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View Full Version : Removing twist of (very) long boads?



Augusto Orosco
04-08-2013, 6:15 PM
I am starting the build of my Roubo workbench. I got some DF 12x2 sixteen footers that have been stickered and acclimated in my shop for the last 5 months or so. I ripped a couple of boards to 4.5 inches wide and cross cut them to 7 feet length to start the lamination process for the top. Unfortunately, I am facing much more twist than I hoped for. Yesterday night, I tried my hand at one of the boards and started with winding sticks on the two far ends of the board. With my scrub set to a very heavy cut, I removed the high spots on the first 12" of the two opposite corners at each end of the board and then moved one winding stick closer to correct the twist on the next 12". I left the other winding stick where it was and did not touch the area anymore with the planes, since I imagined I needed to keep one side as a reference for everything else, otherwise I would mess up the previously 'de-twisted' sections. In this fashion, I went on removing the twist along the entire board. I then identified the high spots with a straightedge and removed them with cross cut passes with my number five. Finally I started with full length passes with the five and finished with my No 8.

Making it (reasonably) flat on one face after removing the twist was easy, but getting rid of the twist was a lot of work and required constant checking (unfortunately, a few times I went too far, which forced me to compensate on the other side, with the corresponding loss of width). I have read about how to remove twist on boards, but never found anything specifically addressing long boards such as these. Are there any special considerations/tips for long (and not too wide) boards? For instance, was my decision of 'anchoring' one of the winding sticks on the far edge and not remove any more wood on that side after the first step a good one, or should I have done it differently (like trying to remove the twist at once by moving consistently along the entire diagonal?)


P.S. How would you decide if the twist is just too much to even bother? I am using 36" winding sticks and they do a great job magnifying the twist... so great that makes me wonder if I am just dealing with a board that is simply unworthy: To my untrained eye, I estimate twist of a couple of inches at the end of the 36" winding stick (which is balancing on center). This is my first attempt at flattening anything by hand, so I have nothing to compare it to.

Russell Sansom
04-08-2013, 9:41 PM
Augusto,
To answer your post script question: You can simply shim one winding stick (right under where it meets the edge of the board ) until the two sticks are parallel. I believe it was Derek who suggested feeler gauges, but you can use wedges, slips of card, etc. The thickness of the shim is the "amount of wood you need to remove." I put the last phrase in quotes because it may not exactly work out that way, but it should give you an idea of how much wood you have to remove on the two high corners ( combined ). If you're using long sticks, don't think about the difference between the end of the far stick compared to the end of the near stick. The thickness of the shim is the answer you're looking for.

Jim Matthews
04-08-2013, 10:33 PM
Seven feet?

I think you might want to resaw the most twisted examples and reglue with the grain opposed.
That should cancel the worst boards. I wouldn't try to do too much until the bench top is fully assembled.

There will be some mechanical fixtures, helping hold the top flat - won't there?
It would be unusual for even the most unruly lamination to lift the feet off the floor.

Augusto Orosco
04-08-2013, 10:43 PM
Augusto,
To answer your post script question: You can simply shim one winding stick (right under where it meets the edge of the board ) until the two sticks are parallel. I believe it was Derek who suggested feeler gauges, but you can use wedges, slips of card, etc. The thickness of the shim is the "amount of wood you need to remove." I put the last phrase in quotes because it may not exactly work out that way, but it should give you an idea of how much wood you have to remove on the two high corners ( combined ). If you're using long sticks, don't think about the difference between the end of the far stick compared to the end of the near stick. The thickness of the shim is the answer you're looking for.

That's a great tip! Thanks, Russell (and to Derek).

Phil Thien
04-08-2013, 10:49 PM
I'm not a hand-tool guy, but I thought I'd made a suggestion based on a method I use with corded tools.

This is my planer sled:

http://www.jpthien.com/ps.htm

What if you made an 8' long sled (a piece of plywood) and use some hot melt glue to glue your DF board down to the sled (using the masking tape will allow you to get your board to release easily). Use the same method I'd use, pretend you're going to run it through the planer.

Now, use a height gauge to find the lowest spot on your board relative to the top of the "sled." Transfer this mark around the perimeter of your DF board. Now plane off anything above your mark.

John Coloccia
04-08-2013, 11:07 PM
On the rare occasion that I do something like this, I put the board on my bench and shim it until I have it as flat as I can get it. Flat in this case means that if it were magically squared off top and bottom, I'd get the maximum thickness. Then I scribe a line around the top indexed off my bench. For example, I'll measure up 1" from the bench in a few spots, connect the dots, and plane down to that. Having a line to work to makes the process pretty simple.

edit: just saw Phil's post. Essentially the same thing as what Phil is suggesting. Put those winding sticks away until you're fine tuning.

