Official Luthiers Forum!

After the responses to the last thread I started (and how long it's taking me to finish these necks I'm working on) I'm seriously considering taking the step toward home CNC. My plan is to start making chips in the fall of 2011. To achieve that, I'm thinking of the following steps:

Research - pretty much continuous.

CAD - Step one is to draw up my parts in CAD. Currently, the OS-X version of Rhino is still free so I can work on that at no cost for the moment. I'll probably go with moi3d if I have to buy. Once things are drawn up, I can start planning in CAM.

For CAM, I've got a few ideas but am open to suggestions. The stuff by Ventric cut 3D is only $300 but looks sort of limited. What are you guys using?

For the machine itself - I'm wondering if anyone has any experience with the CNC shark. They've got a new one out here: http://www.nextwaveautomation.com/CNCShark_Pro.aspx and here: http://www.nextwaveautomation.com/CNCSh ... _Plus.aspx which also comes with the cut 3d software bundled.

The big downsides that I see is that is mostly plastic construction (which isn't necessarily that bad), limited Z travel and worst of all, a very small router mount. Perhaps a spindle could be mounted in that space but would the machine be rigid enough for say a 1.5hp spindle.

The big plus is that it looks like it's about half the cost of a K2 or ShopBot. The other is that with dinky routers like that one could by a couple of them and keep them pre-loaded with bits. Basically I can probably afford a shark where as I may need to look for donors to afford the real deal. So a few questions but first, how I imagine that I'll probably use it to build about 5 instruments a year, possibly more down the road. CNC parts would be the neck (the hard part), bridge, internal structures, Possibly hole drilling.

How bad is it?
Could it handle this type of load?
Is there a re-sale market for CNC machines and what value might it have in it in a few years?
I'm looking just for turn key systems or close to turn key systems. If there's a "complete" kit (i.e. comes with absolutely all hardware and I just have to bolt it together) I'd be interested in that too, especially if it's an upgrade to the shark. What I don't want to do is spend months tracking down components and machining parts to get something up and running. My goal is to build instruments, not a CNC machine.

Anything else I'm not thinking of?

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I'd put the resale market on low end CNCs at something between that of computers and that of bicycles. A few years of wear on a low end machine won't leave much value.

You're not in a hurry, so you don't need a whole lot of spindle to get your work done. That'll help immensely with a lightly built machine. You'll mind the extended runtime a whole lot less with a spindle, since it'll be about 1/100th as loud.

Reviews here:
http://www.cnczone.com/forums/commercial_cnc_wood_routers/74080-cnc_shark_pro.html
http://www.sawmillcreek.org/showthread.php?t=79882

Can't say much else. For going on 4K I could build an awfully spiffy machine, but I've also got the tools to do it. There are guys doing pretty well with semi-finished kits, though I don't know much about that end of things. Check out CNCZone.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I owned one of the original Sharks. I don't regret owning it because it was my introduction to CNC and served its purpose as that.

BUT, here are the downsides as a guitar-building tool.

1. The Colt is underpowered.
2. None of the models have enough travel to machine the full length of the neck without moving the material.
3. The Y screw is not well supported and so you get a lot of whip along Y. In other words, instead of getting a night straight/flat cut, you get a wavy cut.

My calls to their support number about #3 went unanswered.

I sold mine to a guy interested in making Christmas ornaments, which I feel is a much more suitable use for the Shark and so far as I know it works well for him in that regard.

My new machine is a Camaster Stinger. It's between $6 and 7k when configured similarly to the Shark but it is a welded steel frame and heavy, heavy duty throughout. All rack and pinion drive, etc. It's a new machine and there are the usual caveats with being an 'early adopter' but it's so, SO much more machine than the Shark for not all that much more money. Yes, the $2k+ difference is a lot of money, but not if you end up selling the Shark at a huge loss like I did...

I spent all my time with the Shark fighting it to try and make it something that it wasn't...that's a frustrating place to be. If you see CNC as being part of your future, I would highly recommend skipping the Shark and going straight for a machine that you can use without a ton of compromise, and for a longer term.

That's kind of what I was afraid of. I'm thinking I'm scratching that off of my list.

