Machinability Charts (and a challenge)

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Well-Known Member
HMEM Supporting Member
Sep 23, 2021
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South Central PA
While I mostly work in 6061, 12L14/15, 1018, 1144, 4130 and Acetal, every once in a while something comes up with a different recommended material. In order to make an informed decision between the alternatives I'll do a little research which includes looking at machinability. To assist with this, I use a couple of different charts:

My go to's are Carbide Depot's chart that has mostly steel & alloys. And this one, from Yankee Reamer, which includes other materials. Yankee also has excellent guides for selecting reamer and holes sizes. Of course, the two charts aren't based on the same scale, but the relative data is similar.

I hadn't paid much attention to some of the materials listed in the Yankee chart until earlier today when one item caught my eye, and then another one: it turns out the folks at Yankee have a sense of humor. See if you can spot the outliers in the Yankee Machinability Chart.
Hahaha, nice to see a bit of humor from people in industry once in a while. I'm sure I've got a bunch of the later one, the first would be nice to have but I would lose it in my shop!

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