What Is a Test Bar and How Is It Used for Machine Verification
A test bar is a precision-ground bar that fits into the machine spindle. It extends from the spindle nose and is used to check the machine’s alignment. It’s a simple tool, but it’s essential for verifying machine condition. I use a test bar for every machine installation and after any significant repair. The standard that governs this procedure is VDI 3212, which defines the acceptance test requirements for deep hole drilling machines with one or more spindles. I follow VDI 3212 as the baseline and adapt the tolerances based on the specific job requirements. ...