Augusto Orosco
04-08-2013, 11:14 PM
Seven feet?
I think you might want to resaw the most twisted examples and reglue with the grain opposed.
That should cancel the worst boards. I wouldn't try to do too much until the bench top is fully assembled.

There will be some mechanical fixtures, helping hold the top flat - won't there?
It would be unusual for even the most unruly lamination to lift the feet off the floor.

Unfortunately, I don't own a bandsaw; and I'd imagine that resawing a 7' board 4 inches wide would be way more work than removing the twist with hand planes! :D


I'm not a hand-tool guy, but I thought I'd made a suggestion based on a method I use with corded tools.

This is my planer sled:

http://www.jpthien.com/ps.htm

What if you made an 8' long sled (a piece of plywood) and use some hot melt glue to glue your DF board down to the sled (using the masking tape will allow you to get your board to release easily). Use the same method I'd use, pretend you're going to run it through the planer.

Now, use a height gauge to find the lowest spot on your board relative to the top of the "sled." Transfer this mark around the perimeter of your DF board. Now plane off anything above your mark.

I recall your planer sled thread (as well as Glenn's sled, too). Your idea It's an ingenious extension to hand-tools!

Jim Matthews
04-09-2013, 8:11 AM
Unfortunately, I don't own a bandsaw; and I'd imagine that resawing a 7' board 4 inches wide would be way more work than removing the twist with hand planes! :D Fair enough. Having encountered just this kind of problem, I purchased a bandsaw. I believe resawing and boring lots of holes are why apprentices were in cabinet shops. They're also valid reasons to employ electrons (and the inestimable Jim Tolpin concurs).

Augusto Orosco
04-09-2013, 9:44 AM
Fair enough. Having encountered just this kind of problem, I purchased a bandsaw. I believe resawing and boring lots of holes are why apprentices were in cabinet shops. They're also valid reasons to employ electrons (and the inestimable Jim Tolpin concurs).

Don't get me wrong, I agree with you and I do lust after a nice bandsaw; it's just not in the cards right now!

David Epperson
04-09-2013, 11:46 AM
Might apply, might not. But I had a large piece of Bradford Pear I was making a platter out of - 24"x18" or so 7/8" thick flitch cut. I had the oval cut and was about to start on the hollowing. It developed a good bit of twist, which made the hollowing idea a lot more difficult. I didn't have anything to lose, so I layed it on the table saw, bowed side up (high in the middle), and put a damp paper towel along the high "ridge" and covered that side with aluminum foil. By the next day it was flat again. I left it alone for several months just to see how long the bow/twist would stay gone. Very little has tried to come back. Now that the weather is improving, I might get to finish that platter this year.

David Weaver
04-09-2013, 11:50 AM
Don't get me wrong, I agree with you and I do lust after a nice bandsaw; it's just not in the cards right now!

IF you had a good rip saw set up for softwoods, you could probably rip a 7 foot 2x in about 5 minutes. Pretty easily. But, you'd have to have a rip saw set up for softwoods and with coarse teeth, and there would be few times you're going to use something like that in the future.

I would hand rip before I would plane, but in reality, I would just spend the money to build the bench with whatever the medium hardwood du-jour is that's on sale at your local yard. If it's ash because of emerald borer, that would be it. If it's soft maple, then that would be it.

Augusto Orosco
04-09-2013, 12:15 PM
IF you had a good rip saw set up for softwoods, you could probably rip a 7 foot 2x in about 5 minutes. Pretty easily. But, you'd have to have a rip saw set up for softwoods and with coarse teeth, and there would be few times you're going to use something like that in the future.

I would hand rip before I would plane, but in reality, I would just spend the money to build the bench with whatever the medium hardwood du-jour is that's on sale at your local yard. If it's ash because of emerald borer, that would be it. If it's soft maple, then that would be it.

I am ripping before planning (up to 4.5 Inches wide). Jim was talking about re-sawing the board and flip it to reduce the twist. I am using a circular saw and a guide for the ripping.

You think this dimensional DF might not be worth the trouble? I was trying to be careful buying the longest and widest boards I could find; made sure it was kiln dried and let it sit stickered for 5 months under controlled humidity so it would finish drying properly. Now that I am ripping it, I am finding it's certainly a far cry from the quality you get when you buy hardwood at the lumberyard. More knots than I care for and bows and twists everywhere (not all at the level of this ugly board I am talking about, but twist nonetheless). This is my first "real" project, so I was trying to be frugal to avoid messing up good wood throughout my learning curve... (and it's a workbench, after all!). Maybe I am being penny wise? If appropriate powered jointers and planers were available to me, I would not be second guessing myself, but with only hand-tools, maybe this is too much to chew for a newbie.

Yesterday night I went and simulated John's and Phil's advice on how to tackle the twist. The layout made it look much more manageable; but doing 20 or so of those boards is a little daunting. Or instead, I can take it as a Wax on/Was off type of training in order to become a ninja galoot! :p

David Weaver
04-09-2013, 12:30 PM
Yeah, no resawing of the boards. Even on a BS. I'd cut them shorter lengths first.

