12 years ago
I have a Fein "Multimaster". It's an electric hand tool with various
"blades". For sawing, sanding, cutting. It works by vibrating very
fast & with very small displacement.
The various blades have this mounting hole:
The "points" on the hole do not engage anything on the tool - the blade
is free to be rotated to any position & then fixed in place by
tightening a screw. I.e., it's fixed by friction.
Why, then, does the hole have those points?