Hi – I have several dressed 5/4 curly maple boards about 9′ long that were recently resawn from 12/4 material. Some of the boards now have a 1.5″ bow the long way, i.e. when placed concave side down the center of the board is 1.5″ off the ground. The original 12/4 boards did not have any bow in them. I want to make a table from these boards and need to remove the bow. I will not plane them since I want the look of a thick table. The bow is medium strong, i.e. i can put 2 boards together concave face to concave face and squeeze the bow out of them with my hand. I have clamped the bowed boards together with a reverse bow for a few weeks hoping it would less then bow, but that has not really helped.
The only solution I can think of is to get a few 7′ or 8′ lengths of angle iron and screw them into each board the long way to get the bow out. I was also thinking of putting in saw kerfs into the boards about 1/2 in and across the grain to diminish the bowing pressure. Has anyone done this? Seems reasonable but then again, many things do but aren’t.
Some of the boards do not have a bow so I am thinking that when glued up they will help keeping the bowed ones straight. I will use plenty of biscuits between the boards. Any suggestions/experiences? Thanks alot.
Replies
Is your table going to be 9' long? If not, you will get rid of some of the bow in cutting the boards to length. 1.5" over 9' of bow sounds manageable with some clever glue up and LOTs of clamps (forget the bisquits, if you asked me). Try alternating the bowed board direction (onebowing up tha the next down etc.) and use the flat boards as well to get a decent table top glue up.
The table will be 9' long. As for alternating the boards, most of them have their best face with the concave side up. Some don't so those I will alternate.
Why are biscuits not so usefull here? I would think they would help alot aligning the boards.
How about the idea of using saw kerfs to make bending easier? Maybe it will relieve some stress in the wood also. What would be the down side of doing this? I don't want to use too many angle irons since 7'-8' lengths are hard to get and are expensive
Yurij,
You are the one standing there in the shop with the wood, so you know this particular situation far better than me. But if you can place one of the bowed boards on your bench and press down the middle so its face is flat without too much pressure, then I would think the bowing can be overcome in the glue-up stage. When gluing up my maple bench top, some of the boards were warped or bowed slightly, and these were quite easily addressed by clamping one joint at a time and bringing a lot of clamps/cauls to bear. Now twists or cupping cannot be dealt with in this way, but bowing and some warping can, in my experience. We've all glued up panels where some board has shifted since true up in some way. It's a fact of woodworking life. A nice clean bow over nine feet, seems like it should be manageable. But like I said, you are standing there with the wood, so likely have a better take.
I don't think the angle irons are needed.
Bisquits will not add substantial strength or aid in alignment significantly. Indeed, they may slow you down in glue up and even frustrate alignment is you use too many or misplace any even slightly. Instead just glue up one seam at a time and have cauls and clamps at the ready. You might also want to clamp it to a flat surface (e.g., plastic covered bench or work table) while gluing each seam so you are not just clamping the seam horizontally, but are simultaneously clamping the boards to a flat surface while the glue sets up.
If you really feel kerfs are necessary, I'd try using a very thin blade - maybe a japanese saw - and go not more than half the way through the most bowed planks at maybe 5 spots spread out across the few feet at the underside of the peak of the bow. I'd be disinclined to do this unless I really had to just because it will weaken the boards and look a mess (I know, only from underneath).
Let me add, in conclusion, that I am no expert, but rather just a fellow woodworker brainstorming with you here. I have done many glue-ups of various sorts, but that doesn't mean I'm any kind of expert.
Edited 12/12/2007 10:39 am ET by Samson
Samson - Thx for the suggestions. I was going to create the table one board at a time, but clamping the board to a flat surface first is something I'll consider. I do think I will have to put the kerfs in, there is some resistence in the bow and as it will be a dining table so 5/4 strength is not needed. Since the boards are about 5-7" wide, I think it will be hard for me to keep them aligned without biscuits. I don't have clamps that extend that far over to keep the boards in the same plane. Maybe I need to get something likehttp://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=39146but i'd rather not. -yurij
Just use cauls clamped with a couple of quick-grip clamps to keep the boards aligned.
I'd be leery of cutting kerfs in the backs of the boards--I have a feeling that the cuts would eventually "telegraph" to the top surface.
-Steve
I think it will be hard for me to keep them aligned without biscuits. I don't have clamps that extend that far over to keep the boards in the same plane.
Make yourself some cauls out of 8/4 stock. A piece of wide cellophane shipping tape stuck to the caul will keep any glue squeeze out from sticking to the caul.
