Photos from Nick Crumpton of Crumpton Cycles. Closeup after the break. If you think you know what this is, post your answer in the ‘comments’ section– the correct answer will be posted there on Tuesday!

To send in your own Mystery Pic to be considered for the Monday feature, click here and attach your photo with all pertinent information.

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  1. It’s hard to judge scale etc but it looks like the arm minus the spring from one of the after-market derraileur tensioners. Hole in bar allows you to trap the arm between hub and dropout, spring attaches to rear of the mech cage to add tension.

    • Answer from Nick at Crumpton Cycles: It is a tool from the late ’80’s/early ’90’s for slotting the spoke holes in hubs to accept the fat blades aero spokes of the day. Basically a drill guide to be used with 1/16th” drill bits and a hand drill.

What do you think?