It doesn't happen often, but when it does it's annoying and a bit scary.   I'm cutting something light and thin like a narrow strip of 1/4" plywood on my 1970 Delta/Rockwell wood cutting band saw and the little aluminum insert comes popping out of the table becuse of the vibration, gets snagged by the blade and flips out onto the floor.  Sometimes it goes into the blade and gets cut in half.  So, I've always kept a spare or two on hand.

Well, it happened again this morning so I got out my replacement, ready to install it:

It's pretty flimsy, just a 3/32" thick aluminum disc.  This time I was determined - finally - to upgrade my saw to a more stable and safe setup.

Looking around the shop, I found I had a nice fat slug of cold rolled steel.  Coincidentally, it was 2.500" in diameter, the same as my aluminum insert.  I chucked and indicated it in my 4-jaw:

After facing and turning it to fit the secondary recess in the table (2.250" diameter) I parted off my new piece:

Over on my metal cutting band saw, I held my disc down to the table with a push stick and against a temporary wood V-block slide to rough out the blade slot:

I made two cuts as close together as I could, with a tiny piece left in the middle.  The rough slot came out to about 1/8" wide.

I used my little Rusnok mill to plow a 5/32" wide notch:

Turning it 90 degrees, I plunged with a 1/8" mill to fit the indexing roll pin in the table:

Here's my finished insert:

With its half inch thickness, this thing weighs a lot compared to the original insert!

It's not a press fit, but it's so heavy it drops in and stays put.  In addition to the mass, its extra thickness means it would be unlikely to rise enough to jump out of the hole even if the saw vibrates quite a lot: