youtube;FVcMKdxVF8U]https://www.youtube.com/watch?v=FVcMKdxVF8U[/video]

This was a bit scary because it was the first time I'd attempted a big cut on the machine. In this case I was using a 3/8" solid carbide endmill to take a cut 0.625" deep and 0.15" wide on the ends of the bar. It's taking me a while to adjust to the idea that the machine is actually fine with taking cuts of this size and even bigger!

I'm not using coolant or cutting oil because I'm used coated carbide tools that are designed to be run dry.

The fixture came out well! I had to sand down some 0.1255" dowel pins to 0.1249" to get them to fit snugly in my drilled holes, but that didn't take too long:

I then machined the clamp that goes at the top of the fixture. This took 3 separate setups because of it's shape, but it wasn't a particularly demanding part in terms of how close the tolerances had to be.

I then clamped everything together with my bar of steel in the middle of the fixture 'sandwich' and setup to start machining the profile of the blade! I was worried about chatter near the tip of the blank as it's relatively unsupported there, but it worked fine in the end! The blank came out well!

This is the first actual prototype for the Resolute 4.5, so it's exciting to finally have it in hand! Pleased with it so far!

The plan over the next few weeks is to go through the process of making each of the parts for the knife, then assemble them in real life to see how everything fits together. I'll then be going back over my process and refining it as I go, making changes to get everything to work better together.

For instance I think it may be better to setup my fixtures so I'm able to mill the periphery of the blade blank in the same setup that I drill the pin/lanyard holes. The relationship between the pin holes and the edge of the blank needs to be perfect to ensure there won't be any 'step' felt around the edge when the tang and scales are glued together... Lots of little things to iron out still!

I also still have some work I need to do on the machine: it needs an enclosure so that I can run an air blast to clear chips away from the cutting area, also need to setup a vacuum system for machining G10 and a vacuum clamping system for holding various fixtures and so on.

I will be updating this thread as I progress, let me know if you guys have any feedback, questions or requests!

-Aaron

 

[samuraistuart]

Very cool Aaron! No questions or requests from me....just interested in the thread! Thanks again for your help in the past. Always enjoy your posts.

 

[jdm61]

Very cool. I know it is going to be slower than water jet. or laser, but because you have the machine, is doing it this way CHEAPER than an outside water jet/laser job when you factor in your cost of end mills, etc?

 

[Lo/Rez]

Thanks for the post.

 

[aarongough]

Very cool. I know it is going to be slower than water jet. or laser, but because you have the machine, is doing it this way CHEAPER than an outside water jet/laser job when you factor in your cost of end mills, etc?

Hey mate!
That's an excellent question. I had a think about this for a while this afternoon, and I do actually think it should work out to be quite a lot less expensive. There's a couple of factors that go into it:

1) When I was having an outside waterjet guy make blanks for me I was paying about $10.50 each for them, for that same amount I could pretty much buy a tool per blank that I make
2) The tools should last quite a lot longer than you'd likely expect. Because I'm using coated solid carbide tools with fairly conservative modern style toolpaths (constant engagement toolpaths) the tools should last quite a while, I expect to get 30+ knives from one set of tools, but at this point that's really only based on intuition which could well be wrong.
3) The big one: blanks cut via waterjet still required a lot of my time for finishing, whereas ones coming off the mill practically won't require any of my time.

When I was getting blanks done by waterjet I was actually pretty disappointed with the edge finish and the rather loose tolerances. All the pin holes had to be waterjet undersize and then drilled out if I wanted snug fits, same with the lanyard hole. The edges all had to be cleaned up on the belt grinder because they were tapered and because the finish wasn't so great. The choil in particular was a total pain to finish after waterjet.

I actually had a waterjet blank sitting around at the shop (I used to use it as a template) so I shot a side-by-side photo showing the edge finish of waterjet versus milled (waterjet is the top one):



If you click on the images and have a look at them full size, especially near the butt of the blanks you'll see one of the other big differences: no tabs. Grinding off all the tabs left on a waterjet blank was always a pain!

If I had to use either waterjet or laser for cutting blanks I think I would likely choose laser, my experience with waterjet overall was not terribly positive.

-Aaron

 

[aarongough]

Very cool Aaron! No questions or requests from me....just interested in the thread! Thanks again for your help in the past. Always enjoy your posts.

Thanks for following along Stuart!

 

[aarongough]

Thanks for the post.

No worries mate!

 

[aarongough]

I didn't get as much done at the shop today as I would like, I'm sick as a dog at the moment unfortunately.

One thing I did get done was to modify the tool that I'm planning to use to put the rounded contour on my handle scales:

This is a 1" radius round-over bit from Lee Valley. It's got carbide cutting edges which should make it hold up pretty well when cutting G10, but makes it a bit of a pain to modify. I went through 2x 36 grit Blaze belts in order to grind enough off the end to get the clearance I need:

I ground about 1/2" off the end so it won't interfere with my fixture that will hold the handle scales. Here's it is in the toolholder for the machine:

Will be a little interesting to program the toolpaths for that beast as it's not a standard shape, probably a bit of trial and error will be required.

 

[Daniel Rohde]

I'm looking forward to how this comes out! I was wondering what video camera you are using for your youtubes?

