Sharpening Jointer Blades?
Q. A reader sharpened his hard-to-find jointer blades, but they are now off by 1/32" from one end to the other. He can't seem to get them adjusted to work right. Any advice?
Simon Watts: "I assume that you are setting the knives in the cutterhead with the small metal jig supplied for that purpose? If the knives don't line up withthe outfeed table then either the cutterhead is out of whack, the table is twisted--or both. I suggest you first lay an engineer's straightedge on both the outfeed and infeed tables and check the alignment with feeler gauges. The two surfaces should be in exactly the same plane. If not, shim the ways on the infeed table until they are.
Next use a dial indicator to check that the cutterhead assembly is exactly parallel to the outfeed table. If it's not, slack the two hold-down bolts and shim up whichever side is lower. If you don't have shim stock available, aluminum foil works almost as well."
Ian Kirby: "You don't sharpen jointer blades yourself; you send them to a machinist who will grind them. The machinist will grind them so they are parallel, back edge to sharp edge, and so they are equal in width. This means they are the same size and weight as one another. When the knives are returned to the cutterhead, it will be in static and dynamic balance: something like the wheels on your car.
Advice: find a machinist who sharpens jointer knives."
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