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That old timer who told me to back off my feed rate by 15% was dead right after I broke a $40 endmill in half
I was running a 3/4" aluminum block too fast and he literally grabbed my hand off the override knob and showed me the chips coming out blue instead of silver, and after I slowed it down the finish came out mirror smooth with zero chatter, has anyone else had an old machinist save them from wrecking a part?
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corablack1mo ago
Did you check your chipload after he showed you that? Blue chips mean you're cooking the edge, not cutting clean. That old school trick of watching chip color saves a lot of tooling, I swear by it now on every aluminum job I do.
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iris9271mo ago
Wait, isn't it actually blue chips that mean you're in the sweet spot for aluminum? I always thought straw or golden meant you're still fine, but blue shows you're actually getting the heat into the chip instead of the part. Could be wrong, but I've been running production jobs for years and my tool life goes up when I see that light blue coming off.
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tessa_murray1mo ago
Right, so now we're supposed to read chip colors like tea leaves. I'm out here just hoping the hole ends up in the right spot.
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