Got a square piece of wood for .99 cents that is a bit too large for a
Towel bar store wanted $27.00 for a simple wooden towel bar . What tool would be used to shave some wood? Yet retain its square configuration. Tools I have available
Miter Saw, Angle Grinder , Router, old fashion hard turned
Lathe, and a wood plane. Would I also need a caliper for the thickness?
See attachment

That appears to be a pressure treated 2x2 wood spindle. I would not use it inside for anything unless I knew what the pressure treatment was, older stuff used arsenic. I would plane it down to size but you did not list a plane so next best would be the angle grinder if you can use it as a sander

Hey Bob

He did list a wood plane.

The other problem with pressure treated wood is it has a habit of twisting/warping after a time.

Some big box stores, home depot for one, have plastic replacement towel bars that are spring loaded and cost about $6.00.

Chuck

Must have missed that, yes I would look for a better material maybe even PVC plumber or pipe