It’s in the chapter on building a Horizontal Routing System and consists of two rectangular blocks, each with a semicircle cut out of it.
The blocks are connected by a hinge at one end and a bolt at the other, which tightens their grip on the body of the router.
(The photo above is from the book and will be replaced with one of my own once I have made one myself)
Like the yellow one shown in the book, my combination router has the motor in a cylindrical section which locates into whichever base I want to use (plunge or fixed) and this section is ideal for the clamp outlined above as it won’t obstruct any of the vents.
(The router, sometimes known as the 45368, is available from Yandles at the moment for £99.99, which is such a good deal that my Dad and I bought one each, so I now have 2!)
I think a circle cutting base for my router is the best way to make this clamp, but although I have the perspex to make such a base, many of the plans I’ve seen require the use of a router table to cut the slots used to make the jig/base adjustable, which introduces a rather Catch-22 situation …
I’ll see what I can do with a guide clamp