Have you ever gone through the bottom of a bowl? I sure have!
Too frequently as a matter of fact, or I have removed the finished bowl from my vacuum chuck only to find the bottom thicker than I had wanted it to be.
To resolve this I decided to fabricate a Jig that would let me ‘see’ where the bottom is, no matter what type of chuck I use to do the final thicknessing and finishing of the bottom.
Here is a photo of what I came up with in use. The actual inside of the bottom of the bowl inside the chuck is indicted in this instance by the left side of the vertical arm.
I have posted more details on one of my web Blogs https://woodbowlsandthings.wordpress.com/
I hope you find it as useful as I have.