I made a mess of cauls by cutting 3/4" ply about 3" thick and gluing them together to make 1.5" cauls. I then ran them through the table saw to make the surfaces flat. I covered the face that would be against the glue-up with packaging tape. They fo an excellent job of providing a flat reference surface and clamping the whole thing flat across. Or you could make them the full length of the ply sheet, giving you an 8' caul that would do most of what you would want for a 9' board.
How is a caul differnt than just using some 2x stock? And from the responses it seems I can use them to go accross the boards (to keep the aligned) and also along the board to flatten it during glueup. Pretty good ideas
"Caul" is just a name for a piece of wood that is used in this way just like a "batten" is a name for a similar piece of woodwhen it is used in another way.
Some folks will plane, cut, or mill their cauls to have a slight belly - a curve that is like 1/16th to 1/8th higher at the center than the ends. The idea is that when clamped at the ends, the curve helps develop an even pressure and accounts for the tendency for the pressure on the two ends to impart less pressure on the middle. In my experience, even flat cauls work very well.
You can make cauls out of whatever you like - 2x stock or glued up ply etc.
"Some folks will plane, cut, or mill their cauls to have a slight belly..."
If the purpose of the caul is simply alignment, as we're talking about here, then cambering them wouldn't have any useful effect, and would probably make it harder to get the panel absolutely flat, as the two cauls on either side of the panel would be fighting each other, and you'd have no control over which one would "win" over the other.
-Steve
I'm referring to the cauls that going across the edge joints - i.e., perpendicular to the joint, not those that the OP was talking about to get rid of the bow lengthwise.
The slight belly in such a case is intended to make sure that the pressure at the center (over the joint) is strong even though the force is being applied to the ends of the cauls. Sort of like tapers on vice jaws.
I generally find the glued-up ply to be cheaper, stiffer, and more stable over the years. Otherwise, no difference. PS: Also used up some material taking up room in the shop.
Edited 12/12/2007 1:38 pm ET by dherzig
First off, I have never made a 9 foot long table but many doors about this length with all kinds of woods. Custom doors for old houses that were thick.
If you have the time and patience make a steam box and clamp the sticks flat and if the stay flat.. You have something to work with!
I for one do not agree with alternating the grain up/down. I used all sticks with the curve edges UP.. You can plane it flat later.. Just a hump in the center if the wood chooses to do so.
Hardwood QS spines (or a quality plywood) the full length for each board and a few Dovetailed cleats across the width (underside) should hold most anything in place.
Just me... But what do I know?
I used all sticks with the curve edges UP.. You can plane it flat later.. Just a hump in the center if the wood chooses to do so.
Will, one of us is misunderstanding the OP. You seem to be describing a cupped board. OP is describing a bowed board. If all the bowed boards were edge jointed and glued up so the entire table top was 9' long and bowed up 1.5 inches off of flat at the center, given that these are 5/4 boards, when you planed out the hump, you'd have a hole in the middle of the table!
when you planed out the hump, you'd have a hole in the middle of the table! How about a cheese dip thing!OK you got me on that one!
WillGeorge - Steaming is something I definitely do not want to do there. I would have to get 10' plywood, etc... its difficult for me. And I also hear that it can introduce some (bad) color into the wood. I need to flatten the boards mechanically, I won't plane anything off. But thanks for the ideas. -Yurij
I'm surprised no one has mentioned the fact that the bowing occurred after you cut the board from 12/4 material. Some of the bowing is likely from unequal moisture on the two sides. I would sticker your newly cut boards for a few weeks and then see if most of the bow will come out on its own when the moisture has equalized.
OP said it had been a few weeks since they were cut in his original post.
While moisture differentials could cause bowing no doubt, I'm guessing that they bowed more or less right off the saw as the internal stresses of the grain were released upon resawing.
I was hoping that uneven moisture was responsible. But so far its been 2 weeks and I detect no real change. But it must that, otherwise the original boards would've bowed also. What if I wet one side to help equalizing the moisture? Might that help? Kind of like a poor man's steaming.
I wouldn't wet the board to try to correct a lengthwise bow. You'd end up trading a little bit of bow for a whole lot of cup.
-Steve
yuri, the bowing of the boards immediately after deep ripping is not caused by uneven moisture content per se. It's true that every piece of wood in normal circumstances has a moisture gradient. This means that wood has uneven moisture content throughout its thickness, and even length very often, as it adapts to ever changing conditions of RH.
