I mark the bottom side of the top circle I just chose. Why the bottom? Because you won’t see it once it’s assembled.
Time to see if my plan to mount the bearing between the two circles will work. This is the part that I had to figure out in my head while at Lowes. I had to make sure it was going to be physically possible before buying the materials.
Fist I’ll mount the bearing to the underside of the top circle. Here the top circle is clamped down to the table and we are looking at the underside with the bearing roughly centered.
I was not sure how I was going to center the bearing perfectly. But I figured if I had a truly perfect circle the corners should be the same distance from the circle’s edge. I also figured that if I screwed up I could just move the bearing and try again since this surface is hidden.
I get to used another fun tool. A set of digital calipers. This allows me to measure each corner and adjust until they are the same distance from the circle’s edge.
Once I’m sure the bearing is centered I clamp down two comers to keep things in place.
Now I can screw down the other two comers while everything stays centered.
1st I made an indention in the center of the mounting hole with my trusty hand drill.
The indention helps guide a small drill bit for the srcew pilot hole. Only drill about half way into the wood. If you don’t trust yourself you can mark the drill bit depth with a piece of tape so you don’t drill to far and come out the other side.
The pilot hole helps the screw go in straight. It also prevents the wood from splitting.
Here’s the top plate of the bearing all screwed in.
Now that the top plate is mounted I need to make access holes in the bottom circle so I can screw this thing together with the bearing sandwiched between the circles.
Before you say WHAT? You are making holes in that nice piece of wood? Keep in mind this is the bottom and eventually the holes are going to be covered anyway with some kind of anti-skid material (most likely some kind of cork shelf liner). And the holes are necessary for the final assembly.
I start by centering the bearing again (this time the bottom circle) and marking the centers with my hand drill.
Next it’s over to the drill press to drill small pilot holes for the larger access holes. When possible I like to drill pilot holes 1st. They are easier to initially drill though the wood. And the also guild the larger bit as it bores through. Making the holes come out straighter.
Here the larger access hole is being drilled. A 1/2” hole should allow for enough room (if everything lines up nice).
With all 4 holes drilled I place the 2 circles together. Whew, The access holes line up perfect!