My process when I'm making lids involves two basic steps. First, mount a blank in a four jaw chuck, drill for the lid and fit it. However many I'm making I will do this step to all of them. When they are all drilled, they get flipped around and all the finish cuts and sanding are done. I discovered early on a four jaw chuck wouldn't work for the second step. There is no room for tooling and it puts my fingers too close to the spinning chuck.

 

 

My solution was to make a wooden expansive chuck. That actually worked really well and I've been using it for years. It uses the same principle as a four jaw chuck with all four sections expanding. I also discovered it would not work well for the current size lids I'm making, there isn't a lot of material and it's easy to split the short grain on the lids, so back to the drawing board. I decided to make another wooden chuck that only expands to two directions, that way I don't have to put any pressure on the weakest part of the lid.

 

 

The first step was to mount a piece of maple in my four jaw chuck and drill and tap it with a spindle tap. I like a spindle tap because the chuck, waste block, or whatever can installed and removed over and over again and it will still run true. That's not always the case when mounting in a four jaw chuck.

 

 

After tapping I always soak the threads with super glue and then retap them.

 

 

Just screws right on!

 

 

The line is in no particular spot but it will help me when I split the chuck at the band saw. The chuck is turned to roughly finish shape in this picture.

 

 

My spreader is attached to a 3/8" threaded rod. It's tapered and just over 3/4" diameter at the end. The jaws have been drilled with a 3/4" through hole.

 

 

After drilling the chuck and fitting the spreader it's time to split the chuck. It's important the saw kerf is as near center as possible.

After cutting the saw kerf the piece gets remounted and the chuck gets turned so a lid will just fit over the end.

 

 

For new turners. I know sometimes it seems as though you'll never stop making silly mistakes. The simple truth is, don't worry, you won't!   I got the "clamp" area a little too small but thought I could make it work so I really tightened the spreader. Heard a crack and I had split my chuck. Had to make a detour to the drill press and glue in a couple dowels cross grain to save it.

 

 

Making the clamping surface too small isn't as big a deal as  a person might think. It's a simple matter to glue on a new wood and try again. The first chuck I made has been "resized" many times.

 

 

And here is why I go to the trouble to make one of these. If I'm careful to position the lid correctly there is zero pressure on the weak short grain section. I also have lots of room for tooling with no gaps or spaces to get a finger  dinged up.

 

 

 

Cool! But I have a question. How does the tapered expansion plug get tightened with the lid in place? Is it a drawbar configuration?

That's about

 

1 hour ago, lew said:

Cool! But I have a question. How does the tapered expansion plug get tightened with the lid in place? Is it a drawbar configuration?

 

LOL, Sorry Lew. All those pictures and I left out one of the most basic pieces of information. Yes, the 3/8" rod extends through the head stock like a draw bar.

 

That is as Dan said One Cool Idea