I had this cut on a milling machine and it is as square as I can tell. Not temp sensitive, doesn't move if it's dropped.
Home brewed feather board.
Jig for cutting narrow pices one after 'tother and all the same size.
Modified mitre fence with adjustable stop.
Cross cut sled.
And again.
Home brewed tenoning jig.
And again.
Tapering jig.
My mitre jig is currently in pieces being upgraded to the MK 2!
Roy.