Re: Rhino + Guitar curves

John,

There are many more experienced with CNC and Rhino than me, but I've
built and designed a lot of guitars.

If you are already up and running with Rhino and have a system in
place for turning your designs into parts that's one thing.

If you are starting from scratch that's another. In the time it would
have taken you to learn Rhino, convert your stl file to tool paths
and code, then build your fixturing, cut your first part, realize a
few mistakes, try again... you could have made your master by hand
and probably had it cast.

In other words, going the high-tech route will be lots of work, trial
and error, materials and time. But you will learn a lot in the
process.

Going the manual route will save you time and aggravation and be a
more organic experience.

Sheldon

--- In CAD_CAM_EDM_DRO@yahoogroups.com, johnhe-uk@s... wrote:
>
> Hi,
>
> I just downloaded Rhino again to try and build a guitar body in
it. I am
> almost toally new to it in comparison to most of you guys. I
started by
> drawing a set of curves on the front veiw to create a contour, then
joined
> them and extruded out the shape to the correct length of the body.
That's all
> fine. Then cut out the pockets for the pickups, bridge, neck etc.
Easy.
>
> From there I needed to profile the edges of my contoured block
(Top and
> bottom contoured only so far). I guess I kind of cheated here
rather than
> finding out how to do it properly and used the fillet tool with a
massive
> radius set to create the first simple curves at the back end of the
body. I
> now have a top and bottom contoured block with a rounded end (The
end furthest
> from the neck).
>
> And now I'm stuck! :P I was working through the
tutorials, my duck was
> going great till it came to trimming the extruded neck into the
body. Dumb
> duck! Click inside the body inside the extuded area? I think not!
Being new to
> it I kept pressing F10 with my guitar body to try and get control
surfaces up
> to profile the kind of figure of 8 shape most guitar bodies are,
but alas 'Can
> not use control points on polysurfaces'. I also kept trying things
like using
> trim to cut the body profile but the cutting tool, my curvy line,
doesn't seem
> to want to do much cutting (Would I create the curve in top down
view then,
> anywhere vertically above the body, then use it to cut through?).
Could I use
> the curved line as a cut plane? Another idea was to create a curve,
extrude it
> down, extude it back, then use the difference tool to cut the shape
into the
> bodie's side. But there must be an easier way than that judging by
how much
> easier other things are in this! So, any help with this would be
majorly
> appreciated.
>
> My second problem was... If the body is contoured on both sides
how could it
> be machined in the real world on a knee mill? It could contour one
side, then
> you'd need to flip the block over and have it contour the other.
But as it
> worked it'd be slowly cutting the sides through to the other (To
make an
> almost fully rounded edge along the sides of the guitar) and I am
imagining
> the work piece could drop out of the block as it came close to
finishing the
> edges due to the tool pushing down on it, or atleast it'd deflect
somewhere.
> My answer to this was to leave something like 1cm uncurved on the
edges to
> hold the work in place (In the block it's being cut from), then cut
the work
> out with a saw. I was thinking of making this from something cheap
like MDF so
> the tool pressure wouldn't be massive on the contouring. I wanted
to create an
> MDF version then have it cast from magnesium for one seriously mad
guitar. A
> billet of the right size is a mere 800 Pounds stirling!!! So
machining it out
> from a billet is _not_ an option. Cast it's more than halved in
price. Does
> Rhino have a scale option where percentages can be used rather than
using the
> mouse to scale it? This would be to allow for the 1.3% shrinkage
from pattern
> to cast. Can any of you guys think of a way that the work could be
held once
> it's cast and contoured? Having it cast bring up the concern of the
neck
> binding or something else being just slight too small to fit the
neck so it'd
> probably need machining after.
>
> Of coarse, just buying a guitar is not good enough, you're on this
list, you
> know how it is! :)
>
> Sorry it's so long! Can you tell I'm stuck?
>
> Thanks for any help,
> John