Fabulous set of chasers. I have never seen this style before. Based on limited research these may have been manufactured for or by Pratt & Whitney who were based in Hartford. Here are the sizes in P. I. : 7 & 9 (straight cut), and 9 (side) WHIT (Whitworth?) and 7 & 9 (straight), 7 & 9 (side cut), and 13 (Side) N. S.
I see absolutely no damage to any of these. Extra fine condition.