Looking around some it looks like a kit may not be such a bad choice after all. I'd like to use the CNC to drill holes as well as rout so perhaps I could used the saved cash to pick up a variable speed spindle as well.

I could swear I saw a link to a fully equipped kit that was all Al construction on here somewhere but I can't seem to find it. What kits are people using and would anyone recommend anything in particular?

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Mike, what are you seeing as far as alignments on the stinger? How flat is the steel table and how is the alignment between it and the X and Y axis travels? Are the X, Y & Z axes all in good alignment to each other within, say, .001"/ft?
These are some of the things that none of the manufacturers, at least what I've found, will specify in their literature/advertising/website etc.
Guess you could say it's ONE OF my pet peeves.
Nelson

Hi Andy,

Another option for you is a good used one. Here is the one I have:

http://luthiersforum.com/forum/viewtopic.php?f=10106&t=24603

I bought this one through a government auction site for about $3500 (Just over $4000 by the time it hit my shop). This machine has 49" x 49" work area, a 3.2 hp Perske spindle with VFD. Three 1.5 hp vacuum cans for the table (I don't use them!). It needed about $100 worth of timing belts and the odd collets that Perske uses. Once those were replaced the machine works great. It came out of a University and came with the proprietary operating software which seems to work fine. This machine has a replacement cost from Precix (the manufacturer) of $25 to $30K. They were actually bidding on it as well but I snuck in at the last minute and beat them out (don't you hate guys like that!).

Anyway, if you look at the government auction sites (like the IRS sites) and some of the other used and repossession sites like RTR Services often have CNC's on them as well. Also ebay has 13 pages of cnc machines.

I just thought I should offer another option for you.

Shane

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Canada

Hi Nelson,

I'm sorry I don't think I have good answers to any of those questions. I haven't done any real measurement of anything yet (just got the machine in OCT). I have one issue that I'm struggling with on the X axis (I think). I'm not sure if it's backlash (is there such a thing as backlash with R&P?) or slop in the mechanism or what, but cutting simple circles, the result is not always perfect. It might even be a software issue - I'm still trying to narrow it down. Obviously, I'm still very much a noob at all of this - my only experience being with the Shark and a couple months here with the Stinger.

And my experience with the Stinger hasn't been a perfect one. There's the aforementioned circle issue and also the fact that delivery took 3x longer than my quoted lead time with a few promised delivery dates in between passing unnoticed. . As a matter of fact, between those issues I'm not sure I would even recommend the machine to anyone (at least not yet). But I'm finding these frustrations a lot easier to deal with than my situation with the Shark which was that the machine was just inadequate for me, at a very base level. So while I don't feel like I necessarily know of a machine that I can recommend for Andy, I feel good about recommending against the Shark based on my experiences with it.

(Edit: Shane's post right above mine is a perfect example of the point I was trying to get it which was that, if Andy is going to make even a modest investment, better to go with something that you can hopefully grow into, unlike the Shark which I felt like I had outgrown as soon as I opened the box...hopefully he can avoid that buyer's remorse that I experienced.)

Oh, and I opted for the MDF table for the Stinger and am just using a fly cutting bit to surface a spoilboard every so often.

-Mike

Andy, you should really consider building one. There are several of us here that are building from the Joe's CNC plans and it's very straightforward. The advantage here is you can customize the machine to your specific needs and if you are new to CNC it gives you a well needed education. The forum is topnotch and there is a very strong community of 'Joes' out there that are very willing to help. There are three different guys within an hour drive from me that have all offered to have me visit their shops and see their machines...

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Mitch

Honestly I have very little interest in scratch building a machine. Kit I might do but I just don't want to do the full blast scratch build simply in the interest of time. When I pull the trigger, I want to get to making chips as quickly as is financially possible. That probably means a kit or used or something like that.

Is there anyone here in South East Michigan who's willing to be my CNC Sherpa?

