Fri Apr 6 2007

Drilling wing conduit holes

After getting the drill press reassembled (with new bearings), I started using a unibit to drill the conduit holes. But after drilling 4 or 5 of them, I learned that the unibit was drifting. The problem is that I couldn't hold the rib down tightly enough by hand to keep it from moving around. Here you can see two of the conduit holes are off by about 1/16 inch. Arghhhh! Unibits suck!

So I manufactured some clamp bars from some old oak flooring. Here's how the process works...

Install drill bit in chuck and use it to locate the rib directly under the chuck on the table.

Then assemble the clamp bars and tighten them down. Now the rib is held firmly in place.

Take the drill bit out and install the unibit.

Run the unibit through the hole to get the required 7/8" conduit, hole. Remove the clamp bars, rinse, repeat. This process worked great and I didn't have any more trouble with the holes drifting, but it was very time consuming. I probably spent three hours drilling the remaining 21 freakin' holes.