When Dad died at 84 I got his Craftsman circular saw. Had the 1953 original sales ticket in an envelope in the metal case. And a brand new never used 6-tooth carbide blade that came with the saw according to the sales promo also in the envelope. He used the beejeebers out of that saw every place they lived. And took care of it too. Built a lot of church / scouting / volunteer group structures. Mother said he never used that blade because he knew it didn't have enough teeth to be any good. Don't know when carbide saw blades first appeared but suspect this one was early-on. Memories... /s/ Stubby