Let's say that you've stored a piece of wood in a fairly dry environment for several months, eg, your house, and that average atmospheric RH over that period was about 42%. It would be reasonable to assume that its average moisture content after that period would be about 8%. The MC of the shell could be 7%, the intermediate zone's MC might be 8% and the core might be 9%. That's a moisture gradient-- wetter on the inside than on the outside.
Next, let's say you take that piece of wood at an average 8% MC and store it outside under a shelter for a month or two and that RH outside averages about 70%. The shell quite quickly starts to absorb moisture in an attempt to reach an EMC (equilibrium moisture content) with the RH. There's a time lag involved known as hysteresis that says that wood doesn't immediately respond to changes in atmospheric RH. The EMC of most timbers exposed to an average 70% RH is about 13.5%MC. The shell will reach this MC first.
Meanwhile the intermediate zone and the core are still drier because they're sheltered from the immediate rise in RH, but the moisture that's worked its way into the shell will gradually move towards the core. So after a suitable period of time the intermediate zone might have an MC of about 12% and the core shows 10% MC. That's another example of a moisture gradient-- wetter on the outside than on the inside.
Keep your piece of wood in unvarying atmospheric RH conditions for long enough and eventually it will reach an MC that is equal throughout its length, width and thickness. Except in artificial condition that never happens as RH changes weekly, daily, hourly, even every few minutes, so wood is always adjusting to suit.
Anyway, enough of all that nonsense; it's probably far too much information, and I didn't even get started on the topic. The reason why your wood bowed when you deep ripped it as you did is almost certainly because it's very slightly case hardened, a condition induced in it by the drying process. I'd be willing to wager a tenner that the resawed boards also cupped across their width with the concave face towards the centre.
Deep ripped case hardened boards don't straighten out either in the length or the width to any appreciable degree. They stay that way, and the bowing and cupping generally has to be planed out to get them straight and flat again; and even planing them offers no certainty that they'll stay flat and true because the stresses in the resawed boards remain out of balance.
Because I've drivelled on long enough already, and taken up far too much of Taunton's bandwidth, I'm afraid I'm going to leave it to others to continue offering solutions to your panel glue up dilemma, although I've got plenty of my own I could offer. Slainte.
Richard Jones Furniture
Edited 12/12/2007 3:48 pm by SgianDubh
SgainDubuh - The wood is definitely not cupped across its width. Only along its with. That said, I had the wood planed before I took delivery, so it might have cupped but they planned it out. It is not cupped now.
I need to mention that I was not present when the wood was resawn, so I don't know if the wood started to bow immediately, or took a day or 2. I understand that this would determine if the wood was case-hardened or not, and that if it was case-hardened then it will never straighten out.
Also, the wood was stored in an unheated outdoor building (the yard stores all its kiln dried wood there). the shed has lots of garage doors for access so the MC was probably whatever the outdoors is. Also, the original 12/4 wood was there for quite awhile before I had it resawn, so it certainly equilibrated. I knew that something like this could happen, but the wood is very nice and I took a chance. I will make it work out. Thx -Yurij
Maple is dense so 2 weeks is not enough time. If there is no appreciable change after a month or so I would have to then agree with Sgian and say its case hardening. I don't think there is a cure for case hardening. Think shorter project.
Or wide aprons to hold it flat.
Ben, there is a cure for case hardening, but not one that can be effected readily in the workshop. The cure involves sticking the material back into a conventional high temperature kiln, lots of steam and high temperatures. Slainte.Richard Jones Furniture
Thanks. I always thought that the case hardening cooked the lignin into a permanent set which was irreversible. I will have to re-read Bruce Hoadley, etc. Anyway, there's enough wood in the world without having to wrestle with a recalcitrant piece.
Yurij,
First point:
Do not listen to the anti-biscuit parade. They don't use biscuits, by their own admission, so know nowt about them really. There is mere prejudice in their heads, not experience. Some have used cheap biscuit joiners, badly, then blamed the whole biscuit thang - like heartbroken boys who never risk another girlfriend, they are. :-).
Biscuits do help alignment, especially with long, bowed boards as you describe. Cauls may work but they are large, awkward and not foolproof. It is all too easy to end up with a ledge between two boards here or there. Then you will be cursing and planing for some time.
Biscuits are fast, elegant and precise (assuming you have a decent biscuit joiner, biscuits and good technique in using them - all easy to get). I know because I have used thousands to help glue-ups. I used to use cauls too; but they were a pain in the erse and required acres of shop-room.
