I finally found myself a worm drive skilsaw here in Australia, they’re rare as hen’s teeth here but having used one years ago I knew they were great tools, and have finally found one. My question is Does the inner collar always look like this? It looks like someone has machined it off, but not sure. And do they have a matching collar for the outside? As is normal to prevent blade twist and wobble. I suspect this one has been lost as it seems to have a couple of washers in place which aren’t very true.