Surfacing Thin Walnut Boards
What's an efficient way to re-saw and plane (or sand) quarter-inch thick boards? Pros share tips and techniques for reliably achieving a smooth surface. June 20, 2005
Question
I have a 24" verticle bandsaw. I've got a buyer wanting all the black walnut I can deliver, as long as it's between 12 and 20" long, and 1/4" thick and air dried.
I've got a local source for air dried walnut that's 4/4 and 6/4 that I'll use for my source material. I was wondering if anyone has any suggestions on what blade to use? Also, should I re-saw it to 3/8", and then plane them down 1/8" on each side to get the final 1/4" of thickness needed? Any help would be great.
Forum Responses
(Sawing and Drying Forum)
From contributor G:
I would recommend re-sawing them a little thicker, but I wouldn't try to plain them to final thickness. If you hit a little knot or cross-grain that would normally cause tear-out in a thick board, it will usually tear a hole in the thinner stuff. Run it through a wide belt sander or else a good drum sander to reach the finished thickness. A drum sander would probably be better for accuracy, where a wide belt would be better for finish.
From contributor T:
To the original questioner: You didn’t say what level of finish the customer has specified. Since you have the ideal size saw for a Lenox carbide blade, get the Trimaster 1" carbide blade and see if the finish off the saw is good enough.
I have gotten a cut fine enough to go straight to 120 or even 150 grit sandpaper using the carbide on my MM16. It really is a huge difference in quality and since it is said the carbide blade prefers a wheel of at least 24" (because it is prone to fatigue breaks), you are in a perfect situation to use the right accessory.
From the original questioner:
To contributor T: My customer has stated that they are fine with a finish equivalent to that of a planer. Are you suggesting cutting 1/4" direct off the saw? I think the finish off the TriMaster may be good enough. Getting a stock feeder will probably be a must. I just felt that the Trimaster would take too big of a kerf.
From contributor I:
To the original questioner: How many boards are you expecting from each blank? I think it’s going to be cheaper to use the carbide than spend lots of time on sanding. Don’t forget to stack them to allow for cupping, as you change the stress pattern when you slice.
From contributor T:
You are going to have to figure out if you can cut to 1/4" in one pass without further finishing it, and seeing if they like it enough. Without a doubt it would be your most efficient method. It is clearly a goal worth experimenting to achieve. Put a planed board on the saw, make two or three passes, and find a good way to stack 3 or 4 finished products.
From the original questioner:
To contributor I: I don't know how many boards I'm going to get from each blank. It depends on the blade I go with. I think I'm leaning towards the Trimaster Carbide.
I also didn't realize that these may move that much when I re-saw them. I figured since they were air dry, they'd be stable. Are you saying I should sticker them as they come off my saw? Or should I dead-stack them, with weight on them?
From contributor F:
As far as the accuracy of wide belt sanders, I sand veneers on a timesaver wide belt sander and have had perfect results. I have a re-saw bandsaw in my shop and if I had your job, I would first run the face of the blank over the jointer to establish grain direction and flatten it. Then label the end of the blank to indicate which end to feed in to the planer. Re-saw the pieces with the best setup you can make (I like a rack of feather boards and a stout fence).
After you saw one or two, you will figure out how much oversize you need to saw them to plane out the saw marks. Put a melamine auxiliary table on your planer bed - this will curtail the end snipe caused by the bed rollers (thinner stock especially).
From contributor F:
What I do to package that type of product (instead of dead stacking, stickering, etc.) is as soon as I have enough pieces planed out to make a bundle, I wrap them tightly with shrink wrap at both ends (and in the middle if they are long) and then store them on a reasonably flat surface. As far as I am concerned, at that point you did your part. It is up to the end user to keep them from cupping, etc. while they do their part.
From the original questioner:
To contributor F: You don't get much movement wrapping them that way? I'll give it a shot, as it sure seems to simplify things.
From contributor F:
To the original questioner: Just from personal observation, the way to cup a piece of thin stock is to leave it laying flat on a bench for half an hour. If the micro climate (shops) is dry, the thin stock will dry (and shrink relative to the other side) on the face that is up and become concave on that face. If the air in the shop is moist, the opposite will happen and the board will expand on the side that’s facing up and become convex on the up-face and hollow on the down-face.
The thinner the material, the faster it occurs. This is really apparent if you ever work with veneer. When I am using thin material on a furniture project, I use these to help me get the piece flat right at the moment I install the thin piece. Then, the restriction of movement by being glued to other stiff and straight cabinet members or air flow on both sides of the piece (stickering principal), which will keep both faces exposed to the same elements, will keep it flat (most of the time).
To get to the point at hand, tightly bundling the pieces immediately after sawing and planing (don’t delay) will keep all the faces moisture content equal. If you really want to do a super packaging job, cut some strips of an inexpensive 1/4" material the same width as your walnut and use them to sandwich the bundles. This is the best you can do. If the stock you are sawing bows badly right off the band saw, there is little you can do except to try and find some more stable material.
From the original questioner:
I also need some slices down to about .17" for my client. I tried slicing with my WoodSlicer, but I think the blade is too thin. There isn’t enough beam strength, so it tends to bow, and I'm getting flutter marks on my boards.
I'm going back to my Trimaster Carbide, and I’m going to see how accurate I can get. I know if I got a drum sander, I wouldn't need to be quite so accurate at the saw, as the sander would get me to any final thickness I need, so I really am leaning towards looking at a Performax 16-32.
From contributor F:
To the original questioner: Does this mean you didn’t try the method of using a jointer to establish grain direction before you re-sawed and planed to net size?
From the original questioner:
To contributor F: The wood I'm cutting thin right now has obvious grain direction. But running it over the jointer does indeed help. When I plane pieces that thin, the planer destroys them. I'm pretty sure I'll need to drum-sand to the final surface and thickness consistency.
From contributor F:
To the original questioner: Yep – it’s a pain when the planer starts kicking chunks. My planer can plane amazingly thin, somewhat less than .125 without blow-up. But I always use the jointer to check/establish the grain direction. (I have met a lot of obvious grain directions that lied to me). My jointer is way more of a pain about grain direction than my planer. So, if the jointer likes the grain direction, the planer really likes it.
