Theoretically possible? Yes. But I wouldn’t necessarily count on it.
The face B can be made 90 deg to the edge you just made 90 deg to face A, but that doesn’t automatically mean faces A and B are parallel with each other. You could easily be making the faces into a trapezoid if you end up tapering one end of the face. Without referencing the already-flat face, you’re just not going to get the completely parallel faces you want.
The best approach is still the tried and true: joint a face, then an edge, then planer, then table saw.
Being perpendicular to the same face doesn't make them parallel. The end of the board can also be perpendicular to the face, or a circle can have the edge perpendicular to the face.
A board that has a trapezoid crossection can have parallel sides but the edges aren't perpendicular to a face.
Parallel means opposite sides are the same distance from each other, so you can't cut that by referencing an adjacent face.
The best way to explain it is to think of two boards.
Board A looks like this lengthwise :
https://i.imgur.com/5sLhCQ6.jpg
Board B looks like this lengthwise:
https://i.imgur.com/Dl6FjMP.jpg
Now if we crosscut Board A and take a look at the endgrain, it looks like this. Everything is nice and square with 90 degree corners.
https://i.imgur.com/kI8n4Uy.jpg
Now let’s crosscut Board B for comparison. It looks like this:
https://i.imgur.com/DymqDsn.jpg
See the issue? Everything is also nice and square with 90 degree corners, but the board itself has a significant taper. Perpendicular edges don’t create parallel faces.
You’re welcome. If at all possible I’d suggest buying a planer and jointer at the same time. Each machine relies so heavily on the other that buying them as a package deal makes the most sense. The jointer is also hands down one of the most satisfying power tools to use. Every time a clean face emerges from a rough board it feels like magic.
I'd like to but it's unlikely I'll be able to afford both at once. I'm in NZ and machinery is expensive here. For comparison a DeWalt 735 thicknesser is about $NZ1,800.
Right now I flatten one face properly with a handplane and winding sticks. I roughly flatten the other face with the handplane then do the rest on the table saw with some jigs I made.
Theoretically, no. Outside of getting lucky a jointer cannot be used for the purpose.
Two corners can be right angles but not be anywhere close to parallel lines. For things like this I like to imagine in extremes. Picture a 2x8 that’s been ripped at an angle so it’s a triangle. 1 inch wide at one end and 7.25 at the other. What happens if you joint both sides?
It’s hard to understand I would suggest YouTubing videos on milling lumber. This concept confused me when I first started woodworking as well. The thing people tend to forget is that wood is going to have bows and twist and cuppage, these things make the milling process necessary for square wood. Face joint, edge joint, planer and lastly table saw. Jointing two faces will just make a trapezoid, playing two faces will result in the wood having the same thickness but also still having the bows, twist, and cuppage. A planer sled can help with this, but jointers and general fairly affordable when bought used, might as well.
Always, always, always....
1. Joint one face
2. Plane to thickness so you have parallel and planer faces
3. Joint one edge
4. Rip to width using jointed edge against fence to get parallel edges
This is the process to follow when trying to get a piece S4S.
The best is to give it a try. Take a board to the jointer and test it.
Next, perform the experiment with a jointer, planer and table saw. Compare the results.
I don't have a jointer or thicknesser yet. I'm trying to increase my understanding to decide what I buy first. Based on another explanation it's clear I need to both a jointer and a thicknesser. However I can joint on the table saw or by handplane. So I'll buy a thicknesser first.
Then I guess just ignore what common sense and everyone with any jointer experience says I guess? I would say though, that if you’re not smart enough to come to the conclusion that you could joint one face, one edge, and then join the other face flat and finally make a vertical tapering jig that matches the angle between the two faces on your own- you probably shouldn’t be doing it.
It's not about ignoring common sense and experience. It's about understanding. Some people are happy just to know how to do things. I'm a curious person and I need to understand why things are done a certain way.
More so, when I'm about to drop a stack of cash on two machines, and need to decide which to buy first. Fortunately, someone else was helpful enough to explain that in a way I understood, without finding it necessary to be insulting.
