These white Flap Bearing Blocks need 2 holes that match holes already punched in the side channels. I was ging to use the drill press for this but I was afraid that the drill press would not drill a straight hole. So, again I used the lathe. Its precise and drilled prefect holes.
The plans say to drill thes guys out with a #10 bit to recieve a AN3 bolt. So, I drilled the holes in the side channels to a number 10 as well. Interesting in that the AN3 bolt shank does not fit through a hole in aluminum made by a #10 drill, but the threads do. That's all we need. The shank will be in the block and only the threads will go through the side channels. A #10 hole through the nylon blocks makes a nice tight snug fit. You can see why I wanted to use the lathe, all these tight fitting holes.
1.) I marked the hole locations on the bearing block on the side that fits against the side channels. I'll drill from that side. 2.) Using the lathe and a 3/16" Plexi Glass drill bit I drilled one hole. I drilled at very slow speed. Worked the bit in and out. It wanted to grab a bit. 3.) Ream out the hole in the bering block to a #10. Easy, clamp and use a normal #10 drill bit to ream it out. Watch out. It wants to grab. 4.) Mount the block in position on the side channel with one bolt and match drill by free hand a starter hole in the bearing block. I went about 3/16" deep. 5.) Move the 3/16" drill and bearing block back to the lathe to finish the hole. To get the bearing block positioned I stuck the drill in the bearing block starter hole and clamped. Back it off, turn it on and drill. 6.) Ream out this second hole to a #10 as you did on the first hole.
I got these holes in perfect position. The 2 bolts fit through the block and then through the side channel holes perfectly. Wow, came out great. Very close tolerences here.
