I have a single Evinrude thumbscrew with cast aluminum handle. Handle has Evinrude embossed on the sides of the handle. Fine thread screw. Never used - takes the stamped steel round cup pad, held on by distorting the tip of the screw. I do not have the pad. OEM part number is 276638. I believe these were used on Speeditwins, Speedifours and Big Fours of the immediate pre-WWII and post WWII eras. Asking $20.00, postage included.
Can send jpeg pics upon request.
PM or E-mail: csr112-n AT twcny DOT rr DOT com