Official Luthiers Forum!

http://www.weaponeer.net/forum/uploads/ ... ograph.pdf

There really isn't much to this thing. The fixed pivot point is at the upper left. The two lateral arms are of equal length and the holes in the long arm and the arm at the left are an equal distance. The fixed upper pivot, the dremel bit and the stylus must be in line and that is all there is to that part. If I knew any math I could tell you how much reduction I have going but Veronica sat next to me in that class.

I just got to thinking the fact I used a headstock template for this inlay might throw you off. The little walnut cutouts are about the size of a quarter.

_________________
http://goatrockukulele.com

It looks to me like the ratio of the distance the dremel is offset on the cross-bar (the short side) to the width of that cross bar should be the same as the ratio of the short arm to the long (pattern following) arm to keep things undistorted - the reduction is then the value of that ratio.

Your link is back to your own thread, but the other thread just went by a few days ago, right?

Have you tried cutting shell for the inlays with it?

Neat idea. Thanks.

_________________
Jim Kirby
kirby@udel.edu

Very cool. I really like the idea of these things.....But is it really that easy to follow the inside line of your template?? I'd be worried about slipping the stylus off the template and causing a gap on the headstock. Or getting a kick back from the router if it hit some funny grain.
To figure your reduction just measure your template vs. the inlay. Your template is probably around 1.75" at the neck end, the inlay is 0.XX". Easier to figure that way than doing a big math thesis

[quote="Jim Kirby"]It looks to me like the ratio of the distance the dremel is offset on the cross-bar (the short side) to the width of that cross bar should be the same as the ratio of the short arm to the long (pattern following) arm to keep things undistorted - the reduction is then the value of that ratio.

At first glance you would think so but no. As long as the pivot, router bit, and stylus are in line you are good. The plexy router bar can be moved forward or backward to change your reduction ratio as long as you move the stylus to stay in line.

I fixed the link. http://www.weaponeer.net/forum/uploads/ ... ograph.pdf

A previous poster worried about kickback. Not an issue at all in fact far less than hand held as your leverage at the stylus is so great.

As far as difficulty holding stylus to line. I found I could use the plexy template and hold it back from the line the thickness of the stylus and use it for a guide. You could always make an inside form for the stylus to run against if you were worried about holding to line and I would do this if it were a logo or element I was going to reproduce many times.

I have not tried cutting shell. I don't think that would work well. The most I would try with good dust control would be to fine tune an already cut shell inlay. I could see cutting out the reduced inlay in wood, glueing that to shell then shaping the shell to match the wood. I have a glass grinder for stained glass that would make quick work of that.

_________________
http://goatrockukulele.com