Anyone know what this key was for?

Measures about 3” by 3”. Just a square female end
TIA, Bryan

 

Roller skates? That looks like a bicycle on the top.

 

I think it's no old skate key too

 

I thought it was big for skate key

 

Looks like a logo, maybe TGC, or something similar?

 

Please show the hole end.

 

Maybe you could ask GTC Bikes.

https://www.facebook.com/gtc.bike.77

http://gtcmanufacturing.com/index.aspx

 

3 inches is a mighty long skate key

I see GEC Gas and Electric Co?

 

Yep, me too! Gotta be an old gas key, for a fireplace maybe.

 

GTC could be General Time Corporation, parent company of Seth Thomas. It does look just like some Seth Thomas keys.
I agree though, the logo does look like some kind of cycle.

 

I don't think that is a "T"

 

Well, there goes my strange bed wrench idea......which was a stretch, I admit!!!

 

In my workshop I have about 50 square keys which I don't know for what they are made, the mark on yours can help if we know the country of origin, do you have found it in a french or english speaking country?
Is can be made for a mechanic toy?
It seems to be more a rewinding key that a purge or other worksop use in my opinion.

 

Toy key makes the most sense even though it is big this estate in Ohio was a major toy collector his family was from Germany had antique toys from Germany and USA. And I mean tons