Friday, October 2, 2009
Pole seats and altitude bearings completed
After purchasing some threaded inserts, I installed them in the pole blocks along with a handle with a threaded 1/4X20 stud attached. The inserts tend to pucker the wood around the hole, so I beveled the edge around them to prevent that without complete success. In between the wedge and the rest of the block I inserted a spring. The pole seats are not completed and attached to the upper cage.
After searching for suitable Formica, I obtained a large piece from a local cabinet supply shop. I cut two 1 1/2-inch wide strips and coated the back side and the outer edge of the altitude bearings twice with contact cement, then pressed the Formica into position. A router with a trim bit and a cloth soaked in acetone removed excess contact cement and Formica.
To attach the bearings to the mirror box, I had originally planned to use threaded inserts entirely, but given the trouble I had inserting them into the pole seats, I will only use them where I cannot simply use a nut and washer. I counter sinked each hole throughly, then used a block of wood with a piece of all-thread through it to insert the threaded inserts. That allowed me to ensure they are going in straight, and a dab of marine epoxy glue will ensure they will not loosen.