VERTEX 3900-2352 Flange for 6" and 8" Rotary Table, Fits 5" 3 Jaw Chuck

This was a huge waste of money and time. The bolts for the related Vertex 6" chuck are M8. The mounting holes are M10. I went to the the cost, time, and effort to drill the holes out (using the 8" Vertex rotary table, which this item fits fine) to M12 and fit threaded steel M12-to-M8 sleeves. It turns out the holes aren't only the wrong size, they're at the wrong bolt circle diameter. I've always thought well of Vertex products, and generally they have served me well. But this was ridiculous. There's not enough space on the table to drill three new holes, so I'll have to make tools to measure the bolt-circle diameter then make my own backplate from scratch.