Luthier/guitar building question

I asked this in other forums but I’ll ask here too since it is kind of CNC guitar specific.

I bought CNC files for from CNC3dguitars for a Gibson SG Standard a few years ago and I’m just getting to try them out now. I have only made bolt on Fender style in the past, so this is new to me. Any help or comments are appreciated as I’m still learning.

I milled a body and neck out of pine to test the files. The neck and body tenon toothpaths are not great and don’t really work well leaving large gaps. I’m going to see if I can modify them to work without screwing everything else up. This seems like something I could possibly fit with sharp chisels though.

I noticed at the end of the tenon on the top of the neck, it has the 3 degree taper, I assume to match the 3 degree taper in the bottom of the neck pocket. This makes it so the neck tenon is flush with the body on top. However, I am wondering how I can glue the fretboard to this since the taper starts where the fretboard would still be glued to the neck. This would cause a gap between the freboard and the end of the neck.

Is the back of the fretboard normally be tapered to match this, or is there something I’m missing about the taper? It seems like you would be bending the fretboard as you glued it on to match the taper on the end of the tenon.


If you’re talking about this… tapered neck pocket to accommodate a higher bridge…


Or even if you’re not…

The top of the neck and the base of the heal should both be parallel & flat.

There may be a good reason why the supplier of the files added a taper on the top of the neck.
But I can’t think of one. I would not want to have to fit a fretboard that way.


So on the model, the bottom pocket of the body is tapered as shown in your picture and gives it that tilt back. But, the top of the neck also has the taper. This makes the top of the neck tenon exactly flush the surrounding body. However, that top of the tenon taper means the flat bottomed fretboard doesn’t meet flush at the ends of the neck where the 3 degree neck taper is.

The last one of these pictures shows the neck joint where you can see the machining marks of the taper on the top of the tenon.

I took these images from where I purchased the model. They aren’t exactly the same but they should explain what I’m saying.

The bottom of the neck pocket is tapered where circled.

The top of the neck tenon is tapered where circled.

The taper on the neck tenon starts further back than the end of the fretboard, so the flat bottom of the fretboard would leave a gap since the top of the neck is tapered.

The top of the neck does not have to be, and in this case should not be flush with the top of the body.

Of course, I can’t find a good side view of an SG standard to illustrate what I’m saying :laughing:



[after seeing your last post]

Ah, OK. If the neck is at least flat where the fretboard attaches, it should be OK.
I didn’t realize the neck tenon (Heal) was longer than the fretboard in this design.

I would probably machine the neck flat, without the taper. Then machine it flat to the body after assembly. Especially if it’s a permanent mounted neck & you want to fill the gap & paint it to be flush with the body.


Thanks for this! OK, so I won’t machine the top angle tenon on the next one. Or I need to put the model together in a way that I know exactly where the fretboard ends and adjust the taper to start there.

The neck joint tool paths the file maker used are obviously very poor and need to be fixed either way, so it is just one more thing. I appreciate your help!

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No worries. Just had to be clear about what you were asking :wink:

If you have the fretboard, you can measure it. If you’re making it, you know the dimensions.
The 3° taper assumes you will use a stock Gibson bridge, or a bridge with a similar height.
It’s going to help if you have the other parts first.

You might want to leave a review at the site where you got the design files. :wink:

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