I have a little Porter Cable (PC160JT) bench-top jointer for economies of space and cost. I was having some issues getting good square sides, so I spent some time tuning it up. I wanted to document this for myself as a reference but also hope this helps someone who is on a similar journey.
I have three tasks in tuning the jointer. Getting the tables aligned hopefully is something that only needs to be done once or at least once in a great while. Since the blades are a consumable, the process to align blades will be done periodically. The third is the fence, and I do check this each time since it’s a simple, but essential task.
First, some background on jointers because through this I learned a few things. The primary function of a jointer simple flattens the surface of a board. The secondary purpose is to make an adjacent edge 90-degrees square. That’s it. After you have that 90-degree edge, you take the board to a planer with the jointed face down and make the opposite face parallel. Then, you go to a table saw with the jointed edge up against the fence and do a rip cut to make the opposite edge parallel. After this, you should have a board that’s square all around. Depending on the board, it could look a little weird coming off of the jointer. It may have a wedge shape or otherwise appear to have gone wrong, but if the jointed edge sits flat and is square with the jointed face, the jointer has done its job as directed by the operator. It’s now up to other tools to match the jointed face/edge.
To achieve this, a jointer has four basic components. There’s an in-feed table, out-feed table, blades, and a fence. To tune the jointer, all four must be aligned. The way the jointer works is you want the out-feed table is slightly higher than the infeed table and the cutter blades are set to the same height as the outfeed table. When you push a board along the in-feed table, the blade cuts into the wood and establishes a new surface that matches the out-feed table. By taking multiple passes, you can cut down any high spots on the board and level it off. You can adjust the in-feed table by raising or lowering it take a deeper or lighter cut. Lastly, there’s the back fence. To make a square edge, the fence must be adjusted to be 90-degrees from the table and the jointed edge of a piece of wood is pushed against it.
There are a number of tricks and jigs for adjusting jointers. I tried a bunch, but what worked best for me is using a dial indicator with a support base. Dial indicators are relatively inexpensive and can be valuable with other machine calibration and measuring.
The second item is some shim washers. I bought a set from Amazon that had three sets of shims in varying thickness. You can also make your own by cutting up a soda can and drilling holes in strips, but I found the shims the easiest. For me, when I made one adjustment, it affected the other three corners of the table. Controlling the thickness of my adjustments was helpful.
When working around the blades, ensure the machine is unplugged. To have full access to the table, I remove the blade guard and fence.
On a jointer, it’s important that the in-feed and out-feed tables are coplanar. This means while one table is slightly lower and adjustable, it is still parallel to the other table. If they’re not parallel, any misalignment between the tables will be transferred to the wood since that is the reference surface for the cutter. On the Porter Cable jointer, the tables are held down by bolts and that’s the only opportunity for adjustment. By placing shims between the bolts and frame, you can alter how the table sits on the frame relative to other bolt locations.
Ideally, I’d probably measure the out-feed table against the in-feed table from various points on each table, but the arm on the base wasn’t long enough to span the entire jointer. So, I did it in parts starting with the out-feed table. I placed the base on the out-feed table over each bolt and measured the table near the other three bolts. I then removed the table and placed shims under the bolts where I think they needed to be. Then I bolted back down the table, measuring again, rinse, and repeat. This can be a chore.
Once I had the out-feed table level across itself, I raised the in-feed table all the way up. I took my measurement by placing the base on the out-feed table and then measured the end of the in-feed table. Then I took additional measurements of the in-feed table like I did on the out-feed table. Then, I removed the in-feed table. I adjusted the table using the shim washers between the bolts and the frame. I put the table back on, then measured again. Rinse and repeat until I got it as best I could get. This can take some time and patience. The good thing is the Porter Cable jointer is small, so I brought it into the house and did this while watching a ball game.