You can eventually manhandle that lumber into something, but keep your eyes open on CL and other places for used hardwood lumber or something that could be repurposed.

I went cheap early on with lumber, it ended up being frustration. The last load of lumber I lucked into was 200 feet of QS beech and QS/rift cherry. It's like working in a dream.

I've picked the boards that look closer to rift/qs at the local borg, but the problem with a lot of them still is even if the orientation looks good on the end, the boards were not sawn straight up the grain on a tree, and there is twist in the grain, so the boards end up with twist despite looking QS on the end. They're better than nothing, but I think the route I owuld take with those DFs if I were you is cut them to short lengths until they were short enough to need little adjustment. That just presents other problems, though.

Jeff Duncan
04-09-2013, 1:39 PM
Two important questions I didn't seen addressed in your post....(maybe I missed them?), are you gluing up faces or edges on this project, and how much twist was there over 7'? I'm sure there's a formula for figuring out the twist over a 4-1/2" piece magnified by the 36" winding sticks....but Im not that bright;) If your gluing up edges, why are you ripping them first? I'd have either kept the full width, or bought narrower stock. Wider lumber is more expensive so not generally your best bet to buy large and rip down. If on the other hand your gluing up faces to get a nice thick top, they don't need to be perfectly flat. As long as they're fairly reasonable and you have 2 clean parallel faces for the glue line the minor twist is not a problem. Major twist could be problematic, but that kind of twist would not be practical to remove from the size stock your using as there would be little left.

good luck,
JeffD

Augusto Orosco
04-09-2013, 1:46 PM
Two important questions I didn't seen addressed in your post....(maybe I missed them?), are you gluing up faces or edges on this project, and how much twist was there over 7'? I'm sure there's a formula for figuring out the twist over a 4-1/2" piece magnified by the 36" winding sticks....but Im not that bright;) If your gluing up edges, why are you ripping them first? I'd have either kept the full width, or bought narrower stock. Wider lumber is more expensive so not generally your best bet to buy large and rip down. If on the other hand your gluing up faces to get a nice thick top, they don't need to be perfectly flat. As long as they're fairly reasonable and you have 2 clean parallel faces for the glue line the minor twist is not a problem. Major twist could be problematic, but that kind of twist would not be practical to remove from the size stock your using as there would be little left.

good luck,
JeffD

I plan on gluing faces to get a ~4" thick top, hence the ripping. I didn't measure the twist of that particular board, but now that it has little twist left, I have about 1.125" thickness left (out of the 1.5" I started with!). I hope the remaining ones are not that bad!

Pat Barry
04-09-2013, 2:30 PM
I agree with Jeff. I think you can simply laminate a few together at a time and in the process they laminated structure will straighten out. The only thing I would do would be to clamp to something that is straight as a reference point. After you get a few laminated the whole set will be much more stable. Then you work a bit on whatever twist is remaining before proceeding to laminate the rest of the pieces. Again, maybe its just me, but I prefer to laminate in stages and not try to do too much at one time.

Bob Black Atlanta
05-05-2013, 12:54 AM
Couple of thoughts. In my part of the country kiln dried framing/construction lumber is just one tick shy of dripping wet. Yours might be better but a moisture meter might scare you badly about kiln dried dimension lumber. My first bench was face jointed 2x4's face glued. It was 8' long. I put 5 pieces of 3/8" all thread through the middle with counterbores for the nuts that were big enough to get a socket in. I kept tightening the through rods for 5 years as the lumber dried and shrank.

Adam Cruea
05-05-2013, 6:33 PM
I just made a bench out of hickory. . .3" thick top.

I didn't worry about any twist in boards. All I really did was knock the sides down enough to get to virgin wood (remove the sawyer's bandsaw marks), then glue up like that. If you've got the grip, you can tighten down clamps and use culling to remove any twist/cup. After you get the top all glued up (mine was 33.5"), then get any twist out that may be there. Chances are, though, there won't be.

Keep in mind, I didn't view my bench as a work of art; just a functional piece that will end up getting dinged, scratched, and beat up.

Paul Incognito
05-06-2013, 9:42 PM
The easiest way I can think of to remove the twist is to load the boards up in your car and bring them down to Delaware. My big jointer is up and running and between that and the planer, it wouldn't take more than an hour to get everything flat and square.
Paul

Augusto Orosco
05-07-2013, 9:40 AM
The easiest way I can think of to remove the twist is to load the boards up in your car and bring them down to Delaware. My big jointer is up and running and between that and the planer, it wouldn't take more than an hour to get everything flat and square.
Paul

You are always so generous, Paul. Glad to hear that monster of a jointer is operative! I am in hiatus again (as usual, family and work leaves little shop time), but I'll get back to this top soon, I hope!