Method for clocking a four jaw to a known reference point or datum. I use this technique for clocking rectangular or square stock in the four-jaw chuck. It is extremely accurate and it saves messing with toolmakers buttons, per drilling or any other means and less accurate ways such as clocking over the corners of the stock.
I mainly use it for getting square bar concentric, but yesterday it dawned on me I could take it one-step further and locate a known datum or reference point on the work piece.
It does not show it on the video but after machining the hole and counter-bore, I check the component for accuracy and it was within 0.001” in both directions.
I hope you find it a useful video and thank you for taking the time to view
The Home Engineer