Official Luthiers Forum!

_________________
If God had wanted us to drink beer, he would have given us stomaches.

Don, I've had an on again off again CNC bug for awhile and have done a little research though in no way profess to yet have the expertise to attempt to build one from scratch let alone run one.

There are a number of manufacturers who sell kits and ready made machines who quite often put their machines up on eBay that also provide links to their website. It might be worthwhile contacting them for suggestions as to motor specifications that they match up with their machines as a supplement to places like CNCZone.

My brother and I are kicking around the idea of either purchasing a small machine or building one together from scratch.   My brother works in a large machine shop and has spent a number of years programming and running various types of CNC machines for metal applications (lathes, mills). If in our travels we uncover any gems I will be sure to think of you and pass any relevant info. After reading all the info John Watkins posted on the MIMF I was pretty much disuaded from ever trying to build one. I suspect that it's a lot tougher than the DIY sites suggest.

If I wasn't so time constrained I would take a CNC course at a community college. Might be worth looking into if your day job and family life permit.

The frustration I've had with the plans I've seen for sale in my google searches or eBay surfing is that most use Dremels or RotoZips for a spindle and therefore of limited use for building guitars.

A handy thing about working in a machine shop is that you can make some of the parts for your CNC there. Fadal, the company who made my machine, makes the machines on other Fadals.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

OK. How do I upload a pdf or a zip file? Can I even do that?

This plan is for a proper router/spindle powered CNC machine. It has a parts list (also lists suppliers for many of the parts for you Americans), and I've got .dwg files for most of the structure. I also have a doc on choosing motors, which may be helpful.

_________________
If God had wanted us to drink beer, he would have given us stomaches.

Joel, at a minimum the material have would be of value as reference material.

I've not seen many plans for proper spindle machines!

If you want me to email this info to you, just PM me your email address and I'll send it to you. The email will come to over 2Mb, so if you're on dial-up it may take a while.

I reckon you're right Anthony. At the very least it's a place to start and an interesting read.

_________________
If God had wanted us to drink beer, he would have given us stomaches.

Hey guys, I would be happy to let you know the specs on my K2 machine parts, if you are interested. I have a K2 3925G machine (this is their luthier model). It uses a porter cable router for a spindle...and it holds about .002" at worst and is better in most cases.

It uses servos & a gecko drive along with linear rails and ball screws. The machine is run via the Mach III controller software, which is also a very capable piece of software.

FYI, I spent about $9000 US to get setup with the K2 machine with 8" Z, auto tool height setter, T-slotted table, Mach III, Rhino CAD, Rhino CAM Basic, and Rhino Art. I went through a stage where I considered building my own machine...but I decided I would rather do more woodworking than electronics & CNC design!

We use Fadal 4020's at work...and these run about $85 or $90k apiece, but I'm sure they would also make nice woodworking machines. At this point I am a hobbyist...if I ever get deeper into this stuff, I will invest in more production friendly equipment. For software at work, I use MasterCAM (figure about $12k for a 3D capable version), SolidWorks ($5000), and Rhino ($800). In terms of software, I highly recommend the Rhino package as the most bang for the buck by far.

_________________
http://www.PeakeGuitars.com

I have a Fadal 4020 and use it for, well, everything. Kevin Ryan, Taylor Guitars, and Jim Olson are also using Fadals, so they do alright as woodworking machines . Using a Fadal only for wood is sort of like taking a rocket launcher to go duck hunting, though.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Judging by last hunting season, I could use that rocket launcher on grouse...! I can't hit them to save my life!

~~~
If you don't mind my asking...what kind of feed rates & chiploads are you running on the Fadal?

We have some older Fadal's (these have the Fadal Controller) and we can run these up to about 300 ipm. The newer ones have the 15k spindles and Fanuc Controllers...these seem to run pretty well at a bit over 500 ipm.

I've looked into the CNC routers quite a bit and there is a wide range of products in the $8k-80k price range. Here's some of what I've found:

On the low end you have the K2 type devices, which I think are a good solution for the serious hobbyist, or for someone who is cutting smaller parts, or for someone who does not need to produce 50 parts a day.

There are a ton of products in the mid range....25k to $50k. Typically you get tool changers on these machines, higher powered spindles, and usually a bit more speed. From what I've seen, this class of machine usually loses accuracy as you run it faster.

The higher range, $80-$250k are where you find more serious production machines. On the low end of this are the Fadal's & such. On the high end, you have machines like Northwood and Komo. These machines let you run greater than 250 ipm (some go up to 1000 ipm), and typically have more rigid frames, tool changers, industrial strength controllers, and high speed & power spindles.

_________________
http://www.PeakeGuitars.com

I'm not sure exactly what to answer for feeds and chiploads. In general, I tend to run fast and shallow so my feeds are much higher than normal for the cutter sizes I use. Using a 1/2" cutter in anything aluminum or softer I pretty much never go below 120IPM and up to 400-600 on some operations. I set my feed rates and depths independently for each operation on each part.

Generally, the fixturing options for the part and the DNC speed control how fast I can run the machine, rather than the limits of the machine itself. If I can save time on setups using light fixturing then it might require lower feeds but will work out to my advantage in the end.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services