Hi Tom:
Welcome to the forum. I hope you visit often, and enjoy your visits.
BTW, is there any chance that the maker of your G'father's plane is spelled with a G instead of a C?
Found several hits on a Siegley No 5 planes. Even several up on Ebay.
Found one Siegley 8-C from 1900, looks to be a jointer's plane about 20 to 22 inches long. Metal body with wood knob; kind with out blade depth adjusment (bang on front to expose more blade, rear to less blade.)
Phil |