This is the opposite end and this had 7/16-20 threads in it. I won't be able to use them for this project but I did have to use an extra long center drill to reach the bottom of the hole. Notice the longer one next to a standard length one to the right. Once I was all finished drilling, the mismatch in the middle was minimal so this worked out great. All this so a wire will pass through it.
 

Drilling and Tapping

Now it's time to start thinking about attaching things, like a base to have it sit on along with some lamp hardware. And being that this cam is pretty soft, I can drill and tap some holes without any problems. Speaking of holes, the two that you see on either side of center were in the cam when I bought it. As luck would have it, they were exactly the right size for 3/8-24 threads.

What I decided to do was drill and tap this thread size in four places, not just the two that you see below. But to use these existing holes I would need to know what 'bolt circle' or radius they were on. Once I figured that out I used my indicator to find center, then using my indicator again, I aligned the two existing holes so they were parallel to the Y axis. Once everything was in alignment I drilled the other two holes and then I tapped them all with some 3/8 fine threads. I decided to use this end for the top but with these holes being so close together, I don't think I can use hex bolts because the heads will touch each other. Don't worry, I have a plan.
 

The opposite end will be used for the bottom or base. And as you can see I've drilled and tapped three 5/16-18 holes. I split the difference between the outer diameter and the spud in the center for these new holes. The smaller hole at 12 o'clock had the dowel pin in it and I won't be using it.
 

I started thinking about how I was going to make my adapter for this end and decided to make it easy on myself so I removed the boss (spud) completely (see the picture above if you don't remember). While I was getting close to the bottom surface I started taking lighter cuts, only to find that this end wasn't square with the surface that I'm holding on (cam journal). Notice the plating that didn't clean up on the left side. This is how I knew this surface wasn't square with the remainder of the cam. No I didn't leave it like this, I took this picture before I made another cut so the entire surface was cleaned up.
 

The Base & Adapters

Here are some gears that I'll be using for this project. Speaking of gears, my daughter Tracey, brought over a bunch of gears awhile back to be used for another project. However, I only used 'one' gear up to this point, and that was for her lamp project.

I went through all the remaining gears and this was the biggest one I could find, which will be used as the base. It's about 4" in diameter and should fine for what I'm making. The smaller one will be used as eye candy. In other words, the smaller one won't be functional, it's just to look cool.
 

I'm making all the adapters out of aluminum and this one will be used at the bottom. That spud is sticking out .100" and will locate the smaller gear, which I'll show you in a minute. The thread in the center is 3/8-16 and will be used to hold the base together (large gear).
 

Notice the screw heads have been turned down. This was necessary because of clearance issues between the spud and outer diameter of the adapter. All I did was put the screws in my lathe and took a few cuts till I had what I wanted.