The Boring Bar

1. Incorrect feeds and speeds

Running tools too fast or too slow.
Most tools are run at the improper feeds and speeds. Machinists rely on the managers or sales representatives to give information on the correct cutting parameters. Always make sure you have the manufacturer’s catalogue handy to get the right information.

2. Running coolant on indexable milling tools machining steel and stainless

Modern carbide inserts run at cutting speeds of over 200m/min.
Running coolant at these speeds, you can never guarantee you will have coolant on the cutting-edge 100% of the time. The nature of heating and cooling the carbide leads to thermal cracking and poor tool life. Turning off the coolant and running dry can double the life in some cases.

3. Measure twice, cut once

You know there is only one thing that can save you is to double check. We all get complacent, but spending 5 hours on a workpiece only to machine the last part incorrectly is devastating.
You don’t want to be caught out by reading 0.05 as 0.5

Problem solving and learning from your mistakes is part of the process.