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Changing of the Knives


How did you spend your weekend?

Well, I put in a couple of hours getting ready for a new project here in the American Woodworker shop. I hadn't changed the knives in our jointer for over a year–can you believe it? Our jointer's cutterhead has segmented and indexed carbide knives, and they just go and go and go.

But everything gets dull eventually, and these were due. Each knife has four sides, and "changing knives" is simply a matter of loosening each one, cleaning off the pitch that accumulates on the knife's cutting edges, rotating the knife one turn, and fastening it back down to the cutterhead. An indexing mark on the knife lets you keep track of which edges are dull and which are new.

Sounds simple, right? Well, it is. But with four rows of ten knives each, and all the cleaning in between, this took me the better part of two hours. I could have removed and re-set a standard set of jointer knives in half the time, but there's no fussing with knife height or outfeed table height with these indexed puppies. I'm not sure if that's a big advantage or not-I like being a precise machinist now and then.

I still prefer  carbide knives, though, even if they take longer to change. First, you don't have to do it so often. And second, you can joint any material that you can cut on the tablesaw, such as MDF or fiberboard. Quite the deal!

If you have any opinions or questions about carbide cutterheads, please leave a comment below.

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Wayne Hiatt wrote re: Changing of the Knives
on 03-16-2009 1:30 AM

Is there a way I can get those kind of knives for a thickness planer (Ryobi 12")?

Tom Caspar wrote re: Changing of the Knives
on 03-23-2009 11:39 AM

Hi Wayne,

Byrd Tools,, makes replacement cutterheads for many jointers and planers, but probably not for your machine. Planers with universal motors don't have enough power to drive a carbide cutterhead, I believe.