Thought it was a toy badge at first

[Barrydang]

Thought it was an old toy badge at first but it has a big hole in it.

 

[flip flop]

Looks like an old bicycle chain gear

 

[Kray Gelder]

Faucet/valve handle?

 

[A2coins]

Not a bike sprocket I think valve handle as well if it is a bike sprocket the chain would have to be pretty big

 

[ToddsPoint]

That gear is pretty old and took the old style chain. Early 1900's. It would be the bottom chain pictured. The top chain type was used up until WW2 and was called a skip-tooth. Used before WW2 mainly. Gary

 

[Toecutter]

Skip-tooth sprocket boys!! Todd knows whats up

 

[Tony in SC]

I thought sprocket, but I'll go with rusted out center for a planter disc?

 

[pganjon]

What about a spark plug gap gauge? Paul