Project Guitar :: Home Made Radius Boards

	This shows the router sled attached to the base board. The router is attached to the sled by it's edge guide, using one of the edge guide bars inserted through it's channel in the router base, and through two corresponding holes in the sled. This setup lets you use tapered shims at the back of the router to ensure the cutter is exactly perpendicular to the baseboard. The arm of the sled is long enough to cut any common radius, by simply drilling more pivot holes the appropriate distance from the cutter.
This shows the whole jig. The arrow points to a wood screw attaching the sled to the baseboard, and allowing it to pivot. This screw is placed 12" from the tip of the cutter, to cut a 12" radius block.
	This shows a short block held in the guide rails which keep your radius block square to the direction of cut. A little care is needed to keep this at 90 degrees to the surface it's mounted on, which will keep the block regular and straight. My jig was mounted on a WorkMate, so the block was able to protrude between the two sides of the WorkMate top, so my only limit lengthwise was the gap between the WorkMate top and the floor - 3 foot radius block anyone?
Here it is - a radius block, with 120 grit taped on, and a stripe ebony fingerboard freshly radiused...

How it works.

By now the operation of the jig should be pretty clear.

Clamp your squared up block in the rails, and taking narrow passes swing the router on it's pivot so it cuts a radius into the face of the block.

Lower the block, re-clamp and repeat until you're happy with the length achieved. I recommend you power off the router between each pass to avoid any risk of encountering the cutter whilst adjusting the blocks height.

Some light sanding may be required to blend the cutter marks on the block, though it should be *very* light if your jig was setup well. That's it - simple as hell.