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Hi Andy,
I'm a new owner of a K2 2514. It has unsupported rails like the shark. The frame and table which I bought new on Ebay( for considerably less than the K2 complete package) seems to be a nice tradeoff for the low cost it cost me in comparison. The rails were beefed up in a redesign and the aluminum table is bolted to the frame making for a nice low budget machine. Now granted, I had the router and software here and felt comfortable assembling a motor/controller package to it. Still I think my capital outlay was under $2k. It came with the router mount for a PC 690. The nice part of the machine is that although one axis is only 14", it will accept material up to about 19" wide. The work length is 25 and open ended so it can accomodate longer material. After my fiasco with the Pcncautomation machine, I'm looking forward to seeing what the machine is really capable of. I can tell you the Z axis is quite the piece of hardware and I am pretty impressed with it all overall. It has antibacklash acme screws. These need to be lubricated often from what I can tell. I just got the recommended grease today, so I'll go over it all again. This machine is something to consider anyway. The only hard part was figuring how to configure mach3 to the machine as I hadn't done that at all before. Also, I know I looked at the reviews and people complained about flexing in the unsupported rails, but with the bigger rails they redesigned in 2009, I think that is minimized so much more. Also, I only run it about 50-60 inches per minute, as I'm in no rush with what I do. So to conclude, after some testing, a body and a couple necks, I'm pretty happy with it.

So still looking around and I've narrowed it down to a few choices and I'm wondering if anyone has any experience with the following:

Romaxx WD-1 http://www.romaxxcnc.com/sbwdspec.html This one looks pretty interesting and, they're a local company so I could pick it up. Has all ball screws but stepper motors with an option for feedback. No servo option as far as I can tell. With the feedback option, this comes in almost a grand cheaper than:

K2 KG 2525 http://www.k2cnc.com/shop/proddetail.as ... 2DG&cat=26 Which is slightly larger and comes with servos out the box.

Finally, the ShopBot Buddy looks kind of interesting but it just irks me that the table moves on a single rail type thing (pinion drive?) rather than the gantry with two rails.

I know it shouldn't but it does. I'd say that at the moment the Romaxx is the front runner mostly because they're local. The K2 looks like it's a slightly better machine over all and it's got a bit bigger capacity but, it's also bigger and my basement is only so big.

$1000 question - with CNC routers of this caliber, is it possible to rout curves (non-circular arcs) that are glue ready with their mate? e.g. with a template, a router and bushings, I can rout two curved mating pieces that will mate exactly with almost no glue line. Will a CNC router provide joints that are glue ready? Will servos make a difference?

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Congrats on getting closer to making a decision. Re: your question, I have no experience with the machines you're looking at but my gut reaction is that if you can do it with a hand held router you can also do it with a reasonable sturdy machine. I'd make a quick rough cut then make one final finish pass taking off a few thou to get a smooth edge. Steppers vs servos is just a matter of doing the math. A typical stepper motor runs at 200 steps per revolution. Controllers are capable of breaking that down further with something called micro stepping. My controller is capable of up to 16 micro steps per full step but the manufacturer recommends to start with only 2 and increase if necessary. I'm running at 4 so that's 800 microsteps/revolution. My screws turn at 2" per revolution which equals a resolution of .0025"/microstep which is probably better than runout on an average router. It's my understanding that servos are effectively capable of infinite resolution - and feedback which is another topic, but for woodworking I doubt that they are necessary. I've cut plenty of circles, arcs and 3d shapes and they feel perfectly smooth. Hope that helps - also hope I did my math correctly.

I'll pipe in since I have a Shark. Like Andy, for my first go around with CNC, I wanted a pretty much turnkey solution with manufacturer support and I didn't have a lot to spend. Rockler had a pretty good sale on them, so after some research I got a pro plus. I got mine with the idea of making some parts, cutting inlays for my more commonly used shapes (while being able to control the refraction angle on the shell), and building jigs. Maybe an archtop plate here and there for good measure. I bought it understanding that it is a light duty machine.

It really works well for my applications. I don't try to hog off massive amounts of material in one pass, so Y axis flex hasn't been an issue. They are offering a longer bed model on special order now that has fully supported Y rails, but mine is the standard model. I've used a high speed dental handpiece as a spindle for cutting inlays with complex shapes and can easily cut a curved inlay that nests inside another inlay with press fit tolerances--I've had to intentionally introduce a gap to allow room for some glue.

