A Special-purpose Pin Router

[Ken Bennett]

Hi Ya'll,

This is my first thread. I hope you find it useful.

The other day we were starting to carve to tops of our new archtop guitars. At a certain point we realized it would be good to go ahead and precisely define the edge thickness and the line at which the arching starts to rise above the edge. Later this flat area will be scooped out to create what violin guys call the channel. Benedetto calls it the recurve.

The goal was to make something quick without having to go to the hardware store. It worked beautifully. We took a few snapshots during construction, so I thought it might be a good thing to share.

A base for my laminate trimmer router sitting on a mahogany riser at the end of a corian table

The corian table, with some of the layout and drilling done, and the mahogany rails that will support it

Table drilled for the pin assembly

[Ken Bennett]

The pin is a 1/2" bolt screwed into a 7/16" hole and sawed off. The top of the pin filed smooth and the corners broken slightly.

Assembled and aligned, the pin protrudes 7/64" above the table.

The pin aligned with the bit in one axis

[Ken Bennett]

And the alignment looks pretty good from this angle too.

Double stick tape will hold the 1/4" template to the underside of the archtop guitar top.

The template attached to the top, ready for operation

[Prostheta]

Aha! I see where you're going with this one! Excellent idea. Would using multiple templates and cutter depths be impractical for roughing in a full top carve?

[Ken Bennett]

Aha! I see where you're going with this one! Excellent idea. Would using multiple templates and cutter depths be impractical for roughing in a full top carve?

Yes, that would be a good application for this kind of tool, but with this setup you could only go so far. The clearance between the bit and the riser is only 2". That gives us just enough to do the edge. We just wanted to get a consistent edge thickness and define the boundaries of the arch. A duplicating carver or CNC is better for a full top carve.

[ScottR]

I hope you get to post some in process shots for those of us that have never seen a pin router in action.

SR

[verhoevenc]

Or you could just use a safe-t-planer and some pencil lines. Especially since you're carving TO said flat spot.

Chris

[Ken Bennett]

I hope you get to post some in process shots for those of us that have never seen a pin router in action.

SR

ScottR,

I shot some video right after we made the thing. Over the weekend I'll try to edit and post it.

A full-fledged pin router is really an amazing device. It can do things that our little special purpose rig can't do. You can raise and lower (plunge) the router into the work with multiple preset stops, use different diameter pins and bits. You can also set the pin at different heights which allows for multilayer templates. For example, cutting a control cavity, you could have a template in two layers. The first layer could be used to cutout for the recess for the cover plate; then, with the pin raised up into the second layer, cutout the main cavity.

verhoevenc,

Safe-t-planer and pencil lines for stock removal (rough carving) sounds like a good way to go. I've always wanted one of those. We've been using a big chisel and mallet. My customer is also an apprentice, so I wanted to do the first plate mostly by hand, then switch to a more efficient power method. We're making 2 of these guitars, so there will be 3 more plates to carve after this one.