DIY Concentricity gage

[The Mechanic]

All it takes is a slab of steel, four hardened steel ball bearings and a piece of drill bit. Oh and your favorite mag base dial indicator.

 

[DCR]

Looks like you just jb welded the bearings in place?

 

[downrange67]

Nice job!

 

[The Mechanic]

holes are drilled to locate the bearings and while the epoxy sets up just flip it upside down so the bearings locate fully on a case then it won't "3 leg" on you. All the bearings are resting on the case with equal pressure.

 

[shooter.dm]

Thats not a bad idea with the balls

 

[DroidSniper]

I had the same idea using a surface plate.

 

[Bravo17]

nice