Can anyone identify this...tool?

[Knive]

Got this in a lot I picked up today. No idea. Looks to be stamped RP on the bottom.... but maybe personal initials. 3" tall.... step goes from 1/4 to 1 1/8.
Any info appreciated!

 

[pedalwrench]

Tells you what i.d. a tube is?

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[gatlibs]

Are there separate discs that come apart?

 

[dsgreen3]

They look like Oring gauges to me.

 

[Millwrong]

Looks like something a kid would make in a high school machine shop class to me. A nice simple lathe project to demonstrate that you can turn a variety of diameters accurately.

 

[Legion Prime]

Looks like something a kid would make in a high school machine shop class to me. A nice simple lathe project to demonstrate that you can turn a variety of diameters accurately.

My first thought as well

 

[gorilla]

Home made bushing driver?