Cnc Guitar Questions

[StefanR]

I'm building a guitar for my final project in my Industrial Design class and I have access to a CNC machine and the appropriate programs. I plan it to be basically a copy of a Caparison Horus in walnut with a fixed bridge and a 24 fret, 24 3/4 scale Warmoth neck.

What I need help with is getting the guitar and pocket shape/dimensions onto the computer. I'm using MasterCAM to draw and it is not very friendly for complex curves. I've figured that the easiest way to get a guitar shape is the import a jpg of an actual size guitar outline and work from there. The only way I can see for me to do this is to trace a similar shape onto a giant piece of paper and then scan it into the school's computers, but that only gets me the outline and leaves the pocket locations a mystery.

Is there any easier/smarter way for me to do this? Does anyone know of a site where I can find outline and pocket dimensions? Any useful books or anything?

Thanks,

StefanR

[rbjem]

What I did with mastercam was draw the guitar in a CAD program and then import it into mastercam and create your toolpaths from there. If you donate to project guitar you can get access to tons of CAD files others have drawn. You could use these for the initial neck pocket drawings.

[thegarehanman]

Who draws out projects in mastercam? Do yourself a favor and get Solidworks; it's a very intuitive CAD program and has tons of plug-ins. Your school probably has it on most of their community pc's; I go to lsu and every pc on campus has it.

As for pocket dimensions, warmoth should be able to give you some, since they are selling you the neck, afterall.

At my school, IE's have to mill a small wooden sign on the CNC mill for their senior project. You IE's don't know how easy you've got it.

[davee5]

+1 to not using MasterCAM for modeling. I know they sell it as a package which is capable of being your standalone CAD/CAM program as it does have some CAD functionality, but it is remarkably convoluted and unintuitive. Heck even the CAM parts of MasterCAM is a pain in the rear to use if you haven't been trained (and even then...)

If you don't have access to any "real" CAD programs (Pro/E, SolidWorks, UG, Catia, etc.) and need to use the integrated version with MasterCAM, you best hit the manual to figure out how to do accurate placement using driving dimensions. Depending on what version your school has there should be some tutorials on how to do the basic CAD work too. The first 5 tutorials seems super, bordline boring, basic and useless, but if all you're going to do is make the outlines for pickup pockets and so forth, it's not that hard.

If you're having serious issues and need to use MasterCAM PM me and I'll dig up my old cheat sheet form training, it has most of the basic 2.5D commands spelled out.

-Dave

[MzI]

AutoCad. Thats all you need. Its just a simple line drawing and then use master cam to set your depth cuts. Just a word to the wise. It takes a lot of trial an error before you actually cut a guitar on the mill. Dont think you can just jump into it. It took me a good month and a half to two months of learning the program, the mill capabilities, and cutting in foam playing around with the actually drawing file before I even though about milling wood.

MzI

PS also take a look at the Pinned CNC vs Handmade thread at the top, that will give you a lot more insight into cnc milling

Edited October 31, 2006 by MzI

[A different Brian.]

I have two CAD programs, Bobcad and Rhino. My CAM programs are Bobcad and Milwizard. I'm getting ready to draw & mill my first guitar. Rhino is nothing short of incredible when it comes to drawing. Things that would be incredibly difficult in Bobcad are a breeze in Rhino.

If you're a student, you can get a great deal on Rhino at academicsuperstore.com, as well as several other titles.

[StefanR]

Thanks for all the responses so far!

I do only have access to MasterCAM and yes I have realized what a terrible, unintuitive dinosaur of a program it is. However, it is the only CAM program my school has.

I have a few further questions:

What formats (DWG etc) can MasterCAM open? I would much prefer to drawn in AutoCAD if that's possible.

What material(s) should I use for testing?

Thanks again.

[MzI]

What I did was draw in Autocad and just save it as a regular dwg file and just open it in mastercam. What you will be doing is creating a profile cut, no carve tops here, your just following lines and setting your depth cuts. This is where having a cnc mill is so great when you are doing flat top bodies because you can crank em out in like 5 mins for a full body. When you do want to do a carve top your going to want to do your drawing in autocad and then bring it into rhino or maya. Then export the 3d drawing as an .iges file, basically creating surfaces.

For test materials I recommend 2" rigid insulation from home depot. It comes in 2'x8' sheets they are like $15 each. Super easy to cut and no tool ware, plus its pretty damn close to the thickness of a guitar.

