Finishing Bowl Bottoms on a Lathe

One of my favorite ways to turn a bowl is to start with it upside down on a lathe, work on the bottom of it, then turn it around, holding this tenon in a four jaw chuck, and complete the interior. That gets us to where this bowl is, which is completely turned, sanded, and finished. The only problem we have is we're left with that tenon here on the bottom of the bowl. We wanna look at ways to get rid of that, and that's what I wanna talk about today. What we need is a way to firmly but gently grip the rim of the bowl so that we can go back to mounting it upside down and get rid of that tenon here on the bottom. And that's what devices like this are all about. In this case, what happens is that as I turn this, those two spirals in the plates work against each other. That changes the diameter of the buttons. They're gonna dial in up against the rim of the bowl. Then there's another tightening step where I'll tighten the wingnut on the back. That compresses the rubber, holds everything really firmly in place. So let's look at how this actually works getting it on the machine. My four jaw chuck stays on. And the jaws of the chuck will grip the plate on the back of this plate. So first step, we dial the diameter in, just using those spirals working against each other. Then we start doing some hand-tightening here. That does a great job of gripping the bowl, allowing me to do some more machining here, but let me show you another great tip. This is about finessing the bottom and cleaning it up, not hogging off a bunch of wood. But what we can do to allow a little bit more aggressive cut and make sure that the bowl stays in place here on the chuck is to buy a little insurance with this wooden ball. Now, here's how it works. I wanna use my tailstock. But I don't want the center that's typically here in a live center to penetrate the bottom of the bowl 'cause that's absolutely counterproductive. I'm going and putting another mark here in the bottom when I'm trying to eliminate marks from the bottom. So I've taken the center out of the live center. That leaves behind a cup. This wooden ball goes in the cup and then goes against the bottom of the bowl. Now I can snug this up. Now, still, like I said, this is about finesse, not about hogging a lot of material off. But using the tailstock and that wooden ball, it's really a great tip, and it's a way to buy a little insurance and make sure that everything stays in place as we do our turning. Now that I'm set up, I can start working on that tenon on the bottom. Well, I think you're gonna agree, this looks so much better than what we had on the bottom of this bowl before. So jaws like provide a wonderful way of gripping the rim of the bowl, allowing you to provide a very professional look here on the bottom. All I need to do is a little bit of sanding, write my name, the type of wood, and the date. That's the message I like to leave on the bottom of the bowl. I can finish over that while it's still her one the lathe. And that bowl is completely done thanks to the chuck that allows me to grip the rim and finish the bottom.