A Rim Shaping Jig Utilizing a Horizonally-Mounted Router


I have created three different incarnations of this idea. They all have the same basic concept: a router mounted on a moving base that cuts the rim as it is turned on a spindle. My first was very simple. The one shown here was my most ambitious and includes accommodations for truing the bottom edge and adding inlay strips at the joints of block rims. I have put this articletogether hastily for the benefit of a seeker on a Yahoo group. I'll try to add details later.

This is a drawing of the base holding a laminate trimmer. A router will do the same job. The laminate trimmer is excellent because it has a fine adjustment wheel that helps you get an excellent fit for your tone ring. (Click on the images for a larger version.)
This is the side view of the spindle holding the rim on a face plate. The face plate is wood. You make it yourself. The spindle is a stock item sold by Woodcraft.
This is the front view of the spindle and faceplate. The laminate trimmer is shown in cutting position (minus the base holding it).
OK, this is a little complicated. I hope I can explain better in a future version of this article. The spindle assembly is at the bottom. The router assembly is at the top. The base of the entire jig has slots. The router base has runners. This lets you move the router as you turn the spindle holding the rim..
This shows the router assembly truing the bottom edge of the rim. The spindel assemby is rotated 90 degrees from the previous illustration.
Router bits that can be held in the router or laminate trimmer are not long enough to cut the whole inside of the rim. However, you can cut a very accurate rabbet in the end of the rim.
If you had started with a six sided block rim, this is how it would look from the front after you cut the rabbet.
If you have a shaper or a router table, you can use a very long flush-cutting bit. The bit cuts until the bearing encounters the rabbet. If the cutting surface cannot cut the whole height of the rim, you can do it in stages as long as the bearing is high enough to meet the rabbet. One downside of this method is that the bit is so long that you get some chatter.
An alternative to the shaper is a drill press and a sanding drum. Woodcraft sells the "RoboSander" is a sanding drum with a bearing on the bottom. The bearing allows you to sand flush to the rabbet. They sell a 3" diameter by 3" long model that is tall enough for most rims. The downside of this system is that you spend a long time sanding and creating dust and you will use up several sleeves.
  That's it in a nutshell. I have created three rims using this method.

December 16, 2003