rivet or button

[private detector]

I found this button or rivet , don't know which. Any help would be great. I forgot to show size , it is 7/16 of an inch.

 

[doublet2a]

Maybe a type of date nail

Tim

 

[Back-of-the-boat]

Looks like a tack head

 

[nhbenz]

The size may make a difference in what it could be

 

[osage express]

Date Nail Info This might help .yours would be 1915

 

[CRUSADER]

We had lots of these before, I forgot what they are, maybe pole markers or railway related, look back on Tnet (do searches)

 

[FreeBirdTim]

I have something similar on the wood trim of my outdoor window frames. Mine are aluminum, though. They're used to ID window frames so you can match up storm windows to the correct window frame when you put them back in the fall.