Where does this go?

[Steverat]

It’s part of a 1951 plunger A10 but I can’t remember where and I’ve nearly finished the rebuild. Any ideas?

[Greybeard]

I can't place it. Might it be for the toolbox?

[morris]

Homemade brake pedal stop?

[Simon59]

I've recently finished stripping an entire 1954 A10 plunger and I definitely haven't come across that bit... so don't worry? 

[duTch]

 Looks like a stubby holder-holder

[Greybeard]

Maybe the horn was mounted on it.

[gt6uk]

With the corner having a radius it looks like it was made from a piece of angle so i doubt it is original.

Steve

[Steverat]

It feels like a properly finished part to me, the radii are all smooth and symmetrical, not hand filed.

[scotty]

Does it have something to do with anchoring the fwd  end of the rear mudguard to the frame ?

[Steverat]

There are two struts for that

[berger]

it looks like one hole is elongated --- chain guard or something that needs a bit of lining up my brake light switch bracket has one similar but I made it that way

[berger]

steve I just went through the whole parts books for swing arm and plungy bikes , don't see anything like it anywhere 

[chaterlea25]

Hi All,
It used to be a "standard" practical joke to drop a random part or two that "looked right" into the parts boxes
when some poor bugger was rebuilding something complicated, 
A likely looking shim, odd looking bolt or screw could and would drive the victim nuts 
and often lead to 

John

[Peter in Aus]

I think John has got the answer!!

[lawnmowerman]

Looks like it was custom made from a piece of angle iron due to the radius inside the bend and the sharp outside corner. If it was made in the factory it would probably be a piece of bent flat which would look quite different.
The holes are different sizes too which may give a clue.

Jim