Incidentally, a Plano-press (vertical clamp for edge glue-ups, large and small) applies the caul principle in a neat and scientific way, should you feel inclined to spend the money on one. I love mine; it is currently full of large beech panels glued up from planks, with the help of a few biscuits to keep any bowed boards aligned as they go into Mr Plano.
When the beechers emerge, I know from experience that there will be a minimum of flattening needed - a swoosh or two with the jointer and a bit of a smooth - no great ledges or bumps to worry about.
Incidentally, biscuits do add strength too - not that any more strength is really needed in glued edge joints. However, biscuits also act as internal clamps, so you can generally take the external clamps off your glue-up well before you might without biscuits - should this be an advantage to you (ie to use the clamps sooner for the next task).
I am currently loading and unloading the Plano-press with beech panels at a great rate of knots, as the biccies keep things together after a mere hour or two in the press. (There are many panels, tops, shelves and dividers required for my current project).
Second point:
If you can make the boards straight with just a bit of hand pressure then your table construction will keep them straight, assuming you make enough flat surface to lay the top on.
In making a number of large tables I have come across this syndrome often. Four-legs-on-the-corners tables have four aprons to give a flat surface, which will keep the bowed-board table top flat, assuming the resistance to de-bowing is weak, as you describe. It is a bit harder with trestle tables but wide cross-arms and an under-rail immediately below the top can help flatten a trestle table bowed top.
With the 4-legs-corners table, you can put an additional cross-apron or two between the two longer aprons, as this gives even more of a flat reference surface for the table top to be attached to; and held down by. I dovetail mine into the inside faces of the long aprons.
Personally I wouldn't cut kerfs to help un-bow the boards. Depending on where the stress is that is causing the bow, you might even worsen it (although it will take less force to unbow them). It will weaken the top of a bit but will also spoil the planks, should fashions change and the table become the timber-source for a different piece of furniture.
I have used quite a few old bench and tabe tops as the source of good, long, thick planks for something else. It is annoying if they are filled with holes, screws, nails... or cuts.
Last point:
one easily unbowed board added to another and another....may make a not-so-easily unbowable top. It may be wise to alternate the boards bow-wise, assuming this doesn't interfere with your required grain patterns and such. There may still be an overall bow or resultant wonk, but one that is still flattenable by attaching the wonky top to the aprons......
Lataxe, the jolly biscuiteer.
Edited 12/13/2007 5:13 am ET by Lataxe
Lataxe - I too agree with you about biscuits. Like any tool they can make matters worse or better. I will use the biscuits (I have the dewalt tool), but I think I will glue up 1 board at a time to give me more control. The biscuits swell up too quickly for my speed.
Is there an article that describes any of the techniques you mentioned so I can see some pictures? I like the idea of additional width-wise aprons, but if I have to use the angle irons (because like you said, the sum of many easy bow's ='s a hard bow) then the interior aprons will get in the way.
As for the kerfs, I am still undecided if I will use them. Most of the faces that I plan to use are on the concave side, so the kerf's would be on the convex side. Does putting the kerf on that side make matters worse, i.e. I am cutting the fibers that are helping to prevent more bowing and I should be kerfing the other side? Someone mentioned that the kerf might eventually show through to the top. I am suprised about that since this technique is used all the time to produce curved lumber (I have never done it myself), and I have never read that it could cause such a problem. It would be nice to hear from someone with experience on this.
Thanks for all your comments and advice. -Yurij
Y,
Here are some old posts that may help a bit:
30379.1 is a set of pics of a large dining table with a cross-apron. Buttons on the underside of the top hold it to all the aprons and allow movement. The legs and aprons are very, very stiff because of the corbels and glue-blocks. Thus the underside would pull a wonky top flat (rather than the wonky top making the underside wonk as well).
Some other related posts on biscuits at least:
31220.17/19
33960.50
30647.31 has some pics of biscuits "half-loaded" into a panel, which shows that with careful application of glue/water, biscuits are unlikely to over-swell and telegraph or otherwise become unusable.
33960.28
34325.16 et seq
Kerfs:- When used to make bent pieces, the cut is made to near the show-surface but then the kerfs are closed together on the no-show surface to make the bend. Even so, the kerf depth and spacing is said to be critical, if flat spots, lumpy curves or splits are to be avoided. (I've never tried this technique myself because of its reputation as "difficult"; its steaming or laminates for me).
