binding rebate on carve top guitar

[thegreatwaldo]

I have a file for an electric guitar (stl file) where the top is carved but thicker at the cutaway. What would be the best way to go about putting a 6mm high 2mm thick rebate into the top that would follow the top edge of the guitar. I have imported the 3d Carve file stl but am not sure how to convert it into a vector. I have attached a picture of a top so that its easier to understand what i;m after.
Thanks in advance
Waldo

[ohiolyons]

The only vector you can generate from an stl would be its outer edge "automatically" by a press of a button.

You could manually draw vectors on the stl. Could be tedious depending on the complexity of the STL.

Not really sure what you are trying to do?

If you want to add something to an existing model/component (STL) draw a vector, create a component and add or subtract that component to your existing STL.

Not certain this answers your question.

[ohiolyons]

just googles what a binding rebate was see




some thing are better done without using a CNC. Don't wrap yourself around the axle of doing everything with a CNC. Always use the best/simplest way. I know it is heresy, but sometimes that doesn't involve a CNC.

A friend of mine puts it this way, Thanks Thane Lorbach

"We are next store neighbors and you are having a BBQ that I'm invited too.
I own a Helicopter. I could come in the helicopter, but I could just walk around the fence!"

Some things are not better done on a CNC

[ohiolyons]

I have never tried this.

1 Use the one button MODELING, Create a vector boundary around selected components
2 do an offset inward
3 do a norma1 rough and finish cut
4 do a profile toolpath and project onto 3d model

[thegreatwaldo]

Hi Ohiolyons.
I shall give that a go and let you know.
Cheers Waldo

[ger21]

I have never tried this.

1 Use the one button MODELING, Create a vector boundary around selected components
2 do an offset inward
3 do a norma1 rough and finish cut
4 do a profile toolpath and project onto 3d model

I was thinking the same thing. Should work.

[Jim_in_PA]

Doing the binding rebate on an arched top guitar via the CNC is a bit tough, but if you want to try, you need to establish your vector for the entire edge you want to bind (it will be an open vector), offset it inward for the thickness of the binding you intend to use (2mm based on your description, which is on the thicker side for binding), create your toolpath to cut outside of the line and set your start depth as appropriate. That's for a body where the edge is at the same level all the way around. But if the level of the edge varies, you can check the box to follow the 3D model. My experience trying that for edge treatment (in the software) has been to not necessarily get the cleanest cut...I'm in process of a body design "as we speak" and actually have decided to avoid the edge treatment or binding for the design as a result. If I still wanted the binding, I'd resort to using a more traditional method of a trim router with a binding specific bearing guided bit that is suspended so that the base clears the raised areas of the body. Sometimes we have to be really careful with the idea that the CNC is the best way to do everything, especially for guitar making which I have been learning keenly in the past few months.

BTW, I suggest you do the binding cut before cutting the neck pocket or have a closely fitted scrap block to place in the neck pocket before running the binding tool path. The area where the top of most guitar bodies engages the neck pocket is very often at a steep angle and having that support reduces the chance of tear-out where the biding comes up to the neck pocket.

[thegreatwaldo]

Thanks Jim.
I started doing the binding on guitars 40 years ago with a chisel (still got the scars to proove it. I've been using the overhead up and down jig with a bearing cutter, which works ok, but not having much space I would rather do it with the cnc machine.
Cheers.
Waldo

[Jim_in_PA]

Waldo, I suggest you try (on a "scrap body") to cut with the follow 3D model checked and see if it provides acceptable results. I haven't tried it "live" but wasn't overjoyed at what I sew in the rendering when I tried it recently for a similar, but different edge treatment on a body I was designing that had contours along the edge.

[thegreatwaldo]

Hi Jim

I just figured out that I can manually edit the z height on the g code to compensate for the carve. If anyone on the forum knows of any good g code editor I would be happy to try it.
Cheers
Waldo

[Adrian]

It's just a standard text file so anything that can edit text will work. Notepad is the obvious as it comes with Windows for free. Personally I use EditPlus and Scite for all my text editing needs but there are hundreds of them.

[thegreatwaldo]

Hi Adrian

I'm totally new to g code I have to adjust the z code to match the curve in the cutaway. I have a toolpath where a fixed rebate is cut and was wondering do I have to edit the Z value line after line or is there a G code editor that would automatically calculate the z values between 2 points. For example first line has a z value of 5 and 20 lines later the z value is 10. Or do I have to get my old o level maths book out and look up pythagoras formulas ?
Cheers
Waldo

[ger21]

Did you try to project the toolpath to the model?

[thegreatwaldo]

Hi Ger
I just tried that and it seems to work. I shall have to do some work on the model but it looks like i'm getting there.
Cheers
Waldo