>I am making an small table top. It is approximately 42" long 20" wide. It is of Cherry and all goes well so far. Mostly done by machine. Jointer to remove cup and twist on one face on boards 6" or less wide. Then down to a hair above desired thickness on planner per board. Next glue up two boards so I can run that through the planer to clean it up. There's the hangup for me.
I am sure there will be a less than a true flat surface after glue up. just running it through the planer won't fix that.
I am thinking I can use my 4 1/2 smoother with some method to true up one face prior to running it through the planer. I've read about winding sticks but not sure if that is how I should go about it.
Advice appreciated.
And of course, after the two 12" planks are trued, I will glue them together (after edge jointed). Back to whatever this process is by hand.
>"Planecraft" and "The Hand Plane Book" are both good - the former is cheaper, from Woodcraft (more expensive used on Half.com - go figger). These will offer hours of useful reading.
Winding sticks are nothing more than two straight, parallel-sided sticks. You can make them from wood, or you can cheat (it turns out a high percentage of this community does) and buy aluminum angle stock from your local big box store - 48" of 1-1/2" by 1-1/2" should be fine, cut in half to make two. People often spray one black, to increase contrast. I scored two cheap aluminum levels at garage sales ($1 each), knocked out the vials so I wouldn't confuse them with a real level, and use those. One happened to come already painted black. Lee Valley sells some right pretty aluminum winding sticks that I plan to buy right after I win the lottery (they're actually pretty reasonable at $24.50, but, since that's ten times what I paid for mine...but if you're buying aluminum angle retail, you might find them competitive - I don't know what angle's going for these days).
Flattening goes from coarse to fine, with coarse using a plane iron with a lot of camber. It can be done with one plane and one iron in it (I have), but it takes a lot longer.
The idea is to find out whether your piece is "in wind," meaning twisted, with the winding sticks. Put them across the board toward opposite ends. Squat down past the end of the board, and look. If the board is in wind, you'll see that the sticks aren't parallel. Test at several points on the board. Take down the high spots, working across the grain or at 45 degrees to it, until your sticks are pretty well parallel. Now switch to an iron with much less camber (all but unnoticeable camber is OK, in my experience; I've never managed to sharpen an iron dead straight, so I don't know what "no camber" looks like), and plane along the grain until the face is smooth and flat.
Try it on a chunk of scrap first. Getting everything right without overshooting the mark takes practice.
>For larger panels or table tops you will also need a straight-edge. Well, call it a 'straight-enough-edge' when working with wood. No need for machinist precision here. I just use a long aluminum bar. A long level will work fine.
The straight-edge is used in conjunction with the winding sticks to find the high spots. Test for flat diagonally, lengthwise and crosswise. Mark the high spots and plane them down. It's a bit of a juggling act to eliminate twist and keep the work flat. Practice helps.
Darrell
Wood Hoarder, Blade Sharpener, and Occasional Tool User
>"I am making an small table top. It is approximately 42" long 20" wide. It is of Cherry and all goes well so far. Mostly done by machine. Jointer to remove cup and twist on one face on boards 6" or less wide. Then down to a hair above desired thickness on planner per board."
If you are within a hair of the final thickness, you don't have the material to go back to winding sticks. Also I don't think you mentioned thickness, but a fair amount of your woest nightmare will come out when you fasten the top to the base. If the top is rather thick, then you should be able to get the pieces to align well during the process, or at least it is fairly easy.
"Next glue up two boards so I can run that through the planer to clean it up. There's the hangup for me."
You can run into problems in this machine step, if you have a lot of narrow boards with a bit of V at the joint, and they are too tightly spaced to flatten when installed yet they pop up after being run through the planer. That is, though, one of the main things you would be on the lookout for, in the whole assembly process probably something to eliminate prior to joining.
"I am sure there will be a less than a true flat surface after glue up. just running it through the planer won't fix that."
Well it should if you did a fair job, and left enough meat on the boards. I often try to get too much out of the stock I choose and am really pressed to get the finished dimensions I am after, I should know better. I like hand planing the edges, which pretty much eliminates out of angle joints, one way or another. The jointer works for this also. Normally all you need to get rid of is a hair of misalinement if the boards slid to one side during glue-up. There are a bunch of ways of avoiding that. The best way with glues like the white and yellow, is to pre-tension the joint under about 20% pressure (must close joint though), give it a bunch of seconds for the excess glue to disperse, then apply full pressure.
>Thom writes "if you are within a hair of the final thickness, you don't have enough material to go back to winding sticks." For this size panel, 20 X 42, I think 1/8 inch over would be the minimum extra thickness you would want at the time of gluing the boards. A little twist, a little misalignment, a little bit off on your squaring of the edge, a little bit of cup- these things can add up and use up 1/16 of an inch in a hurry in a panel of this size. For a beginner 1/8 might not be enough. It is no fun to get a nice large flat surface and then realize that one area no longer has the hoped for thickness.
Some people think they will flatten the boards perfectly and joint the boards perfectly and align the boards perfectly and then when they glue them together all will be well. In reality, small errors in all these areas add upon each other. It is nice to have the extra thickness to take care of it.
