What is this tool do?

I got this tool when i bought out an old truck repair shop. Looks to be in good shape. But i don't have a clue what it's used for. Please enlighten me.

 

Maybe used to split a case of some type?

 

Looks like an old time tool for piston ring grooves.

 

The handle says "Simplex Grooving Tool", contact Simplex and find out.

 

Makes sense to me!

 

Probably a thread chaser for a floating axle. Use to clean up the threads after a lock nut failure. Looks like it would fit large and small axle ends....

 

Yup.

 

I think that BamaMav got it ,what are all the little parts around the edge of the case. are they cutting bits.

 

Its for circumcisions. It adjusts from my size, all the way down to your size.

 

Simplex made piston rings pre war mostly, theres alot of cool old ads you can find from them. They advertised for the do-it-yourself-er to replace your own rings!
My best guess would be its a groove cutter and cleaner, universal for all pistons.

 

cleatus! Do you know where the "time out chair is?" I think you just earned a seat.