Retractable Castors for a Mitre Saw

The mitre saw is a really useful tool but it needs a lot of space round it when it is being used.
It would be nice if I could easily move it to one side for storage when it's not in use. Castors would be good but the saw need to be immovable when in use. Enter the retractable castors.

I experimented with some corrugated card and came up with this linkage to lift and lower a set of castors.In the final version I used the same basic design but the other way up.

The final design uses two 50mm castors (from eBay) and five 75mm hinges at each end of the saw.Here's how the parts are joined together. The hinges are marked in red. the cross piece at the bottom is bolted to the legs with a couple of M6 x 70mm bolts. The linkages are made from some 3x1 I had laying around.

While I was assembling the parts I raised the stand 25mm on some blocks and shims.

Here are the various bars and linkages all joined together. You can see the wood block screwed to the inside top of the stand where the upper hinge is fastened.

A 1mm stiff steel wire is used to make a catch to hold the bars into position. It is fitting into a couple of drilled holes in the upright. A couple of notches keep it in position.

Here are the retractable castors in action.