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I'm just getting started on resawing backs/sides. I built a solid fence with spring and roller system to press the wood into the fence (ideas from Shane as well as Edward Taylor in viewtopic.php?f=10101&t=28937 ). Pics shortly. The saw is an Agazzani B20 with Woodmaster CT 1". All that equipment is working great. But I don't yet have a jointer, planer, or wide-belt sander--currently I'm using a shop-built drum sander (with a pretty flat melamine table) to prep the face that goes against the fence. I'm planning on getting more equipment but still not sure what would be best (advice welcome). The goal is to prep 40 backs/sides for a class I teach in the Fall.

Here's a method I've tried with reasonable success (practicing with 4/4 S3S oak and walnut, about 0.8" thick)
1. If the board has twist, I hand-plane the opposite corners so it can sit without rocking. If board has a little bow, I plane the ends of the concave side to get the worst out. If it has a lot of bow, I leave it.
2a. If the remaining bow is < 1/16" (or board is ~thin) I drum-sand alternate sides of stock until both are smooth/flat.
2b: If bow is > 1/16" (and board is ~thick) I put the convex side on the table and just sand the concave side smooth and "flat" (it still has bow, of course).
3. Use the roller system to press the sanded/concave side flat (EDIT: that only works with lower stiffness woods, or thinner than ~3/8") against the fence and resaw 1 slice. I'm currently slicing at ~.135"... hope to reduce that a bit more to minimize later sanding.
4. With drum sander, sand the sawn face of the stock "flat" again.
5. Repeat steps 2-4 for remaining slices. At around 3/8" thick, bowed stock is flexy enough for sanding on both sides, so I do that.
6. Drum sand all the sawn faces to final thickness. Currently I'm getting 5 panels out of .8" thick stock, 6 out of .9".

Some questions for the experts...
- Any suggestions on the method?
- Is it ok to resaw backs from a somewhat bowed board (say, 1/8" over 24")? I know sides will get bent anyway, but I'm not sure if the backs will straighten out during stickering, or if problems will show up in the finished guitar. Do you have better ways of dealing with bow?
- I've guessed that it's best to flatten the stock after each resaw pass, but I've not tried it the other way (just keep resawing)--preferences, pros/cons?
- How much would a jointer help the process? I think I've looked at every option < $3k, but am struggling with the tradeoffs. What is (or isn't) working well for you?

Thanks for any and all advice!

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David Malicky

I take it you are resawing dry wood, my advice would be different if you were resawing large chunks of green wood.
I suggest after tuning your saw and setting drift angle you wax the blade with a candle without cutting your finger off. Wax the table and fence you have built.

Make a flat shim the thickness of the slice you want plus the thickness of the blade kerf.

Set your fence so the flat and square side of your wood is against the fence so that the cut you make will be the desired thickness of your slice and the bulk of the wood will be between the fence and the blade.

After making cut place a squeeze clamp on the rod your fence slides on and right up to the fence.

Loosen your fence and use your shim that equals the desired thickness plus kerf to space your fence that much smaller and make another cut.

Repeat this process until your board is too thin to work.

You are using your fence as you would if you were using a driftmaster fence. You must take care using this method to keep your hands away from the blade. You can make a very wide push stick with handles or use your roller system for safety.

Using this method you don't have to reflaten the wood

The disadvantage of this method is you need to get your billet flatter first. A jointer is very nice to flatten billets but you can do it pretty well by making a plywood sled for your bandsaw.

The advantage is you don't need to reflatten

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http://goatrockukulele.com

A jointer is a huge help. Not a must but it sure makes life easier.

If you are sawing dry wood, it will often cup as you saw due to case hardening. One way to minimize that is by sawing from one face then flipping the board and sawing from the other face. That usually equalizes the stress and and keeps it pretty flat. For that, you obviously want to start with a board that is flat and parallel.

Do you have a planer? Some people make sleds for their planer as a way to flatten stock. Some look pretty safe, others look like a disaster waiting to happen. The idea is that you shim the board on the sled so it doesn't rock then run it through. You could probably find some by searching at sawmillcreek.com.

Another method is to make a sled for the bandsaw but making a good one is a pretty big job.

By the time you get it all figured out, you will know why guitar wood is so expensive

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http://www.chassonguitars.com

Thanks for the advice! Michael, yes, dry wood. Wax is a good idea--those ribbed tables are supposed to have less friction but I'm not finding it for narrow stock. That method is clever! I don't know how well it would work with my setup, as my fence isn't clamped to the main fence, and needs to be carefully clamped to the table. I can give it a try, though.

Kent, thanks for the explanation and advice on cupping. Timely, too, as yesterday, I resawed some QSWO which did that and I didn't know why. The flipping technique sounds smart--will do! That also says I need a jointer, as I can't drum-sand the convex side of a bowed board. Hmm... I suppose I could attach a convex spacer to the drum-sander table, but that's some work to be precise. I don't yet have a planer, but will probably get one before the Fall. I like the planar sled idea, but thought it would be time-consuming to set the spacers and cutter height, especially for truing up a face after each resaw pass. Yes, I'm understanding more why sets are $$, but it's (so far) fun to make them!

Below are some pics of the setup. Fence is phenolic-faced BB-ply (slippery). The arms didn't have to be aluminum, but it's light and stiff. The total compression from the rollers is 20-25 lbs with the current spring. Mounting the rollers to the fence keeps the forces internal, so the fence isn't pushed over one bit with a stiff spring. It also makes a good blade guard, and keeps the table clear. Thanks to Edward Taylor for the idea! Last pic below shows a closeup of the rollers.


The resaw fence registers off the stock fence using 2 adjustment screws for drift and slice thickness (the nearer 5-star handle is easily visible, the back one hard to see). The fence's vertical angle is set by the 5-star handle pointing towards the table. The resaw fence is clamped to the table fore and aft from below (not in pic).


A view from the back, re-resawing some too-thick sides I bought a while back. For sides, I'm now trying slices at 0.110"... so far the saw marks are gone with 0.010" sanding.

Close-up of the Delrin rollers. The aluminum cylinder pivots about its center, and each roller can pivot ~10 degrees about its own center (the axle contacts are made sloppy and only 1/4" long). Each roller contacts the wood at its top and bottom. For an 8" board, this spreads the spring force into 4 equal points (kindof like a windshield wiper). For a 5" side like shown above, the upper edge gets more force, but that's fine. The 4 point contact and 25 lb compression work great for keeping the board on the fence as the board gets thinner and thinner, but it doesn't flatten an 8" warped board thicker than ~3/8". So I need a jointer. The little horizontal screw/nut just above the bottom roller is for stock that only contacts the bottom roller--I screw that in to keep the aluminum cylinder from pivoting, and all the force on the bottom roller.


Fun to make! Now which jointer?

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David Malicky

Nice rig. I can think of a few hundred times where I could have used it.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Don, glad you like it.

Does anyone use an 8" jointer for prepping 8 1/2" backs? I'm wondering if there is an easy way of dealing with the extra 1/2". I've never used a jointer so don't really know how well the different options would work. Grizzly's 8" helical head otherwise seems like the right level for our shop. A 12" HH jointer seems overkill for our needs, and $$, but if it's clearly the right choice we can probably get it. Or there are the smaller straight blade options -- Inca and Rikon 10". How much improvement in tearout do the helical heads provide?

Thanks for any advice.

Oh, after I made the roller setup, I realized I could have probably used a ~narrow skateboard end-truck, and wide wheels. I'm not positive it would work, but seems promising for less work.

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David Malicky