Knives out

The key to good woodworking is to keep all cutters and knives sharp. Also key? Don’t wreck them beyond repair. 

I held a whole-shop machine tuneup day recently. No work, just a full day of adjusting, cleaning, sharpening, and the like. As part of that I replaced the three knives in my planer, something I hadn’t done in longer than I care to admit. But the change-out was easy and straightforward, and planed surfaces were back to being smooth as silk. 

But since then, I did something that absolutely ruined them. And here’s the thing: I have no idea what it was. Everything was fine the last I remember. Admittedly, I hadn’t used the planer in a couple weeks, but when I fed some stock just a couple days ago, I got some horrible ridging on the otherwise smooth surface. Take a look below. 

That’s just a piece of 1x4 poplar I ran through the center to take a photo, but the ridging is like this across the entire 13" of the planer’s width. The issue, of course, is that the knives were chipped. But how? I don’t recall any issues last time, but something I planed between then and now clearly did a lot of damage. 

Anything a planer knife hits that’s not plain wood can do that — nails, embedded sand or other debris, even hardened glue. I’m sure everyone reading this has experienced it from time to time, but when it happens, it usually manifests itself in just a spot or two. That can be easy enough to live with. But to have ridging like this across the entire planing width, and for it to have happened in such a short amount of time?  I’m clueless. 

Since the stock I needed was otherwise planed correctly and all the ridges were raised, I can deal with it with diligent sanding for now. Needless to say, I’ve ordered a new set of knives and will be enjoying another tune-up day for that planer as soon as they get here.