Quite perplexed on this one. I have no idea what this could be.

[drachetanzer]

This was found while metal detecting the yard of a house built in 1906.

Any ideas?

 

[Crispin]

looks like a dial that would pop into another piece

 

[G.I.B.]

I was thinking more like an old vintage rosette for furniture perhaps...

 

[ecmo]

If there's traces of threads around the stem than I'd say a leveling foot for a kitchen range or washing machine or dryer.

 

[ARC]

Oil lamp / lantern wick advance wheel / tender knob ?

 

[Bruce R]

Looks like the male half of a heavy duty snap assembly, the female half, or socket, would've been spring loaded.

 

[DCMatt]

To me it looks like a piston from a hydraulic cylinder - like a wheel cylinder or master cylinder.