If you make such cuts then bend the board the other way (kerfs open) then one or more kerfs might try to open up too much - ie cause a split to work up to the show (top) surface of the table. After all, by kerfing then unbowing the board, you are stretching those fibres at the kerf-bottom (ie at the table top). A very deep kerf will allow most unbowing but also leave the least still-intact fibres.............
I have seen window sills and other wooden parts so-kerfed, to prevent bowing or cupping when they are subject to moist/dry cycles, so perhaps the technique is safe. But I feel that careful construction (alternating the bow in the top planks and buttoning the top down to a stiff undercarriage) is a safer option.
Lataxe
D,
You have forced me to admit it: Bicuits are indeed mana from heaven. As a hell-spawn forever denied this ambrosia, I endeavor to deny it to others. As Mr. Aesop said: sour grapes.
Actually, I have used biscuits many times. I have a Makita machine - middle of the road compared to Lamello, but not bad. I like biscuits for plywood carcase construction, and for face frames, and even in some light duty rail and stile door type applications. I've found them to be unnessary and even detrimental in various ways in the context in panel glue ups. Obviously, you have a different experience. As you say, it must be that my biscuit mojo is lacking. Despite some minor successes in other areas of woodworking, I am apparently a "lamello lame-o."
"However, biscuits also act as internal clamps, so you can generally take the external clamps off your glue-up well before you might without biscuits ... the biccies keep things together after a mere hour or two in the press."
Have you ever done a glue up without biscuits or a press? I do it all the time, and for most standard panel applications, I can take my panels out of the clamps within an hour or less, if I desire, without any ill-effect. As LV states - a 30-90 minute clamping time: http://www.leevalley.com/wood/page.aspx?c=2&p=45104&cat=1,110,42965&ap=1
Most any PVA is the same as far as reaching 80% or so of its strength in short order - i.e., when it sets as opposed to fully curing.
- S
Buck Private in the Anti-Biscuit Brigade
Edited 12/13/2007 10:19 am ET by Samson
Samson,
I agree that, in the best of situations where the wood is nice, one doesn't need biscuits to ensure a good edge-to-edge glue-ups. However....
When the boards are long, with some bow and also the deliberate small dips planed in their middles, one likes a biscuit or three as a sort of belt-and-braces or backup clamp. In my shed the temperature sometmes drops, despite the background heater that is always on. I have been caught out by glue that has not quite set because of the low temperature.....
Also, I use a fair amount of reclaimed teak and iroko. Both of these rascals can be problematic glue-wise. Sometimes the oil seems to hunt down the glue to stop it working, just to annoy me! In such cases I have learnt that a lot of biscuits in the edge joins ensures no possibiity of separation, despite the oily gremlin. Them biscuits have mechanical grab.
All of the old chemistry benches I seek out (as they are often teak) have their planks edge-jointed with 1 inch wide, 1/4 inch thick splines. Their makers, too, were obviously wary of the teak-oil effect. Because their splines are solid wood and possibly made in the old-fshioned way, they are often loose here and there. They often fall out the groove when the tops are resawn (I saw along the old joins, then saw out the spline-inch, to get new solid planks.
In the worst cases, the joint has opened and the chemicals have seeped into the bench top. Happily the teak oil also laughs in the face of even the strongest acids and alkalis.
Whenever I resaw something with biscuits rather than splines, there is no loose biscuit in there. They are all tight and solid, because their technology makes a very, very good fit.
Viva la biscuite!
Lataxe, as jolly as ever.
If you can flatten the boards with hand pressure, then design the table with stretchers underneath.The angle iron will work, you may want to hide the iron with wood .Apparently the 12/4 stock wasn't dry enough.When you resawed it the stock bowed,
mike
Mike - I assume the stretchers would go the width of the table. How would I attach the table top so that it allows wood movement but would also flatten the board. I am afraid that it might bow the aprons using this method. The angle irons would not put any pressure on the apron. -Yurij
How would I attach the table top so that it allows wood movement but would also flatten the board.
I've attached a picture that hopefully speaks for itself. And here's a link to a prior post with a pic of some actual buttons (on amuch smaller project than your 9' table, but same principle).
http://forums.taunton.com/fw-knots/messages?msg=38153.15
I am afraid that it might bow the aprons using this method.
If the aprons are something like 7/8ths x 3" or more in cross section, they should be very rigid.
