Well found my answer at the begining of this post in 2008,, where full pictures are shown, its used to be on the back side righ tunder where my part number LBS-26 is,, I can only see 2 little rivets head, had to pass my finger over them to realise they were there, 3 3/4 center apart, so it makes my saw a third style tag, that began late 47, too bad that there is not a ghost image of the serial to pin point its origin or date of production, although LBS-26 on a manual dates 11-15-65 item number 426-02-651-0002 from power tool division rockwell international. So that upper arm may have been used in many models since I saw tha upper arm number also in a manual dated 1950 for same type metal , metal / wood bandsaw. Will keep reading. ;) very interresting subject.
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