Saturday, May 16, 2015
Frame Bottom Plate Part 2
Once I had the circle cut then next step was to cut all the slots in the plate. I started with the 10 slots around the edge that hold the uprights. I was debating how best to cut these when I ran across this blog post that had a great idea for a jig to do this. Here is my version.
It took my three tries to get a working jig and the biggest thing I learned was the the original shape was unnecessary, a rectangular jig worked just fine.The jig is designed to be used with a router with a guide collar and a 1/2” bit.
The piece of wood you make the template from needs to be as thick if not a little thicker then the height of the guide collar so the collar doesn’t touch the piece you are cutting. I made the jig 12 1/4 inch long which was wide enough to get from the pivot point to a point where the router bit can get beyond the edge of the base plate. As for the width, it needs to be wide enough to allow you to clamp the template to the base plate and still leave enough room for the router to get between the clamps. For my setup 14” wide was sufficient.
Once the plywood for the jig was cut I drew a line down the center that I used to line up the pivot point at one end with the slot on the other end. The slot needs to be just wide enough to allow the guide collar to slide smoothly, but if you make it too wide you will end up with slots that are wider the 1/2 inch and then the uprights will not fit tightly. I did this by drilling four holes with a 5/8” bit and then filing the edges of the slot smooth. I ended up with a slot that was a little to wide and didn’t realize this until I had cut most of the slots on the base plate, so be sure to test your rig on a scrap piece before making your cuts.
Once the jig was complete I put a nail through the center hole of the base plate and into the pivot hole on the jig and positioned it so the slot was over the first notch on the pattern. All of these slots need to be 1/2” deep and you want to keep them as consistent as possible. If you can do it in one pass you will get the most consistent depth, just be sure to check the depth of your cut periodically to be sure nothing is slipping on the router.
I made my slots a little shorter then the template showed because I had planned to square them off. This ended up not working out well since it’s hard to chisel out the corners in plywood, so I ended up rounding the ends to the uprights a bit to get them to fit.