New woodworkers are often confused by the difference between jointers and planers. I know this because I get asked what should I get first, a jointer or a planer, and my answer has not changed on that topic, in my opinion the jointer is probably the best choice for most people, and if you have planer, you will still need a jointer. I often wonder if one of the reasons for that is because we frequently call "thickness planers" the shortened term of "planer" and "jointer" terms is shortened from "surface jointer".
I have seen people trying to "plane" wood on a jointer and what happens most of the time is you end up with wood that is wedge shaped. Similarly, jointing on the planer, is possible in some instances but you need to know how to do it in order to get usable wood.
The best and safest woods to joint using a planer are thicker boards, that will need to be long enough to satisfy the safety aspects of your planer. Most planers need wood to be at least 14" - 16" long, otherwise you risk the wood getting turned around inside the planer and either damaging the machinery and or the user. Something well worth avoiding.
The first step in making a planing jig is to find the flatest and widest board that will pass through your planer uninhibited. My planer is a 15" so the widest I could comfortably use was 14" and I selected High Density Fibre Board as it a very hard material that is very flat (but always be sure to check it before you purchase it).
Plywood is seldom a good choice for this kind of a jig. There is too much natural wood in plywood and depending on your environment, plywood can often warp and move as it attracts and expels moisture. Natural woods glued together are also not a good choice for the same reasons outlined above.
There is little to do to prepare your board. The length does not matter, but I recommend that you not make it too long because the whole jig needs to be manageable. My jig is about 5 feet long which I plenty because I seldom expect to be trying to joint wood that is longer than about 4 feet long and this gives me a bit of leeway. The biggest chore is to glue a small piece of wood across the back of your board to act as a stopper. Do NOT use screws or nails to attach this backer board. You will not want your planer knives to ever come in contact with nails or screws and glue should work just fine.
In the set-up of placing a board on your jig, the back of the board wants to be touch the backer board you have glued on. I prefer to use anti skid material for this when ever possible. The final step set the wood you want to joint on your jig. I like to position it so that the high side of the wood will be towards the back of the jig. You will need to set in place small wooden wedges in all the places where there is a gap between the jig and the wood you are jointing. Sometimes you will only need one, other times you may need several. These wedges need to be snug but not so tight that they move the wood you are jointing. It is also possible that the wedges will need to be taped to the jig board so they do not move. You may even need to use some small brace blocks on the side of the wood you want to joint it it looks like it will move around on you.
Once you believe your wood is positioned properly and supported properly on your jig, you will need to set your planer up so that it will only take off the high points. DO THIS WHILE THE PLANER IS UNPLUGGED AND TURNED OFF - for safety reasons.
When you are satisfied everything is set, turn your planer on and start the wood by easing it into the planer as you normally any wood that you are planing. THEN MOVE TO THE FRONT OF THE PLANER - to receive the wood as it comes through. NEVER try to push wood through a planer, or stand at the back of the planer, always move to the front and if the wood needs a bit of a hand coming through the planer, you can pull it from there.
After one pass through the jointer you can start to determine a proper height and continue jointing until the top side of your board is jointed from one end to the to the other.
When your board is fully jointed on one side, it can be flipped over and planed like any other board to give it an even thickness from one end to the other ... and presto, you have a jointed and planed board ....
Copyright Colin Knecht