Cheap Scrap and Muffler Clamps
The baseplate of this mount is made from 3/4" plywood, you could just as well use MDF if that's what you have on hand. The clamps are 2-1/2" muffler clamps purchased for about US$2.50 apiece. The microCarve Z-Axis has two bolt hole patterns in it, I'm using the K2cnc-compatible bolt holes here, since those are the ones you can get access to when the router body is in place. I also have a pair of rubber bands around the body under the clamps to prevent slipping. They were cut out of an old bicycle inner tube. To get a closer look, see the full size image.
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The only tricky bit is the hole placement on the base plate. I started with a 4" x 6" design, but ended up with a 4" x 4" design that I like better. See the full size drawing for dimensions.