Official Luthiers Forum!

Hello folks. I'm currently a senior in college with a degree in manufacturing. I have also been building/working on guitars for around 5 years. When I graduate and actually have some cash in my pocket, I'd like to buy a CNC machine for my shop. I have a ton of experience with CAD, CAM, G code, etc. but Im a little uncertain of what kind of criteria I should have when looking into buying a machine. What are some things you were looking for when purchasing a machine?

How much did you spend?
What do you use your setup for?
What tolerance can you hit?

I'm planning using the machine for bodies, custom bridges/hardware, inlay, and any other odd projects that I find myself working on (perhaps necks, but Ill probably just cut the heel on the machine then carve the rest by hand). Currently Im looking into getting a Shapeoko 3. I was interested in the Shapeoko 2 because its an easy machine to upgrade/modify, but they are going to release the Shapeoko 3 in the near future. I'd like to set a max budget at $2,500. The Shapeoko is only around $1,500 (I'd obviously like to save money if possible). My concern with the Shapeoko is the tolerance that it is capable of. It is theoretically accurate down to .001", but realistically around .005". I feel those are some loose tolerances if I want tight-fitting joints! A tolerance of .005 is PROBABLY more precise than what I could achieve when doing things with routers and hand tools, but its still something that makes me unsure of the Shapeoko.

I'm planning on running a small side business in the future building custom guitars, so I don't want to buy a junk machine or something that is going to give me sub-par results. I don't want to just ask "WHAT SHOULD I BUY?!" (I'm sure that kind of like asking which brand make the best guitar haha ) but could you guys point me in the right direction? I have a lot of experience operating a CNC maching but I don't know much about purchasing one! Thanks! -Alex

I bought a Laguna IQ with the BR controller, which they don't seem to be selling anymore, but I'm pretty happy with it. I use it with Rhino and RhinoCAM.

Total cost, including software and some bits, was a bit over $10k.

I'm still pretty new to the CNC thing, but so far I have used it for machining fretboards, inlay work, and a lot of jig-making. I make radius blocks, and things like that very easily with the CNC. I also set it up to make my headstock veneers, which I'm doing in a way that's more complex than it sounds and that I couldn't feasibly do without CNC. As my CAD skills improve, I'll get a good model of archtop top and back plates and then use it for those too.

I haven't measured tolerances, but it's pretty darned precise.

As for tight-fitting joints, I'm not sure I would trust any machine or jig to get a joint perfect. Even at PRS, they have a nice Fadal, and yet they cut their neck tenon a hair oversized on the Fadal and then sand it down by hand to get a perfect fit. It seems like a prudent and efficient approach.

X Zero in Canada offers several nice machines at good prices. I'm not sure about how it works now, but when I got mine a few years back it was pretty much a bunch of parts that I had to put together--not a kit per se. But it went together into a very nice machine--much stouter than anything else I found in its price range. I've been very pleased with it, especially for what I have in it (mine is 24x48x8 with heavy ballscrews, rectangular linear bearings and 3/4 inch thick aluminum parts combined with a couple of 80-80 extrusions for rails. I have about 4K in it including the electronics--of course that's several years ago).

I think that George might be selling some turn-key units now, but in general the X Zeros are a lot more substantial and bigger than the Shapekos you mention, and start out at about the same price point.

Dave

Unless you get a heck of a lot more bang for your buck in the USA than in Australia, I'd say that your better off saving up for more of a machine. With a budget that low you are going to be at the very very low end of capabilities. Nothing more than a toy that certainly would leave me completely frustrated and wishing someone talked me into something better.

I couldn't find anything commercially that was capable of what I wanted in a size suitable for my needs. Either way too big, or just too lightly built and way too much money for what you were getting. So I built up my own machine with better than 24" x 48" work area and 12" of Z. It's all in metric measures, but that gives you an idea.

A 24,000 RPM 2.2kw spindle with an ATC and 6 position tool rack. Helical rack and pinion on the X and Y axis with a 25mm ball screw on the Z. All steel construction with solid aluminium working surface. Right now I'm into it for $15,000 AUD including 15 tool holders, collets and tooling. But tooling is an ongoing thing that can get frighteningly expensive.

_________________
Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

Unfortunately, the reality is that your budget is far to low to purchase a machine. It is not to low to build a reasonable machine.

That is what I did. I actually built two. The first one lacked rigidity. The second one works quite well applying lessons learned from the first.

I actually have access to a Haas VF3 at a local community college. My DIY machine works so well I prefer to use it. If mine had an ATC I wouldn't ever bother with the Haas.


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yep your budget is low. also the Shapeoko doesn't have the envelope nor the minerals to take side cuts is electric bodies or mill out control pockets either. you're gonna need a bigger boat for that one. Nema 17's are a little wimpy and a 24 dcv spindle is thrifty also. i'm not a fan of belts either and those exposed v rail systems get dirty very quickly impacting performance.

the Shapeoko looks like a fun little hobby machine that can do inlay, engraving, rosettes, etc.. but probably only good as a stepping stone into something more substantial when you are ready.

imo, finance your way into a used machining center and a place to park it.

Thanks for the input. What resources/websites did you use to learn about building a CNC? I've been poking around on google but I haven't found much except for machines built from MDF

The granddaddy of all resources is the cnczone forums. It has all the answers, but sometimes that is the problem! Very overwhelming.

I literally spent a couple of years with analysis paralysis. I bought the Momus plans, downloaded the Joe2006 plans, bought the Rockcliff plans, and downloaded cnc router parts plans. I studied them like it was a Master's Thesis I was preparing for, then built a total crap machine.

However, in building a crap machine I broke the analysis paralysis and learned a lot.

I would love to make a third one now, with what I've learned; but this one works well and I don't have the time for such a big project. Too many guitars to build!

I can offer the following advice as you start your research:

1) don't get too hung up on claims of fraction of a thousandth accuracy. You are cutting wood. Wood moves, it shrinks, it expands. It has grain, figure, fibers. Great guitars have been built with hand tools by guys who couldn't see a thousandth if their life depended on it.

2) size it right for your job. I have a friend who bought a 4' x 4' kit. Great kit, but too big. It's a white elephant in his shop. On the other hand, in designing mine I forgot to factor in the distance from the edge of the z plate to the actual cutter and have just a smidge too little x travel. My ideal machine would have 20"x24"x6" actual cutting envelope. My math errors caused me to have 19"x20.5"x3.5".

3) Simplicity in the electronics is your friend. A gecko 540 controller, a uc100 USB to parallel, basic step motors pre wire with DB9 connectors. KISS.

One last thing: CNC is a tool, not magic. It replaces a machinist on an end mill or overhead pin router. It has a steep learning curve even when you have the machine and all the software. You still have to be the engineer who designs the parts. You still have to be the draftsman who create accurate technical drawings. A Cnc machine can't cut what you can't draw. You still have to mill the stock it cuts from. You still have to assemble the parts the cnc mills into a guitar. You still have to sand, align, apply a finish, set up after the parts are assembled.

CNC is a LOT of money and steep learning curve for a single, admittedly versatile, tool. Money that could be used for a good band saw, table saw, jointer, router table, hand tools, etc. All of which you will still need.

I hope all this helps!


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you should look for a work envelope to cut a 17" body and do necks. then rigidity and hp, if you can make two or more of the same part with only a few thousandths difference that's all you need. I use to hold .0005 in steel and aluminum, woods a lot different, a few thousandths is great.

If you have some (lots) of free time and no one to give you the "rabbit hole" speech, building one would be the most affordable and super fun.