09-07-2022, 07:51 PM
I bought one of those coaxial centering indicators at least ten years ago from Little Machine Shop. Never used it until today. I'm sure glad that I had it because I had to center on a couple of holes I drilled in a piece of steel but I didn't have a reamer to ream to final size. The drill rod didn't fit the drilled holes so I had to enlarge them somehow. I tried setting them up in the 4-jaw chuck but since I hadn't squared the stock up, keyway stock, the holes weren't exactly at right angles to the adjacent sides. I looked into buying the proper reamers but 5/8" & 3/4" reamers are expensive. 
Time to christen the boring head. But alas, I did not have a boring bar that would fit it so I ordered one from McMaster. It arrived today so I used the coaxial centering indicator to center up on the holes and bored them out. I screwed up the first one because I forgot to lock the head after adjusting the height so the hole turned out a bit sloppy on the drill rod but I think it'll work. If not, I'll have to make a new one.
Ed
Time to christen the boring head. But alas, I did not have a boring bar that would fit it so I ordered one from McMaster. It arrived today so I used the coaxial centering indicator to center up on the holes and bored them out. I screwed up the first one because I forgot to lock the head after adjusting the height so the hole turned out a bit sloppy on the drill rod but I think it'll work. If not, I'll have to make a new one.
Ed