Question for CNC users: ES top and back

[ricky1918]

Hello gentlemen,
I'm starting this thread because I may have access to a CNC for free only for the next weeks. This is because a friend of mine studies design at college and has laboratories with cnc machines and other stuff.

Now, let's say I'd LOVE to build a ES style guitar, using the veneers like Gibson/Epiphone does.

Watching Jason Beam's ES build on youtube, he uses some kind of mold to give the shape to the veneers, while he glues them together (in the air tight bag).

As I have the chance to use the CNC, I'd like to make my own mold.

My question for you, CNC users, is merely about how to draw it.

The plans online have the measure for the top of the guitar, but I think I should not use these measures to make the mold, as it would lead to the top being much more arched than it should.

How would you proceed with this step?

Here is a quick demo I made today on Rhino, just to show what I'm talking about.

 

[BuffaloHunt]

I'm in the middle of doing an ES style build as well.

Mine is more like an ES-225. With a single florentine cutaway. I'm at the point where I'm trying to design the curve of the top. I will be using a CNC router to make a mold, just like Jason Beam did with his. I have all my laminations ready for the mold and vacuum press, I just gotta get my head around 3D modelling on a CAD program.

 

[pshupe]

If you can't wrap your head around the 3d then do 2d. Offset the lines very tightly and you can carve profiles around each line using a ball nose bit. I did that for my first carve top on my CNC and it worked out really well.

cad model -

CNC toolpath -

I found doing it this way almost identical to having a 3d model carved with a ball nose bit and it was much quicker to machine actually.

Regards Peter.

 

[ricky1918]

Thanks guys. Buffalo, you need to post pics for us!!

Pshupe, thanks for your input, but I feel like I wasn't clear enough in the question. Sorry, language is a limit sometimes Let me try to rephrase it.

I don't want to route the top directly, as I'd do in a Les Paul or similar guitars.

I wanted to make the mold for the archtop, and then use a vacuum press to give the laminates the final shape.

My question was about the measures of the mold.

I have no problems drawing it, but I don't know if drawing it with the measure I found for the top would lead to a "wrong" arch for the top.

I don't know how to make myself more clear, I'm just thinking that in order to have the correct arch for the ES top, I'd need to make the arch of the mold "more pronounced"


I may be just wrong. But I wanted to have some ideas from you fellas, as I don't want to waste this HUGE opportunity.

Thanks!!

 

[bearskinz]

Thanks guys. Buffalo, you need to post pics for us!!

Pshupe, thanks for your input, but I feel like I wasn't clear enough in the question. Sorry, language is a limit sometimes Let me try to rephrase it.

I don't want to route the top directly, as I'd do in a Les Paul or similar guitars.

I wanted to make the mold for the archtop, and then use a vacuum press to give the laminates the final shape.

My question was about the measures of the mold.

I have no problems drawing it, but I don't know if drawing it with the measure I found for the top would lead to a "wrong" arch for the top.

I don't know how to make myself more clear, I'm just thinking that in order to have the correct arch for the ES top, I'd need to make the arch of the mold "more pronounced"


I may be just wrong. But I wanted to have some ideas from you fellas, as I don't want to waste this HUGE opportunity.

Thanks!!

Hi Ricky, I believe in the Jason Beam video you mention in the beginning, he experiments to answer these same questions. He makes the molds oversize according to the thickness of the laminations, but then reworks it after doing the first test. Can't remember the details, but I bet you can figure it out if you watch the video closely.

 

[pshupe]

OK - Odds are if you just found drawings on the internet they are probably not that accurate. Also the mold should be more extreme than the final result because the wood bounces back slightly. You will probably have to test to figure out how that works.

Are you asking for measurements of a mold for a ES-335? That seems to be the question?

Regards Peter.

 

[ricky1918]

Also the mold should be more extreme than the final result because the wood bounces back slightly.
.

This is what I wanted to be sure of

Thanks, gentlemen, I'll open up my Rhino in the next days and see what I can do.


Cheers!