Edge planing a board straight

[Mike Henderson]

How do you edge plane a board straight (with a hand plane)? I've never figured out how to do it except to take a known straight edge, such as some MDF cut on my table saw and lay it on the edge to check if it's straight. Then, I can focus on the high points and get the board straight to my satisfaction. I'm talking about a long board and not something 2' long. Maybe a 6' board.

So maybe I should ask the question in a different way, "How do you know an edge is straight when hand planing it?" I've tried looking down the board, and maybe my eye is not good enough, but it can look straight and still be bowed when checked against a known straight edge. Any alternative to checking it with a known straight edge?

Mike

[Sean Hughto]

Are you using a jointer - like a 7 or an 8?

I would think keeping an edge square to the faces would be a bigger challenge for most hobbiests than straight?

But to your main question, if the board needs to be straight to edge joint for example, I think testing the edges or using the bench top or what have you to check your result for "straight" is SOP.

[Preston Baxter]

Here is a method that I've adopted that almost always insures a flat edge without having to check with a straightedge. It works for me, but a lot may depend each individuals planing technique.

If the plane is long enough for the job, then handplaning will almost always result in a flat or rounded surface. Once I get to the point where I am taking a complete shaving from end to end; I pull back the iron for a very thin shaving, then try to plane the edge hollow. In other words, I start 1-2" in past the edge and plane to 1-2" in from the other end. When the plane stops cutting, the board is now very slightly hollow. I now take one or two full length shavings to bring the edge to flat, or near flat. You can judge by the shaving to how flat the board is getting.

At the moment the plane is taking a full length shaving again, the board is flat, any more planing from end to end risks rounding again. I prefer edge jointed board to have just the slightest hollow. This reduces the possibility of the ends of the glued up panels from splitting later.

[David Gendron]

+1 on Preston's description, that's the way I do it and it work realy well. One other way I use some time, if I know that one edge is "flat" is to scribe a line from it and plane to the line. If your scibed line is deep anought, you will notice when you get close to your goal, by having a small "feather" of wood at the edges of the board that will indicat to go easy and mabe to take a finer shaving! hoppe it make sense!

[Mike Henderson]

Sean addressed this, but my real question is, "How do you know if the edge is straight?" By this, I mean straight from end to end. For the purposes of this question, I'm not concerned with whether the edge is square to the faces of the board - only if it's straight from end to end.

Is there any way to know if the board is straight except to test against a known straight edge (or as Sean suggested, the top of your bench).

Mike

[Of course, if you check against the top of your bench, how do you know if the top of your bench is straight?]

[Tom Winship]

Preston, in para. 2, when you say you start in from the end and stop short of the other end, I'm assuming you are saying to start and stop the plane iron at these positions.
I also seem to have a problem with squareness of the edge. Any suggestions on that?

[Michael Faurot]

I also seem to have a problem with squareness of the edge. Any suggestions on that?

A No. 95, used in combination with your jointer, does the trick to help insure the edge is square.

95.jpg

The one pictured is from Lie-Nielsen. But vintage Stanley or new Veritas would work also.

[Preston Baxter]

Sean addressed this, but my real question is, "How do you know if the edge is straight?" By this, I mean straight from end to end.

With the method I use, the length and inherent straightness of the jointer plane determines the board straightness. If the edge is planed hollow with stop shavings, then a final, full length cuts are made until a full length shaving appears, then the edge will be straight due to the flatness of the plane. That is of course assuming the sole of the plane is not badly concaved.

I think I picked this up from watching the Jim Kingshot and David Charlesworth bench plane videos.

Preston, in para. 2, when you say you start in from the end and stop short of the other end, I'm assuming you are saying to start and stop the plane iron at these positions.

Yes, I am referring to the plane Iron at these positions.

I also seem to have a problem with squareness of the edge. Any suggestions on that?

I keep a small metal square handy that I can quickly pick up and check at least three points along the board, for edge to face squareness. Having a slightly cambered iron on the Jointer plane really helps in squaring edges and keeping them square. With the camber, if you keep the board's edge centered under the plane, it will cut equally. It you let it ride off to one side, it will cut more on that side. So you check it with a square, mark or make a mental note of the high points, and steer the plane accordingly to take out the error. The Charlesworth planing video goes into good detail about this technique.

[Jim Paulson]

Mike,

To compliment what has already been said, I usually rely on my 4 foot aluminum level to check for high and low spots. It is handy and I've had go experiences using it. Whenever I'm edge planing much over 2 feet in length I'm reaching for my number 8 Bailey once the highs and lows are smoothed.

