Not properly, and with no way to select how the knives address the grain.
Jointing half of one side and turning the board to face joint the other is simply not the same as properly face jointing the whole board.
Barry
Well, a couple of things to consider:
- Usually, 12" wide boards are either not available, or only at a serious premium, or crap. This is not always the case, though; you might have a sweet deal
- Boards that wide are going to be a lot bigger PITA then you might think, *especially* for shelves *if* those shelves are not in a dado (eg adjustable shelving). You will joint an plane them, put them in the bookcase and they won't be flat anymore. Wide boards are a non trivial exercise to work with. I am willing to bet that in quite a few cases, that shelves only sitting on pins could be jointed an planed several times over quite a few days before they stay totally flat on their own.
It is an awesome price, especially if it comes 12"+ wide.
How are you attaching said backs? Solid wood backs can be .... troublesome in the long run if they are fully glued on. Or even medium run.
PK
I'm not sure what you mean by "the planer has enough work to do just feeding and cutting a wide piece of hardwood". Removing the cup is certainly no more strain on the planer--just a couple of extra passes, at less than full load. Before passing on this approach, I strongly encourage you to give it a try, even if on a junk SPF 1x10. Particularly if cup is what you are dealing with--that is the easiest form of warp to fix on the planer, IMHO. That is because your "sled" doesn't need any rigidity along its length. A 12" MDF shelf from the Borg is perfect for this. Just put your board on the carrier MDF, concave side down, with a few spacers under the center (I'd run 1" wide stock 1' long through the planer to get just the right thickness, and put a spacer every 2' or 3' of board length, with each spacer milled to the right thickness for its location.) Run this "package" through your planer, taking light cuts near the end, until it is planing full width. Then flip and plane the other side w/o the sled.
Then sticker it and wait to see how much bow returns, possibly in the opposite direction. Then repeat. Or get it locked into the structure of your project.
The second paragraph applies no matter how you remove the cup from a wide board. And to a lesser extent, any warpage. Someone else here mentioned that if you don't have structure to keep the cup out, it is likely to return, even if the wood is perfectly stable, just due to seasonal movement.
IMHO, this is good advice. smaller pieces mahine much more accurately. Suppose you have an 8' board from which you want to make 3 30" shelves. milling an 8' board flat and straight is actually quite tough (unless you have pretty large equipment) and you will loose alot of material to a bow or twist. Rough-cut to 32" and it's a snap on modest equipment and you will have minimal loss of material.
This concept even applies to chopping up plywood. Full sheets are hard to manage and can drift off slightly off course if they are not really well supported.
BTW you can cheat and push your board through the planer for a light pass before flattening to help you see what's going on with the grain.
-Steve
Common practice, not cheating. It's called skip planing or hit and miss planing.
Charlie Self "One of the common denominators I have found is that expectations rise above that which is expected." George W. Bush
Dear OP
At the risk of prolonging this thread, the 12" jointer referenced above is $3800.00. If you assume that you could have your wood supplier dress your wood for $1/bf, you could make 3800 ft of shelving before paying for the jointer, neglecting the cost of the power. Of course, you could probably get that wood dressed for MUCH less than $1/bf. 4000ft of shelving is a LOT of shelving unless you are making it for sale.
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