What is this tool called?

[<me9]

They have been used from the year dot. Saws inherited from (at youngest) my father used them, and are probably at least a hundred years old.

[Tim Watts]

[e-mail] ( [e-mail]) wibbled on Wednesday 09 March 2011 11:35:

Some cheap argos fan heaters from 2 years ago had some...

[PeterC]

Mine (modded a 'driver) is for doing up the nipples when building bicycle wheels. It's for the stage where the tensioning is just beginning but not worth using the spoke key and the notch allows for the end of the spoke protruding in to the slot - it shouldn't protrude but sometimes the spokes aren't to the exact length.

[Graeme]

So close! Yes, railways, and yes, axle nuts, but sadly the Romford tool is too small. I need a larger one, for the nuts on a (Meccano) Hornby 0 gauge loco, from the 30s.