Armstrong FA-51 Ratchet

[FrankLee]

What is the purpose of the unusual drive end on this Armstrong ratchet? It appears that the 3/8 square driver may be removeable, but I can't get the pin to move and I don't want to force it.

Obvious Plomb clone and really nice.

Anyone have a clue?

[lbgradwell]

I don't know, but my FA-51 has a normal drive...

[Papaw]

Is it a double reverse? What happens when you push the pin?

[FrankLee]

I tried pushing it, but it wouldn't budge. Maybe I'll try a LFH. 

[rusty]

Odd, not all FA-51's have that ring and pin, perhaps a special application, the ratchet is early war era for the most part...

(It is possible the pin isn't supposed to move, but locks into something attached to the ratchet (like the valve adjusting tools have a piece that turns and a piece that doesn't)

[FrankLee]

The LFH did nothing; not going to attempt a BFH. I suppose the pin could be there for something to lock on. The collar with the pin seems to be part of the gear, ie, it rotates with the gear/square drive. I dunno.?.? 

[Lewill2]

Does the pin rotate? Can you pull the pin to release the drive lug?

[FrankLee]

Does the pin rotate? Can you pull the pin to release the drive lug?

The pin does not move relative to the collar. It does not appear to move from side to side. I tapped it with a small hammer and it did not move. I have not tried to tap it out from the flush end.

[scottg]

Never saw anything like this!
I can't even see how the drive plug could disassemble from the backing plate.
 
Something makes me suspect military though, maybe aviation?
Emergency hand driver for landing gear or something?
  yours Scott

[J.A.F.E.]

I can't help on the drive plug part but Plomb made the ratchet.