I've done some banjo fingerboards including all fret slots, inlay pockets, hole for the fifth string nut, fancy ogee "frailing scoop" and index holes on the underside for glueup later on with acceptable speed and great precision using the Colt router and a variety of end mills. I've also built the jigs (with matching index holes) for roughing out necks on a shaper. I still prefer to carve my necks by hand, but hogging off the bulk of what needs to be removed with a shaper is fast and more appropriate in my case than CNCing one. It leaves a nic clean surface, and the precision of the jigs off of the shark maintains the tricky centerlines of a five string neck where everything goes together as it should.

I wanted CNC for doing the work that a machine can do better than I can by hand without taking away the fun parts of building or the things that give a handmade instrument it's character. So for me, that's mostly using it to replace non-CNC router jigs that I've used in the past. I also wanted a way to build reproduceable jigs (to replace as they wear out), and prototype things without doing it on expensive wood. I cut my first few fingerboards in mdf until I got them right. For this kind of use, the shark is all the machine I need. If I were mass producing electrics, it would be a different story. I would buy one again in a heartbeat for my needs. It's not a heavy duty machine, but if you work within its limits, it is capable of doing most any lutherie chore. The new 52 inch Y axis model would probably handle most neck making chores too, along with a sturdier Y axis.

You can undoubtedly get more machine for the money, but the Shark worked right out of the box, and within a couple of hours of assembly, I was cutting parts successfully.

Hope this helps.

Dave

OK so, I'm down to two finalists in my search with a solid (but more expensive) plan "B"

In the lead by a hair - the Xzero RaptorX - http://www.xzerocnc.com/forum/viewtopic.php?f=4&t=3

24x36 Raptor Frame
3/4 inch Aluminum
1610 & 2010 ballscrews
20mm Hiwin rails and blocks
Motor mounts
couplings
NSK 3200 bearings
Table top
wiring harness
router mount
425oz motors
Gecko
Power supply
8" Z Axis
E-stop
Setup
~$4500

This machine has specs that seem to out do the K2 but it's made by a one man shop. I'd drive up to pick it up and because of that, he's willing to put it together and test it for me before I buy.

In a very close second is the Romaxx WD-1: http://romaxxcnc.com/wd1product.html With the specs page here: http://romaxxcnc.com/sbwdspec.html

Over all, the Romaxx looks a bit more polished but uses in house rails and costs a little more. There is a "closed loop" option which might be good for a CNC novice such as myself which drives the cost to almost $1k more than the Xzero . They are also only about 45min from my house so I could easily pick it up there. I've heard some very good things about the Xzero as well saying that this guy can't be making much money off these machines at all.

Any guidance on this would much appreciated. They both seem like great machines!

oh, and plan "B" is to go with the K2 - lots more money though.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy if I were going to buy one of these machines, I would choose the second. I think the first one is built heavier, but the guy is from Canada and depending on where you live, that = long distance in case something goes wrong. The other guys are 45 minutes from your house. To me, that is a no brainer. I would also take a hard look at the closed loop option and it has nothing to do with lack of experience. It has to do with knowing where you are! Hope everything works out.

Mike

Toronto - where the Xzero is from is about 4 hours-ish from my place. Yes, a long way and it is pretty much a one man operation.

The "closed loop" system on the Romaxx by the way is not a true closed loop - their system doesn't return an absolute position, it's got an encoder and will catch a missed step and shut down the machine. So, not true closed loop but it could save some pieces.

I hate the indecision end game of a big purchase like this which is somewhat ironic as my day job is selling really expensive medical imaging equipment.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy if the first machine is only 4 hrs away, and there is no true feedback for position, I would go with the first machine. They look like much better machines in the photos than the second, but would have to make that determination by using them.

Mike

After much worry and stress (not really) I've decided that I'm going to go for the Xzero machine. Last night I spoke with a fellow who's a long time home CNC maker and he reassured me that between the two machines, the Xzero is the way to go and is simply in another league than the Romaxx.

I'll probably pick it up in a month or so!

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Good choice... Looks like a stout machine.

