Edge Jointing

[Jerry Thompson]

Using a hand plane to edge joint two boards I plan to do them at the same time. That is run the plane over both edges at the same time.
Now how do I match them up? Do I lift the outer edges up and mate them that way? I have tried this with poor results. I seem to get a joint that will not lay flat and if flat it is open on one aspect.

[Clint Jones]

Is the plane blade projecting square with the mouth?

[Johnny Kleso]

When jointing you hold the front of the sole between your fingers on the front..

Plus check the edge with a square before you finish..

Another advanced thing is that old timers do is called "Spring the Joints"

That means they make a very shallow belly in the center of the boards as ends over time will shrink more then the centers of boards so as the ends shrink the extra compression from clamping equals out over a long time...

I not sure if I explained it so you understand :(

[Bob Coleman]

More critically, is the plane iron edge ground flat and are you taking a continuous shaving the full length of the edge? You should be able to rotate the boards around the jointed, touching corner (so now the sides that were clamped together are both facing down) when you are done, so no matter how square the edge is, the two opposing edges will mate.

I use Stanley's attachable fence as well to get as square as possible.

[Jerry Thompson]

All is square, sharp etc. I just do not understand how the jointed edges mate. Looking down on the edges just jointed do I raise the bottom of the boards up right and left letting the jointed edges fold into themselves? Errors are supposed to cancle each other but right now I am confused. The little stuff gets me. I have a very poor mind when I comes to mechanical things. I mean very poor. I still have trouble putting a plane back together and I have done it countless times. Just as a perspective.

[Mark Stutz]

Jerry,
You have it correct. As a way to be sure of yourself, draw a reference triangle on the face sideor the two laying in their final orientation. put the marked sides out with the two edges to be jointed up. When you fold them back flat the triangle will align and you know you have them in the original orientation.
I have found that getting both boards with as square an edge as possible is beneficial and for me made glueup easier. I also spring the joint as Johnny described.

Mark

[Jerry Thompson]

That puts it in perspective. I shall give it a go come Sat.
Thanks.

[Mike Brady]

I just used the "book-match " method described above on a table top. The result was the best jointed edges ever for me. I was sceptical, but the errors in squareness did cancel out. I used a #7 plane and did try to take a couple more strokes inboard to create the sprung effect that JK mentioned. That worked too.

[Larry Williams]

...Errors are supposed to cancle each other but right now I am confused. ...

Match planing was only traditionally used with very thin stock. I don't believe you'll find any evidence this was a traditional trade practice on thicker material.

The error in squareness across the width is supposed to be the same on both pieces. The problem with match planing is that error along the length of the edges is doubled. I think it's far more difficult to get s perfectly straight edge than one square to the face. The difference between the two is really staggering. For example, let's say you're having a real bad day and end up with 10% error. If your board is 3/4" thick that's .075" across the edge. Let's also assume you're working a relatively short piece of stock that's only 24" long. 10% of that is just under 2 1/2" and, with match planing, that's doubled to just over 4 3/4". I realize this is an extreme amount of error but it shows how much more accuracy is required to get a straight edge.

I think you'll find it's easier to adjust the pieces of stock to each other rather than assume you'll end up with a perfectly straight cut when match planing.

[Mark Stutz]

Thanks for the history lesson, Larry. That probably explains why the process has worked well for me at times and other times seemed like a complete disaster...set it aside and come back another time. Depends on how much error I introduce at any particular time.

Mark

[Jerry Thompson]

Larry;
I gave it another go. I used two boards and did them at the same time. I had fair results. I then put a straight edge to one piece and maked out what need to come off. I used my #5 and went after it.
I did the same with the second board. They both fit very well. I then put them both together and made two passes with the plane and they matched up as if a pro had done them.
I still do not know what I am doing wrong starting out with two ay the same time. I am the sort that needs someone standing @ my side to show me what I am doing wrong.
Thanks to everyone for helping.
Jerry

[Michael Fross]

I've always looked at it this way. If you place the 2 boards together when you plane and your plane is tilted say 3deg to your left by mistake, you'll have created a small slope across the 2 boards.

If you then put the boards on the bench and move the bottoms away, the boards will fold together in the middle. The error should cancel each other out as the high point (right side of right board) will mate with the low side (left side of the left board). This is hard to write, but I can picture it very clearly in my head.

At least that seems to make sense to me right now..... :)

Lastly, I thought spring was put in to ensure that the end of the board would not be in tension thus helping to keep the joint from coming across there.

Michael

[Circa Bellum]

I've always looked at it this way. If you place the 2 boards together when you plane and your plane is tilted say 3deg to your left by mistake, you'll have created a small slope across the 2 boards.

If you then put the boards on the bench and move the bottoms away, the boards will fold together in the middle. The error should cancel each other out as the high point (right side of right board) will mate with the low side (left side of the left board). This is hard to write, but I can picture it very clearly in my head.

At least that seems to make sense to me right now..... :)

Lastly, I thought spring was put in to ensure that the end of the board would not be in tension thus helping to keep the joint from coming across there.

Michael

But in reality my experience has been more like Jerry's. I'd love to have someone that I can get with to SHOW me how to set up my planes and use them. Anyone in central Arkansas willing? (hint hint)