10) Double check your drawing.  Often the default on some design software is actually a very difficult feature to make.  Do you really need a bottom tapped hole?

9) Spend a few days with the QA department the first time they qualify your new part.  It will be eye opening.

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You have no idea what a 250μ milled finish is, until you see it and feel it.  These gauges are relatively cheap, durable, and a quick reference.  Having one around will make your drawings more accurate and ultimately save machining time on your parts.

Below is a handy reference chart from the Wikipeida article on surface finish.

Here are some gauges you can order from Amazon.  The less expensive one is cast and not calibrated.  This means that it’s not standards compliant, and not as accurate as the calibrated scales.  In my experience, this calibration is generally unnecessary with surface finish gauges.  Learn about surface finish calibration at the National Institute of Standards & Technology’s website.

What other scales and gauges do you keep around?

8. Machinists will often need to alter your part to machine some of the features.  Work through this together and you’ll both be happier.

7. When you first bring your drawing to the machine shop, it’s common to scribble notes and explain what’s “not that critical.”  This is a valuable exercise, but take the time to alter the drawing in your design software before giving it back to the machine shop.

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