Another what is this

[Olderisbetter]

In a box of tools

 

[droopsnoot]

Is this some sort of pull-start or kick-start gear?

 

[brightspark]

a shagged out sprocket that someones modified

 

[Dozzer]

42 tooth sprocket, for .404 chain with bad dental hygiene.
Honestly don’t know but will be interesting to find out.
Edit, only time i can think of seeing stuff like this is on combines & planters where an interrupted drive may come in handy, but wild guess.

 

[BrokenBiker]

i would hazard a guess and say its possibly been modified by a previous owner for use as something other than a sprocket? no idea what but after searching both stamped numbers, nothing of any relevance comes up and google lens doenst show anything either

 

[Puglet1]

Is it a sprocket designed for going over an evenly spaced box / ribbed section of a conveyor?

 

[brightspark]

possibly a sliding coupling with 3 dogs engaging in to it

 

[Agroshield]

...with bad dental hygiene.

It may be bad, but look how perfectly symmetrical it is.

 

[zzr1200]

There are no fixing holes and no internal splines to transmit power.

I would suggest that the sprocket is slid onto a drive flange/hub with 3 drive dogs which might include guide or retaining outside ridges (to locate on the inside of the chain) to guide/retain the sprocket on the hub???

 

[colnerov]

The two holes around the centre suggests it's timed for engagement in a train of other parts.

 

[Morris]

Some sort of intermittent motion Geneva stylee?

 

[Migmac]

Could it be for a intermittent drive of some sort

 

[Bouledogue]

Edit, only time i can think of seeing stuff like this is on combines & planters where an interrupted drive may come in handy, but wild guess.

I'll bet you're getting close with this, @Dozzer . The interruptions in the sprocket would be very helpful in an extremely dirty environment.

 

[julianthegypsy]

42 tooth sprocket, for .404 chain with bad dental hygiene.
Honestly don’t know but will be interesting to find out.
Edit, only time i can think of seeing stuff like this is on combines & planters where an interrupted drive may come in handy, but wild guess.

Good guess, but I've overhauled more combines and planters than I care to remember and never seen anything like it. I like the conveyor idea with gaps for the bars, but again, never seen one like that.

 

[Pigeon_Droppings2]

Is it a cutter of some description...some sort of metal or wood cutter maybe.

 

[bricol]

As already suggested - it originally was a 42T 1/2" pitch flat chainwheel (ie typeA) - as described by the 08A42.

The A78404 looks to be the same style of marking, so done by the chainwheel manufacturer?