Hey guys, after a long wait, I finally got the goods about a week ago and finally today had a chance to do a bit of assembly work. I must say it was worth the wait. This thing is solid as a rock. Admittedly, it's a little rough around the edges and is definitely "some assembly required" but, the rigidity of this frame is just off the hook. I went to a friends place a few months ago to check out a Romaxx WD-1 and while it's a mighty fine machine, this thing is just so much stiffer.

I spent about an hour adjusting the rails and have them parallel to the 8080 profile to within 3 thou for the full length of the rails. I checked the 8080 profile (which is pretty massive by the way) with a high quality starrett straight edge and by eyeball, it looks to be within a thou or two of flat. I'm sure that with a few more measuring devices I could do better but, I'm not putting together a metal working machine and I don't have enough environmental control to maintain tolerances better than that anyway.

I've attached a picture of the X ballscrew as well - 25mm In diameter!!!

Anyhow, to summarize, this is a very high quality and rigid machine. It is not turn key and a little rough on the edges but, if you can handle putting one together without an instruction manual, it's definitely worth considering. Unfortunately, I'm going to be traveling a lot over the next few weeks but I'll try and work on it and get pics and vids posted as I get to it. Although I haven't cut with it yet, I'm quite certain it's going to fit the bill.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy..congrats on the CNC Router! I am sure once you cut a few parts you will wonder why you didn't order it sooner. When are you planning on your first part?

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Brad
Avon, OH

Andy,
That machine does look like it is build solid!
What is the purpose of the extrusion mounted across the rails?
Perhaps a removeable fixture for small workpieces?

That's one section of a T-slot table. I just put one on there to measure things for square and plumb and such. There are T-nuts in the 8080 profile. When complete, the whole table will be that T-stot stuff but, I may make an MDF spoil board to use while I'm learning to use the machine. Those extrusions aren't exactly cheap and I don't want to wreck them while I'm learning.

Brad, I'm still waiting on the spindle which should be a couple of weeks which is not really that big a deal as I've got some travel coming up - shows in Edmonton, Calgary and Winnipeg with my Bandura group, and then two weeks (but not in a row) of work travel shortly afterward. I still have to run a 220 circuit for the spindle as well. So, it could be a couple weeks.

For first parts, I've made a little piece that's like the first scroll you helped me make.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

That's a good decision. The shark is just an expensive toy, and yours has much better components. Looks terrific.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Great looking machine, Andy! Since my earlier reply on this thread, I have also picked up an XZero Raptor. It's a great machine, and I've been able to throw some pretty darned heavy work to it without so much as a hiccup so far.

As far as the Shark goes--here's my take on it. As I said earlier, the Shark is a light duty machine, and as long as you work within its limits, it performs well. How does it stack up next to the Raptor? Not really a fair comparison. The Raptor is a much more solid machine. But it's still not quite a "plug and play" adventure. The Shark is. I learned a lot quickly on the Shark, and that experience made it much easier for me to get the Raptor running like I want it to fairly quickly. Had I not gone down the Shark path first, I am quite sure that I wouldn't be having the success with the XZero machine that I'm having now. The Shark was a great trainer, but capable of doing much more than you would expect from a "trainer."

The XZero, on the other hand, would probably have frustrated me had I not previously gone down the "plug and play" path, but that's just me. It's a fine machine, capable of small shop production work, and built with nice heavy duty components for a machine this size. George, the XZero proprietor, has been great to work with, even though I bought my machine used. My machine is a "first generation" Raptor, and is absolutely solid as a rock. The improvements he's made up until Andy's machine make it even more solid (overkill perhaps!). It's great to see someone who is really trying hard to build a top notch machine and keep it within pricing that a small shop can afford--and trying to continue to improve it at the same time.

So, all in all--I can recommend the Shark because it is a great place to learn, and it's capable of doing some real work at the same time. It's really intended to be a sign maker and hobbiest machine, but it can do a lot more than that if you work within its limits. I'm glad I got one, since I think I would have given up on CNC if I hadn't gone with a turn-key solution first. I can recommend the XZero, because it's a really solid machine at a very reasonable price. It's light-years beyond the Shark in terms of solid build, and for a machine of this class, I can't imagine one that is more solidly built or more capable.

Dave