After I called it good enough, my tables are 1/1000 – 3/1000th of an inch off across the span. We’ll see if this holds up. If these were cast iron, I’d guess they would be pretty stable, but not sure what to expect with aluminum tables. I’ll avoid lifting the jointer by the tables and generally not use it as a resting spot for heavy things. I’ll probably recheck them whenever I replace the blades.
The table hopefully is something that only needs to be done once, but the blades are something that will be a regular maintenance item. The dial indicator works great for this. The Porter Cable jointer has two blades in the head. Each blade is held by a bracket and that’s secured by four bolts. Each blade also has two adjustment screws. The adjustment screws raise and lower the blade inside the mount. To replace blades, you take off the bolts and remove the blade from the bracket. To adjust the blades, you loosen the bolts, make the adjustments with the screws and then tighten it back down. One other item of note is there’s a blade lock painted red.
So, the objective here is to get both blades coplanar with the tables and set at the same height as the outfeed table. If the blades are not coplanar you’ll have uneven cuts. If the blade is above the outfeed table, it will snipe off the end of a board. Snipe essentially is taking a deeper cut on the last inch or so of a board. If the blades are set below the outfeed table, it won’t cut evenly or at all. So, this is a precision adjustment that’s perfect for a dial indicator.
First obviously ensure the machine is unplugged. You’ll also need to take great care while working with the blades because blades are sharp.
My process for aligning blades is, first if not already done, I remove the blade guard and fence. You’ll need hex wrenches to remove the guard, loosen the bracket bolts, and adjust the screws. Then, I move the cutter head to expose the first blade. I then loosen the blade holder bolts. I move the head further to lock the head in place with the safety lock. Since there’s some play in the lock, I push the head clockwise just to have a consistent measurement of both blades.
Now it’s time to measure. I measure the blade at the set screws, so I first take a measurement on the out-feed table in-line with the set screw. I turn my dial readout to set it to zero. Then, I move the dial on to the blade. I push the probe over the blade until I find the highest point. Once the indicator starts to fall over the edge of the blade, I back off. I then turn the adjustment screw until it reads zero. I repeat the process for the other side of the blade with the other set screw. Then I unlock the safety, turn it, then tighten the blade holder bolts. Then I turn the head back, lock the safety down, then verify my settings. If needed, repeat for any further adjustments. I then repeat the procedure for the other blade.
I always take the measurement of the out-feed table at the spot of the blade measurement to ensure the blade is both coplanar to the table and level with that spot on the table. If I’m finding the blade is moving around on me between adjustments, I’ll split the process per blade into two parts by loosening only two the top two/bottom two blade holder bolts and only one set screw at a time.
Then I unlock the blade safety and replace the blade guard.
To verify everything, I lay a piece of wood across the blade and manually turn the head. It should push the wood back a short distance. You can measure this distance if you wish, but this is just piece of mind thing that the blade isn’t too low.
There’s a lot of words there, but it’s a pretty simple process. I can replace and adjust both blades in about 10-15 minutes.
This one is pretty simple. I take a 6-inch combo square and set it on the table and against the fence. I adjust the angle of the fence until it’s 90-degrees. With this set, my jointed surface will be 90-degree when pushing against the fence.
Once all the adjustments are made, I plug it in and try jointing a scrap board. I should get no sniping and end up with a face and edge that is 90-degrees square down the length of the board.
This little jointer is running well enough for the price and the size is convenient. One issue I run into is over time as the blades wear, it doesn’t cut well. The jointer cuts at a taper with the trailing end missing the knives. This seems the symptom of the outfeed table higher than the knives, which makes sense if the blades lose their edge. To compensate, I’ve been raising the knives about 1/1000 above the table rather than dead even, which seems to fine without any snipe. It seems I occasionally need to adjust the knives, which can be a bit of a pain. This wouldn’t be a problem if the jointer’s outfeed table could be adjusted.
One other thing, which I’m still working on, is getting the jointer tuned is only part of the equation. Technique plays a big part in results and I’m still learning. It’s much easier learning though knowing the machine is tuned up and running well.