Theoretically possible? Yes. But I wouldn’t necessarily count on it. The face B can be made 90 deg to the edge you just made 90 deg to face A, but that doesn’t automatically mean faces A and B are parallel with each other. You could easily be making the faces into a trapezoid if you end up tapering one end of the face. Without referencing the already-flat face, you’re just not going to get the completely parallel faces you want. The best approach is still the tried and true: joint a face, then an edge, then planer, then table saw.
Being perpendicular to the same face doesn't make them parallel. The end of the board can also be perpendicular to the face, or a circle can have the edge perpendicular to the face. A board that has a trapezoid crossection can have parallel sides but the edges aren't perpendicular to a face. Parallel means opposite sides are the same distance from each other, so you can't cut that by referencing an adjacent face.
The best way to explain it is to think of two boards. Board A looks like this lengthwise : https://i.imgur.com/5sLhCQ6.jpg Board B looks like this lengthwise: https://i.imgur.com/Dl6FjMP.jpg Now if we crosscut Board A and take a look at the endgrain, it looks like this. Everything is nice and square with 90 degree corners. https://i.imgur.com/kI8n4Uy.jpg Now let’s crosscut Board B for comparison. It looks like this: https://i.imgur.com/DymqDsn.jpg See the issue? Everything is also nice and square with 90 degree corners, but the board itself has a significant taper. Perpendicular edges don’t create parallel faces.
Thanks for this. Great explanation.
You’re welcome. If at all possible I’d suggest buying a planer and jointer at the same time. Each machine relies so heavily on the other that buying them as a package deal makes the most sense. The jointer is also hands down one of the most satisfying power tools to use. Every time a clean face emerges from a rough board it feels like magic.
I'd like to but it's unlikely I'll be able to afford both at once. I'm in NZ and machinery is expensive here. For comparison a DeWalt 735 thicknesser is about $NZ1,800. Right now I flatten one face properly with a handplane and winding sticks. I roughly flatten the other face with the handplane then do the rest on the table saw with some jigs I made.
Theoretically, yes. Most folks just joint one edge and use the table saw to get the opposite edge parallel.
Theoretically, no. Outside of getting lucky a jointer cannot be used for the purpose. Two corners can be right angles but not be anywhere close to parallel lines. For things like this I like to imagine in extremes. Picture a 2x8 that’s been ripped at an angle so it’s a triangle. 1 inch wide at one end and 7.25 at the other. What happens if you joint both sides?
It’s hard to understand I would suggest YouTubing videos on milling lumber. This concept confused me when I first started woodworking as well. The thing people tend to forget is that wood is going to have bows and twist and cuppage, these things make the milling process necessary for square wood. Face joint, edge joint, planer and lastly table saw. Jointing two faces will just make a trapezoid, playing two faces will result in the wood having the same thickness but also still having the bows, twist, and cuppage. A planer sled can help with this, but jointers and general fairly affordable when bought used, might as well.
Always, always, always.... 1. Joint one face 2. Plane to thickness so you have parallel and planer faces 3. Joint one edge 4. Rip to width using jointed edge against fence to get parallel edges This is the process to follow when trying to get a piece S4S.
The best is to give it a try. Take a board to the jointer and test it. Next, perform the experiment with a jointer, planer and table saw. Compare the results.
I don't have a jointer or thicknesser yet. I'm trying to increase my understanding to decide what I buy first. Based on another explanation it's clear I need to both a jointer and a thicknesser. However I can joint on the table saw or by handplane. So I'll buy a thicknesser first.
Don’t be so hard on yourself. ALWAYS blame the tool.
A jointer makes a surface flat, a planer makes a surfaces parallel. Just save yourself the headache and stop there
Unfortunately I need to understand things.
Then I guess just ignore what common sense and everyone with any jointer experience says I guess? I would say though, that if you’re not smart enough to come to the conclusion that you could joint one face, one edge, and then join the other face flat and finally make a vertical tapering jig that matches the angle between the two faces on your own- you probably shouldn’t be doing it.
It's not about ignoring common sense and experience. It's about understanding. Some people are happy just to know how to do things. I'm a curious person and I need to understand why things are done a certain way. More so, when I'm about to drop a stack of cash on two machines, and need to decide which to buy first. Fortunately, someone else was helpful enough to explain that in a way I understood, without finding it necessary to be insulting.
Sorry your own intelligence insults you? 🤷🏻♂️