How I build a block rim

I was recently asked how I put together my block rims. As I was writing the email to explain my process, I decided instead to post it to my web page. So here goes.

I first cut 8 blocks per layer (sometimes 3, sometimes 4 layers) at 22 1/2 degree angle cuts. For a 12" rim each block should be 5 1/4 inches long and 1 11/16 inches wide. It's very important that each block is exactly the same size and that all the angles are exactly 22 1/2 degrees.

With all that said, it is almost impossible (for me at least) to get each block exactly the same size and exactly 22 1/2 degrees. So, this is my process:

I make half layers (four block) at a time - below you see four half layers.
I first lay out my blocks on a flat surface and prepare them for gluing.
One block per half is clamped down for stability

I then cut up 24 short peices of electrical tape in preparation for the gluing.

With one block clamped down, I begin gluing each piece together.
I then use the electrical tape (any stretchy tape will do) to keep the block tight.
(You do not need 200 lbs of clamping pressure to get a good solid joint.
This stretchy tape works just fine.)

Here are two layerers glued up (4 halves).

Now that the layers are done drying, you can see that
the edges don't meet perfectly to make a perfect joint
(it's only about 1/32 in off, but that's way too much)

This is where the edge sander comes in. This machine allows me to put a
perfectly flat edge on the end of each half.Another view of the edge sander.
Now I have four new flat edges and two perfect joints.
Another advantage of building in half layers, is that I
can get the interior to the band saw before each layer is glued together.
Here, I first draw the interior curve on the layer.

After I've completed to halves you can see the interior is a pretty decent circle.

Now its time to draw a curve on the exterior of each half.

Now its really starting to look like the layer of a banjo rim.
These two halves are ready t o be glued together
using the stretchy tape method.

After quite a bit of surface sanding and flattening (again on the edge sander),
I stack each layer and glue them together.

Another view.

In another day, or two, this rim will be ready for the lathe.