HELP: Problem surfacing rough lumber

I'm looking for some help with a problem I've been having. Through the years I've managed to acquire a planer (ridid 13") and jointer (Delta DJ-20). I've been working with oak lately which I've been buying rough from a good hardwood supplier. To surface the stock I've been cutting it to rough width and legnth. Then I fact joint one surface until it's flat against the jointer bed. The next step, from what I understand is to run the board through the planer, flat side against the bed (down) and plane the board to desired thickness, in this case 3/4". For some reason after I plane it, i put the board down on the jointer bed again and I find that neither surface is flat. For the life of me I can't figure out how this can happen. From what I've read the jointer, and your form, is the biggest source of problems, but once i've found the face to be flat, it should be fine. It doesn't make sense to me how the planer could bow the stock. I've checked the planer and found it to be set up properly (so I think), but even if not, it should only affect the surface being planed, not the other side.
Now, the bow is minor, and with a little pressure i can easily hold the board flat, but I am thinking that it still shouldn't be this way. The only thing I can think of is the board reacting to internal stresses as the supporting wood is planed off, but it keeps on happening across several boards.
I've taken up this hobby to relax me, but at times like this is is anything but. Can anyone shed any light?
Rob
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Sounds like the wood is reacting to internal stresses. If it is bowing immediatley, then it has to be stresses in the wood. Is it flatsawn stock? I have found flatsawn wood which is more from the center of the tree to be highly prone to wander around like this. Why don't you try some quartersawn and see what happens. Some folks recommend taking equal amounts of stock off of each face to balance out any moisture in the wood. I usually don't do this. What is the moisture content of the wood? Is it kiln dried or air dried?
Frank
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news:AusXc.13738

When I reread this I realized that I had misworded this. I meant that flatsawn wood is more prone to wander and the closer it was taken from the center of the tree the worse.
Frank
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<snip>
So, maybe it's technique.
Once you get side one face jointed, it becomes the reference face for the planer operation. Run the board through the planer until the side opposite the reference face is smooth. It may not yet be to thickness, but the two faces are parallel.
This is a good place to let the board take a rest. Maybe for a couple of hours, or maybe a couple of days. Stickered, with air flow, in the shop environment. Let it adjust to being something less than it was before the machining. (Sit down, and watch those TiVo recordings of Olympic Synchro Diving, if you must...;-)
When the wood has adjusted, and all of you stock is milled to rough size, then complete the process. This time, turn the boards as they go through the planer, taking approximately equal amounts from each face, taking into account cleaning up tear out, or color, or whatever. With oak, it's also a good thing to maybe turn those TP1300 blades over first, and get a nice sharp edge.
You CAN beat the wood into submission. It just won't be happy about it, and will subtly try to ruin your enjoyment of your time in the shop. Those nice tenons won't fit like Norm's do, on TV, and the mortises will be ever so slightly in the wrong place. But then, you don't likely have a team of production assistants making sure everything is just so, either.
The good news is that woodworking is so much less stressful without a producer and camera crew watching everything you do. And nobody is recording the 'magic words' invoked to get things to fit, either.
Enjoy your shop. The time there is precious.
Patriarch
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Rob, I've just been dealing with jointer/planer adjustment frustrations. The height of the outfeed table, after a week of cursing at my jointer, was my biggest challenge regarding flattening the wood. I'm not sure which way it goes, but a high outfeed table causes a convex or a concave board. A low outfeed table causes the opposite either way. If the infeed/outfeed tables have a sag, even if it's very small, it can be very, very frustrating to get a straight board. Jointers are tricky to use at first, there is more technique than I imagined. I have been practicing with cheep 2x4 fir/pine, it's easier to joint and nicer on the blades, watch for staples, pebbles etc. A good book by John White is "Care and Repair of Shop Machines." So far, with a few modifications on his techniques, its been a great book. Keep us posted, and let us know of your solution.
Don

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