Edited 12/13/2007 10:53 pm ET by Samson
Samson - That is a good picture, thx I certainly need to button the top to the apron at the ends, but all the additional aprons make me think that the angle iron will be less work, as good, and easier to attach to the top. But considering the number of angle irons, it will cost $$. As usual time vs money.
yurij,
I've been lurking in this discussion taking in all the ideas and I have a suggestion. It's probably off the wall but here goes:
How about making a batten that is in the shape of an elongated X that would go across to each corner of the tabletop underneath? I'd make the X out of quartersawn material with a simple lap joint where it crosses and pin it there with the legs of the X long enough to reach just inside the corners of the aprons.
Then fasten the top to it, pulling the top flat. The X could flex with wood movement but hold the top flat and then use Samsons buttons to the bottom of the tabletop to connect it to the aprons.
If I had a way to draw a diagram for you I would but hopefully you get the idea. The X could be made from angle iron if necessary I suppose.
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 12/14/2007 9:15 am ET by KiddervilleAcres
KiddervilleAcres - Interesting. But let me explain. The installed table top will have the concave surface pointing up. So there is little need of pinning the surface in the center/middle, only near the long ends.
Of the 8 boards (and they are beautiful), 2 are pretty flat, but 6 aren't. 4 of the 6 have the 1.5" bow and of them 2 are pretty stiff to get them flat, though still I can do it with my hands. The other 2 (of the 4) are not so stiff and the last 2 of the 6 have about 1" bow and also easier to flatten. Sadly, the good sides are all the concave ones, except maybe the smallest and easiest bow. By good side i mean no knots, etc... can't really invert them even if I wanted to.
As I work through this in my head, I think that if I glue up the top without any angle irons on the boards, the entire top will be bowed since nothing will be resisting it. So then when I try to attach the top to the apron, it will be difficult since now I have 6 boards of bow trying to pop up, and maybe that will render the buttons uselss because the friction caused by the upward pressure. A couple of angle irons would relieve alot of the pressure.
I would need pretty good screws to told this stuff down. They will go in about 3/4 - 1in. fine thread or coarse? I am still pretty fixated with using the angle irons, but am leaning away from using the kerfs. Thanks for the suggestions, keep em coming!
As far as the extra stretchers in the middle, I put them in because I was unclear whether you would be trying to pull the middle down (concave side facing down) or trying to pull the ends down (concave side up). As you've now clarified it would be the ends, you could ignore extra stretchers in the middle, the primary purpose of which was to pull down a bowed up middle. I'd still add some extras a couple feet in from both ends, however.
Read Samsons post and his drawing, he drew exactly what I had in mind.
mike
Mike4244 - you don't think that the bowing pressue will create too much friction in the buttons and prevent wood movement in the width direction? of course too much pressure will prevent it, its a question of how much. -yurij
It would take quite a lot of force to prevent width-wise expansion and contraction of the top. If in doubt, you can always wax the buttons and their slots.
-Steve
No, as long as you can easily push the boards flat. If you had to stand on the boards to flatten them then the buttons would not work.
mike
I'd suggest you abandon the biscuit idea. take 2 boards which resulted from a resaw and put them side by side - one bow up, the other bow down. A straight board won't hold a bowed board straight. The result will be in the middle somewhere. So lay the boards out on a pair of lifts that are shimmed parallel, edge-glue and use cauls to hold the whole lot flat while clamping. Don't tighten the caul clamps too much or the boards won't pull together very well. And don't overtighten the edge glue clamps or you'll squeeze out too much glue.
Terry,
You caul lads - but they are so cumbersome!
Still, they are a valid technique, even if biscuits are so much faster, easier.
However, I do cast aleery eye at your advice: "And don't overtighten the edge glue clamps or you'll squeeze out too much glue".
There is a lot of evidence that high clamping forces are required to get glue to work as intended. Any glue squeezed out is excess and will not affect the joint strength. Or do you know different? :-)
Lataxe
Yurij: I can't say that I've actually done this, but what if you re-sawed each 5/4 board again, turned the concave faces toward each other, planed them and glued them together. Would the forces balance each other and yield a flat board? You would lose a little thickness, but not as much as you would if you tried to plane the boards flat. Has anyone ever tried this?
Bob
Bob - As Yogi Bera said, "in theory there is no difference between theory and practice, but in practice there is". I will not try this. I could've just bought 4/4 stock and created 6/4 thick boards, but I would see the glue line on the edges, hence a no go. Reasonable idea though. -Yurij
could you screw the boards to a peice of flat stock and cut slots for a spline ?
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