Z height

[banjomanwv]

Ive got a question. Im looking to buy a CNC that will cut a banjo neck.
Right now we have 2 Shopbots and both are desktops and we have a thriving inlay business and were wanting to expand. So, the heel of a banjo is about 2 3/4 tall......right under 3 inches.....if my table is the surface that my Z is counted from and Im using lets say 2 inches for board to mount up on etc (just a number is all) how much Z do I need in oder to cut that part? 7? 8 ?

[steve_g]

Banjoman…
Are you cutting the neck profile or inlaying on its surface… That will determine how long of a bit you will need to use. The length of the bit comes out of your Z axis… looking to the future, is a banjo neck the tallest you’ll ever want to cut?
SG

[banjomanwv]

Just cutting the 3D profile of the neck, I inlay the board separately. The only reason I am buying this is for necks, and that will be the only thins besides inlays and banjo stuff ill be using it for.

[scottp55]

I imagine you've already seen this, but just going to add it anyways in case.
http://www.talkshopbot.com/forum/showthread.php?20271-Desktop-with-9-5-inch-Z-modification&p=169470&posted=1#post169470

scott

[cr2]

Check out this video starting at minute 14...shows cutting that part of the neck: https://www.youtube.com/watch?v=1HHIl1ggQls

[banjomanwv]

Scott I have seen that but a banjo neck is to long for the desktop so that is not an option for me unfortunately

[banjomanwv]

https://www.youtube.com/watch?v=ZtKUAwgoTOQ

that's what ill be doing

[banjomanwv]

https://www.youtube.com/watch?v=ZtKUAwgoTOQ

they evn use a shop bot buddy but Ive emailed numerous times and they are not forthcoming with any info on how they do it so..????

[banjomanwv]

my set up will be different because I will have the TR slot cut out and the other parts planed flat, ill only be doing the back contour of the neck

[steve_g]

Banjoman…
Back to the original question. If I understand your setup, it looks like 8” of Z is absolute minimum!
SG

[MogulTx]

Banjo man- what are the dimensions of the desktop? I once had a project that was significantly longer than my 4 x 4 machine... I was going to put registration pins in it so I could cut part of the file, then move it and cut the other bit.... but I finally realized the part would fit diagonally. Banjos are about 39"- so take away a 13" diam. pot, ( and add back a little for the heel)... you are looking at around 27-29"??? You might be able to do it on the diagonal.....

[banjomanwv]

Ok, to be more realistic, probably like 7.25 but I want 8 to be on the safe side so with that said here is another question. The 48X48 shopbot says it has a nominal cutting area of 6 inches but actual Z is 8 inches...what does that mean and would it work/

[banjomanwv]

It actually does fit on the diagonal but the Z would not work though

[Chazz]

I was looking at doing something similar (guitar neck) with my desktop and even with just the 4" Z I think it fits. In my case, I plan to put extra material on the sides. It can be garbage grade wood as it will be completely cut away when done. I plan to cut the front with 2D for most of it and 3D for the front of the head. Then flip it over and do a tiled 3D cut for the back and then carefully cutout. I have shifted to using a combination of bolts through the spoiler board into nuts in the aluminum base and some home-made clamps that are held by same. I have not completely worked out the details but I think that the 4" Z is enough for this one. On the off chance that I am a little off in my calculation, I have the 5.5" Z kit that I have not yet put on that I can install. Once I am successful, I will post my overall procedure here.

[banjomanwv]

Awesome, cant wait