Help trying to ID mystery item

[michael NY]

I dug this along with a few coins on the edge of a lake most of the coins are all early 1900s the area has see lots of action connected to an iron ore mine to a Boy Scout camp. An old homested. I have pulled Reveloutionary War Musketballs also from the surronding area.
The item is brass top edge to edge is 1" 1/4 . has female threaded depth of 1".
My first thoughts were possible radiator cap or even a fuel cap. its nice machined work. I've NEVER seen any kind of power boats on this lake. lots of swimming fishing camping.
I have found an old set of ice tongs gave to a friend. please feel free to ask anything i van hbe more helpfully with. Thanks for looking

Michael

 

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[TreasureCatto]

Water valve cap/fitting?

 

[desertexplorer]

Your find is an old antique grease cup cap. They were used on engines, tractors, automobiles and farm equipment and came in an assortment of sizes and shapes. Yours has a notch in it for a safety catch that had to be pushed down to screw in to force grease into the unit. The notch kept it from vibrating and unscrewing itself off and getting lost (doesn’t look like it work very well!)

 

[Terry Soloman]

Your find is an old antique grease cup cap. They were used on engines, tractors, automobiles and farm equipment and came in an assortment of sizes and shapes. Yours has a notch in it for a safety catch that had to be pushed down to screw in to force grease into the unit. The notch kept it from vibrating and unscrewing itself off and getting lost (doesn’t look like it work very well!)View attachment 1860080View attachment 1860081

Super I.D.!!!

 

[michael NY]

Thank you!! something i would have never guessed. funny I'm familiar with a modern auto luber used on machinery bearings basically same idea. thanks again!

 

[DCMatt]

Excellent ID!

My 1948 Chevrolet Fleetmaster has a similar cap to lubricate the distributor shaft. It is filled with heavy grease and every few hundred miles I reach in and give it a half turn. Crude but effective.

 

[Tony in SC]

They're all over a hit & miss engine!!

Your find is an old antique grease cup cap. They were used on engines, tractors, automobiles and farm equipment and came in an assortment of sizes and shapes. Yours has a notch in it for a safety catch that had to be pushed down to screw in to force grease into the unit. The notch kept it from vibrating and unscrewing itself off and getting lost (doesn’t look like it work very well!)View attachment 1860080View attachment 1860081