Chris Schwarz's Blog

How Do I Sharpen a Rasp?

John Griffin-Wiesner writes: Thanks to your blog posting last week which alerted me to the closing of Auriou, I purchased my only three Auriou rasps. While explaining them to a non-woodworker friend on the phone he asked if rasps ever wear out or need sharpening.

Huh. I never thought of sharpening a rasp.

But rasps are metal, and all my other metal woodworking edges need replacing or sharpening at some point. I can’t fathom the sharpening of a rasp. But my friend couldn’t fathom the sharpening of a saw blade either — which I know is not too big a deal. Will these fine rasps wear out one day, or need sharpening, or … ?

Answer: There are (at least) two schools of thought on resharpening files and rasps.

1. Don’t be a snapperhead. Use it and throw it away.

2. Send it to Boggs Tool & File Sharpening Co. in California. Boggs uses a “liquid honing process” to remove material from the back of the teeth, exposing a sharp edge. I’ve used rasps sharpened by Boggs and I can attest that they work better than the tool did when new. These were not Auriou products, however; they were Nicholson patternmaker’s rasps. So I cannot say how the Aurious would do. It wouldn’t hurt to give Boggs a call and ask. Last time I checked, resharpening a cabinet-sized rasp was less than $10.

- Christopher Schwarz

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