Where to buy a metal semi-cylinder for rocking experiments

[sdefresco]

TL;DR

I'm unsure where I might find such an object for the precision I'm looking for. Ideally, it'd come with known dimensions (density, mass, length-dimensions, etc).

I want to replicate the rocking semi-cylinder problem from analytic mechanics, but don't actually have in my possession a nice, solid cylinder to rock. I imagine my professor likely made his, or found it somewhere in Estonia. If anyone can point me to place where I might be able to find one for purchase, that would be nice.

 

[ChemAir]

I would suggest contacting a machine shop that does shaft work. They should have precision shaft material that can be cut to length and split. The key will be what tolerances you can work with.

 

[Asymptotic]

Search for "half round bar". For example, https://www.mcmaster.com/half-rounds
You might have success finding something off-the-shelf depending on dimensions and precision required.