Heavy brass, have no idea what it belong to. Any ideas?

Brass, or more likely Bronze because it's harder, tools are used for Non sparking applications, like oil rigs, refineries etc. Although that hole with the washer/bolt marks looks like it's likely part of some kind of machine. A wheel with a pin would turn, causing the pin to slide in the slot, making the handle part waggle back and forth as an actuator for something else. Any names or markings on it?

I believe it's a brass spanner wrench.

Keith

I agree with BigBob. It's part of a machine. A lever of some kind.

No names nor markings. Thanks for your input. Dang wealth of knowledge on here.

I agree it is a machine part also.

Bronze age pig castrator

given the taper I would suspect dual purpose each end gets used a tool for some sort of machine that uses tapered shafts and that it used to drive out the tapered shafts , turn something possibly while lining up gears

the other slotted end and brass or bronze so non sparking almost makes me think gas valve turn off wrench but both ends I think would have a use given they seem intentional

thats all I have

It's a non-sparking Drum Plug Wrench

Looks like a pivot hole, maybe an indicator needle or shifter of some sort.

It’s a works wrench. Used in an emergency. All you do is throw it in and everything stops.

Truth