How can you tell if a bit is getting dull?

How do you folks tell if a bit is getting dull?

It no longer cuts well.

Some folks keep a detailed usage log.

Other folks will use a loupe to inspect tooling before each usage.

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I usually can tell by the cut itself in hardwood.

more dust than chips, and dust is hot: bit is dull. I found a wireless miroscope in my stuff, and use it to check the blades. And: I have a local bit sharpener (and -manufacturer), the best: Dinosaw in Hudson, NY.

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Well, “no longer cutting well” was a symptom, but I wasn’t sure if it was material or user error. I took @Emmess advice and bought a cheap digital microscope off of JeffBezosIsStarving.com

Observations:

My recently retired Cadence MFG 30* Jenny. I used this bit A LOT when I discovered inlays back in January of '24

My new girl, also a Cadence MFG 30* Jenny. Only about 50 minutes on this lady.

Stark contrast.

My old Carbide 3d #201. Has been my work horse for about 8 months.

My barely used #201

Microscope provided some great insight. I’m also going to make a spread sheet keeping track of usage. I love speadsheets!

Thanks y’all!

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