Few newbie questions about CNC

[thedonutman]

Ok, Im interested in getting a guitar/bass made partially using CNC(there are a few CNC workshops around my area)

When I say partially, I mean I will drill some holes, shape the neck, do contours/carving by hand. So basically, I just want the body/neck shape cut out and the cavities routed.

1. So what information do I need to give to the guy at the CNC place to do this?

Ive found various dwg files off this forum and various other places, but ive gathered they are just 2D and are not enough.

2. How long does this take to do? If I find good plans, will it just be a 1 shot thing? or will it need trial and improvement.

3. Is CNC machining reasonably perfect? eg. is there any chance of end grain tearing out(like what happens if your unlucky with a hand router), bits slipping/breaking and chipping wood.

4. How much should I expect to pay for this kind of thing?

Thanks for reading, and forgive my ignorance

[ger21]

1) a 2D drawing should be good enough, but an angled neck pocket might be tricky if you need one.

2) Depends on a few things. If the drawings are perfect, it shouldn't take the programmer long to get it ready to run. Also depends on what size the material is your working with, and how easy/difficult it is to hold down. Whether it's a 1 shot thing depends on how good the guy is.

3) Tearout is always a possibility, especially when using highly figured woods. There are ways to minimize it and try to avoid it. Depends on the guys experience. Bit's should never break or slip if they know what they're doing.

4) I'd say ~$200 for a one off job, maybe more, maybe a little less.

If you can carve the neck by hand, I'd say just do the whole thing by hand. Make a few templates and use a pattern cutting bit.

[thedonutman]

Originally Posted by ger21 If you can carve the neck by hand, I'd say just do the whole thing by hand. Make a few templates and use a pattern cutting bit.

I'd like to do that, but Based on my previous experience I can say that I am not very good at making patterns, and if I was to buy them they are very expensive over here and I dont think it would be worth it

And also, I dont have a band saw for cutting out the body shape or the neck.
With my previous built, I got a guy at a workshop to thickness the wood and roughly cut it out on a band saw. I only have a Jigsaw, which isnt powerful enough to cut through 1.5 inches of Sapele smoothly

[ger21]

Then I'd recommend having them cut an MDF sample first before cutting the Sapele. To minimize tearout, make sure the blank is larger than the body by at least the bit diameter all the way around. Any time the bit is trimming small amounts from the edge of a board you risk getting tearout.

[Drakkn]

Originally Posted by thedonutman I'd like to do that, but Based on my previous experience I can say that I am not very good at making patterns, and if I was to buy them they are very expensive over here and I dont think it would be worth it And also, I dont have a band saw for cutting out the body shape or the neck. With my previous built, I got a guy at a workshop to thickness the wood and roughly cut it out on a band saw. I only have a Jigsaw, which isnt powerful enough to cut through 1.5 inches of Sapele smoothly

Hi - what guitar you wanting to make - Is it a custom shape ? or will a standard shape ,I have a load of dxf file for cnc machines - let me know what you are after.If you need any help let me know - I am in west yorkshire if that is of any help to you.