I will be keeping an eye on this thread! Thanks Aaron!

Daniel Rohde

 

[Nathan the Machinist]

my experience with waterjet overall was not terribly positive.

-Aaron

I agree. Waterjet is really more a roughing process. There is no comparison to the accuracy and finish of a fine milled surface. And your mill appears to be working well.

We frequently accumulate cutters that are worn out on the end, but have an area near the top of the flutes that is new or nearly new. If you generate used cutters like this in other processes they can serve a second life profiling blades. They're basically new, they're already "used up" and paid for, and they do an excellent job profiling blades. Since the carbide is essentially free, the cost of profiling a blade on a CNC mill is just time. That's a real, non-zero number, but it's less than getting them waterjet and the end result is way better.

And if you want, you can add chamfer mills and reaming and engraving and fullers etc that a WJ simply can't do. You have a tool changer

Rock on Aaron :thumbup:

 

[phorizt]

Thanks for sharing this. Your videos really helped get me into knife making and I appreciate you continuing to document your processes. It's kind of cool to see how your videos have gone from how to build a filing jig and HT a knife in a can to CAD and CNC knife making.

 

[PT Doc]

Looks like a ton of fun. Good luck with everything. It will be fu to see how the actual cost changes excluding the cost of the machine.

 

[Kevin Wilkins]

What I don't like about any of the software deals where you rent the program on a monthly basis is this: What will you do when they say that instead of $130 a month, it's now $150? $200? $500?? You'll pay or you will have no access to any of your own work anymore. I downloaded it when it came out, then canned it pretty soon.

I also won't go for Adobe's CS software anymore for the same reason. They won't give a contract for more than a year and after that they can raise the price to whatever they want.

Also $130 a month is $1560 a year. I bought Solidworks a long time ago and paid it off in a few years. Now I own the software outright, am off of maintenance as I still use XPpro on 2 Dell Workstations and have zero desire to ever buy another box with a MS OS. If Solidworks comes out native on the Mac OS, I will upgrade at that time.

When you use your machines and software to make a living you have to think about the longer haul.

 

[Josh Mason]

Pure wizardry. I'm just awestruck by that thing, and these processes.

 

[JCaswell]

I totally agree. There is NO comparison between Waterjet/laser and CNC.
At best and "intermediate precision" process. Iffy finishes. Kerf taper. Loose tolerances .... WJ is a convenient blanking operation.

 

[Kevin Wilkins]

Neither water jet nor laser produce finished contours for high quality knives. They *are* both much more efficient for blanking knives than directly milling the blanks from big plates of steel. Both waste a lot less steel, especially when combined with automatic positioning software – you get the maximum number of parts from the sheet with a minimum of waste. Laser cutting requires annealing before final contour milling which you save with water jetting. Both are up to +/- 0,2mm tolerances though, maybe even better depending on the material thickness.

If you buy steel in narrow bars, it doesn't pay to use either one, might as well use the mill or the bandsaw.

 

[aarongough]

I'm looking forward to how this comes out! I was wondering what video camera you are using for your youtubes?

I will be keeping an eye on this thread! Thanks Aaron!

Daniel Rohde

Hey Daniel!
For my videos I'm using the Panasonic Lumix G6, it's a camera that shoots both stills and video. It does video especially well and I'm very happy with it! I use the Panasonic Vario X 14-42mm lens with it.

-Aaron

 

[aarongough]

I agree. Waterjet is really more a roughing process. There is no comparison to the accuracy and finish of a fine milled surface. And your mill appears to be working well.

We frequently accumulate cutters that are worn out on the end, but have an area near the top of the flutes that is new or nearly new. If you generate used cutters like this in other processes they can serve a second life profiling blades. They're basically new, they're already "used up" and paid for, and they do an excellent job profiling blades. Since the carbide is essentially free, the cost of profiling a blade on a CNC mill is just time. That's a real, non-zero number, but it's less than getting them waterjet and the end result is way better.

And if you want, you can add chamfer mills and reaming and engraving and fullers etc that a WJ simply can't do. You have a tool changer

Rock on Aaron :thumbup:

Thanks Nathan! I'm very pleased with how the mill has come up, given the results I'm getting from it so far I definitely got a complete bargain! Edge finish is not as good as a new machine would turn out, but in a few years I'll replace the spindle and motion hardware and it will be good as new! It's very comforting knowing my way around the guts of the machine!

Added processes like chamfer milling and engraving are an important point! Also the possibility of doing bevels on the machine too.

 

[aarongough]

Thanks for sharing this. Your videos really helped get me into knife making and I appreciate you continuing to document your processes. It's kind of cool to see how your videos have gone from how to build a filing jig and HT a knife in a can to CAD and CNC knife making.

Thanks mate! I appreciate you following along!

I plan to return to my roots soon for some instructional videos using basic tools, trying to get a functional CNC process squared away before I do that though!

 

[aarongough]

Looks like a ton of fun. Good luck with everything. It will be fu to see how the actual cost changes excluding the cost of the machine.

I think that excluding the machine the overall cost will be about the same. Material cost is the same, belt cost will be reduced but I will have more expense in cutting tools.

If you factor in the machine then the cost has definitely gone up. Once I start getting more knives out though the cost should get spread out nicely...