When I glue the two together I put a short piece of 3/16 dowel in the hole to add strength and alignment, and then clamp.
The other two (2) blocks of the same dimensions are used for the support to the table top. The ‘support block’ has a ¼ inch hole ½ inch from the top, centered side to side, and drilled all the way through. On the table saw I set the height of the blade to 1 inch and the fence should be 3/16 from the blade.
By placing the block upside down with the 1 inch top on the table saw and sliding it very carefully, I am able to cut a grove in both blocks. I move the fence away from the blade about 1/8 inch and do the same again. This will repeat until I have a grove that is slightly over 5/16 wide.
Thanks for looking and tell your friends.....