Mike’s 1985 book The Practice of Woodturning showed his chuck-plate invention. Some engineers scroll chucks at that time had two-piece jaws. The back halves of the jaws were toothed to engage with the scroll, and could thus be moved radially. Different designs of front half-jaws could be screwed onto the back half-jaws for non-standard gripping tasks. Mike was the first to utilize this two-piece-jaw facility in woodturning, by having steel sector-shaped chuck plates made which screwed onto the back half-jaws. Wood, plywood, or MDF sector-shaped plates could then be screwed onto the steel chuck plates. Circular grooves could then be turned into these plates, and bowls then gripped by their rims so that the chucking features could be turned off their bottoms.

An important advantage over the later Cole-type jaws is that because using chuck plates the bowl rim is compressed over its full perimeter, it can be highly compressed. This braces the bowl wall enabling the chucking features to be turned off very-thin-walled bowls. The system can also be used to grip by expansion

The components of the chuck plate invention

A diametrical section through a chuck showing outside gripping

Turning a recess whose outside diameter is the same as that of the bowl which is to have its chucking feature turned off

Mounting the bowl