Planer knives will sitting dull them?

[Paul Steiner]

At my school we are resurrecting a powermatic 160 the knives in the machine are dull. But we found 2 sets of knives for a 160 sitting on a shelf in storage. They are partially wrapped in the paper our sharpening service uses but they were exposed to the air. The knives have been sitting for at least 15 years and look/feel sharp no rust or defects. Will sitting out dull the knives? Should I send them for sharpening? FYI sharpening is provided free by the county.

[Gary Max]

Heck sounds like they are good to go. Rust would of been the Biggggeeee

[David Hawxhurst]

as long as the blades are not resting on the cutting (sharp) side the edges should dull. they should be fine.

[Chip Lindley]

Save the taxpayers a few bucks. Use the found knives! Send only the dull set out for sharpening.

[Prashun Patel]

You can also check the edge with a jeweler's loupe if you don't just want to install and test.

[Jim Rimmer]

You can also check the edge with a jeweler's loupe if you don't just want to install and test.
I found a set of loupes at Harbor Freight for about $6 or $7. Use them a lot.

[Ron Bontz]

Oh sure. Make me go to Wikipedia to find out what a loupe was.:)

[Chip Lindley]

A jeweler's loupe is a bit of overkill. Machine knives can be checked by eye for a sharp edge the same way pocket knives have been for eons! Hold the knife perpendicular to your line of sight and rotate the edge up and down with a twist of the fingers under strong overhead lighting. (kind of like reading an old glass/mercury fever thermometer) Any nicks will glint as a shiny spot on the edge. A totally dull knive will reflect shiny light all along the edge. If the knife passes eye inspection, slice a sheet of paper with it, held in mid air between two fingers. It should slice easily through with NO sawing. That's scary sharp!