Do you remember when the weather in Pennsylvania was nearly perfect with it's 60 degrees, sun, and a nice breeze? No? That's probably because it only lasted for four hours one day last week and it likely not to be seen again until April. But, on such a lovely day, the windows and doors to the shop were thrown open and we were happy to welcome a moment of springtime. During this breezy afternoon, I learned to chance the knives in a jointer!
After removing the power, all the guards, and fence, you can actually get to the knives safely which seemed to me to be a good first step. From there, a little wrench will do the trick to loosen the bolts that hold the knives tight into place. Depending on the jointer, the knife may have springs behind it, in which case it will raise up as the pressure is released. Now, we take out the old, presumably dull blade out and put the new, sharp one in it's place. My simple-minded logic said, "alright, tighten up those bolts again and let's move it along." If only it were so simple.
Again, depending on the jointer and the lack or presence of springs will determine whether I reach for the Jointer Pal. The jointers with springs pushing those blades up need the aid of something to hold them down and even with the jointer table. To do that, the Jointer Pal and it's strong magnets stick to the jointer table and thus it pushes the blade down onto the springs to the 'correct' height. I use the term 'correct' loosely because, again, if only it were so simple.
It's time to whip out the dial indicator. Now, I don't mean to brag, but we are pretty serious about woodworking over here so we have the most sophisticated of jointer blade changing tools. You can see me using the dial indicator in the photo, but what it does it tell you exactly how high or low the blade it with respect to the height of the table. The key to this process is making sure that the blade is at an equal height across the whole thing. The dial indicator needs to read zero all along the entire blade.The Jointer Pal did a sufficient job of lowering the blade onto the springs so I didn't have to slice up my hands doing it but it won't make the blade height as concise as we need it to be. Therefore, I would spend the next hour reading the dial indicator and raising/lowering the blade ever-so-slightly at either end until it was perfect.
This is where things get tedious so, I will spare you the details as I spent a good portion of an hour tweaking the blades to be the correct and even height. But, finally I managed to get a blade even all the way across and just as I was about to pat myself on the back, Rob was kind enough to remind me that there were three knives in each jointer. And thus, the process began again. And again.
The moral of this story is that changing knives in a jointer may not be the most fun task in the world but, if I can do it, you can do it. Put on some calming tunes, settle in for a while (because it will take a while), and know that when you joint that first board with your new, sharp blades, it'll all be worth it.