MzI

[StefanR]

Okay thanks.

I have a few more logistical questions about machining as well as design:

Generally at my school, we leave a border around our projects so we can drill the material into the router table. Is there any better way to fix it down so I can machine on both sides of my material?

The bridge I plan to use requires a neck pocket angle of about 9 degrees. Is it best to do this by hand?

I was hoping I could make my neck pocket heel somewhat like a JEM. Would it be best to order my neck without predrilled mounting holes?

If someone could tell me the distance between the bottom edge of the neck pocket and the saddle/bridge on a 24 3/4 scale guitar, that'd really help me get started. (I can't measure off my own guitar because it's a set-neck).

[davee5]

I'm only going to address your machining question as there are far more qualified people to answer your Ibanez questions (most of which will probably get a "use the search function" response since I know I've seen the answers out there).

By the way, even if you want to you won't be able to do from the outside as you described if you want to cut all the way through the material for the guitar outline. I might suggest bolting your workpiece down through the tremelo hole area (if the guitar you're building has one) or somewhere else on the body that you will eventually be cutting all the way through. However, even these options require that you cut teh body in multiple operations since you won't be able to cut the tremelo pocket if that's where your bolts are.

So, if you want to avoid bolts, nuts, strap clamps, etc. Then about your only other realistic options are using a vacuum fixture or double-sided stick tape.

If you have access to a a very nice spoilboard (vacuum board, as opposed to a vacuum fixture whichi hsa to be custom made for your project, which I don't think from your posts you have the know-how to do and from personal student experiences I know you don't have time to make), then consider using that. Even a spoilboard's partial vacuum at around 10-12psi will be holding your guitar down with a few hundred pounds of force. It's easy, it's clean, it's strong, but most student shops don't have them

If you don't have a vacuum fixture available then you might want to use double-stick tape. To the novice this seems like an idiotic proposal, but it's very common practice in the prototyping industry where people are machining metal, rather than nice soft wood. DO NOT, however, use double sided Scotch tape. I'm talking about the stuff from 3M, VHB or the foamy stuff. It's probably gonna gunk up the back of your wood but you can scrape and sand it off and you can just bolt down a peice of scrap metal to the CNC table so your teachers don't make you srub it down afterwards. Make sure you use a lot of it too, like cover the whole backside. That will be overkill, but it beats the hell out of having your workpiece fly off the table or chatter so much it ruins your guitar. In any case, industrial double-sided tape is probably your best bet.

As for the 9 deg angle, you're either going to have to refixture the part at 9 degrees, setup your coordinates to machine the pocket just right, and cut a second operation (hard for the novice). You could machine it (mostly) in the same operation as the other moves if your NC machine has good 3-axis capability but you said "router" in your last post which in the machining world means nice accurate 3D work is not in the capabilities of the machine. That would also require you to have modeled the pocket in 3D, which given the learning curve to do that in both AutoCAD and MasterCAM is probbaly not in the cards for you given the approaching end of the quarter/semester. Probably best to do this by hand.

-Dave

Oh, also for both Stefan and MzI, if you're going to do 3D machining in MasterCAM using imported IGES files, make sure the file you're saving has surfaces and outlines/edges turned on. Many programs like SolidWorks only export the solid surfaces and not the edges, which makes setting up paths for things like simple 2.5D pockets for pickups an absolute pain to program.

[MzI]

The best way to I found to hold the material to the table is to leave extra and just leave an 1/8 to a 1/4 inch from going all the way through the blank. Then afterwards just take a router with a pattern bit and clean it up. 9 degree neck pocket angle seems beyond excessive, you may want to recalculate that or draw a section of the neck pocket along with your bridge in autocad. For finding the dimensions of the pocket your best bet is to have the neck sitting infront of you and draw a full plan version of the body with all the frets and bridge etc, that way you can see where everything sits in relation to each other.

For the AANJ. I would do the profile of the pocket on the mill and then just carve it by hand. Its alot faster then trying to draw the thing in 3d.

MzI

Dave- I generally use Rhino and Maya for my 3d work which always has surfaces and edges when I export to IGES. As for the pickup routes, I also do them in profile cuts its so much faster because I generally use a 1/2" router bit on the mill so its two quick passes for the pickup and thats it.

[StefanR]

Thanks for your help so far!

Okay, all I really need to know to get started drawing is the distance from the neck pocket to the saddle. Or to anything really. It's the only dimension I don't have.