If the length is sufficiently long one can also check straightness with a chalk line held from end to end and snapped on the side of the board.

But now with that said, I have less interest in using a reference as well. So I am building a couple shooting boards so that my board edges will come out at right angles and straight. My low end power joiner usually causes me to touch up the edges anyway so I'm moving in the direction of relying more on hand planes. I want to plane edges on drawer fronts and case sides and I'm making a four foot long shooting board. Charles Hayward in Cabinet Making for Beginners even talks about using a five foot long shooting board.

I think a lot of people think of shooting boards for trimming ends, but they seem to offer additional benefits with edge planing. Food for thought.

Jim

[Pedro Reyes]

Sean addressed this, but my real question is, "How do you know if the edge is straight?" By this, I mean straight from end to end. For the purposes of this question, I'm not concerned with whether the edge is square to the faces of the board - only if it's straight from end to end.

Is there any way to know if the board is straight except to test against a known straight edge (or as Sean suggested, the top of your bench).

Mike

[Of course, if you check against the top of your bench, how do you know if the top of your bench is straight?]

Sorry to be like this and answer with a question, but is straight better than having a slightly convex edge? I do what others have mentioned and plane a slight hollow, so I don't worry about measuring for a straight edge.

Is the straightness critical, perhaps I am missing something.

/p

[Hank Knight]

Mike,

This probably isn't a direct answer to your question, but I'm most concerned about "straight" edges when I'm jointing two boards for an edge glue-up. In this case, I use the two boards as references for each other. I joint one until it is "straight" and square as best I can tell (I do check with a straight edge and a square). Then I joint the other board so that it matches the first one. I really don't care if it's "Starrett straight", I care only that it matches the first board's edge. If I can balance one board on top of the other, edge to edge, with no rocking or slipping and there is no light between the two, I'm there. If the mate between the two is right, the balance feels solid. If the balance is the least bit precarious, if the top board wants to spin on a high spot or wobbles the least bit, I take another shaving or two. More often than not I can tell exactly where the problem is and direct my attention there with a bare shaving or two. Then I go back and take one full length, end-to-end shaving and try the balance again. I repeat this until I get the desired match.

I don't "spring" edge joints, but it's easy to do after you've reached this point. Just take a thin, less than full length shaving from one of the boards to let a little light through and then pull the joint together with clamps. If you have a good solid match to start with, a very thin, full width shaving from one of the boards shouldn't affect the match except to give you the "spring."

For most other situations, "eyeball straight" is fine.

Hank

[Randy Klein]

+1 on everyone who has mentioned stopped shavings, followed by through shavings until a full shaving appears. Assuming your plane is flat enough, this works every time.

Anyways, there is no way to have a perfectly straight edge and no real need for one, IMO. I simply shoot for the smallest convex edge that would become concave with one more through shaving.

[Bob Glenn]

Mike, it seems to me that if you took two boards and planned them together side by side until you were getting continuous shavings simutaneously off of both, you would be able to tell if they were flat by comparing the two edges against each other.

If you were low in the middle, there will be a gap when the boards are edge on edge. If the boards rock back and forth from end to end, you know they are high in the middle. If the boards tilt back and forth from corner to corner, you know they have a twist the length of the edge.

If they sit flat, I think then, they must be straight.

[Mike Henderson]

With the method I use, the length and inherent straightness of the jointer plane determines the board straightness. If the edge is planed hollow with stop shavings, then a final, full length cuts are made until a full length shaving appears, then the edge will be straight due to the flatness of the plane. That is of course assuming the sole of the plane is not badly concaved.

I keep coming back to my original question -"How do you know the edge is straight?" You can believe the edge is straight off the jointer plane, but how do you verify that?

The only suggestions I've read here are to use some reference straight edge.

When we do the face of a board, we use winding sticks to verify that there's no twist in the board. I was wondering if there's anything other than a reference straight edge to check an edge for straightness.

Mike

[Mike Henderson]

Mike, it seems to me that if you took two boards and planned them together side by side until you were getting continuous shavings simutaneously off of both, you would be able to tell if they were flat by comparing the two edges against each other.

If you were low in the middle, there will be a gap when the boards are edge on edge. If the boards rock back and forth from end to end, you know they are high in the middle. If the boards tilt back and forth from corner to corner, you know they have a twist the length of the edge.

If they sit flat, I think then, they must be straight.

I thought about that but I've had situations where I wanted a straight board and didn't need a second one. I guess I could use a sacrifice board just to check for straightness but I was wondering if there's any other way.

Mike