Large boards for a bench top?

[Sean Girard]

Hey guys...

Fairly new to woodworking and have been thinking about making a bench to replace the sawhorses and old door I have in my shop now. Figured it would be a good opportunity to learn a basic glue panel.

But last night I brought home a few roughsawn boards that are about 12 feet long, 14-1/4" wide, and 1-7/8" thick. I think they are pine. Maybe 100 years old or so. I was told they were used as trusses but don't know for sure. They have been outside for at least the last year. At least one is slightly cupped.

Anyway I was thinking maybe I could just join two lengths together (7 feet or so) and wind up with a good size piece for a bench top. I am wondering if you guys think that is a good idea (vs. gluing many smaller boards) and if so, what method of joinery?

I know that glue is strong stuff but these things are pretty dense and heavy... it seems like there would be a lot of tork on that joint. Should I use dowels or a spline or some other method to provide additional stability?

One of the boards has had a chunk cut out and is only about 5 or 6 inches wide for 7 or 8 of the 12 feet.... I thought about using this piece in between two 14"-wide boards and passing some dowels all the way through the center piece, connecting to each inside edge of the wider boards.

Thanks for any thoughts you all have.

-sean

[Dave MacArthur]

Sean,
I apologize if this is all a review for you, but your questions made me think that maybe you aren't thinking about wood movement and why bench glue-ups are always done quarter sawn.
One of the most critical requirements for a good bench is that it is flat. This is why torsion box benches (like your door) are good assembly tables. If you're working on assembly on a warped bench, you'll have problems.

Flat sawn boards edge joined don't stay flat. Therefore, benches are not usually built that way--because it turns out to be a waste of time and wood. There's a reason bench tops and counter tops all look the same, and it's not just looks.

Remember that as wood changes moisture, the rings expand and contract. If you slice a board tangent to the rings, flat-sawn, then it will expand and contract across it's width the most. Boards almost don't change length along the grain at all. And if you saw a board where it's "width" goes from the bark in towards the middle pith of the tree (quartersawn), it will expand and contract across it's width the least. The THICKNESS of a QS board is the part that is tangent to the growth rings, so the thickness will change.

Now, if you have flatsawn boards (which 14" wide pine is likely to be), and you look at the ends, you'll see that there are rings included, it's a slice of across the surface of a log. As the board changes moisture, it will "cup" and un-cup, and they way it does it is this: The "curve" of the rings will flatten out. So if you start with a flat board, with the rings facing up like "U", those rings flattening out will make the actual board center raise up and the edges turn down.

If you edge join flat sawn boards, you should alternate the rings, up..down...up...down so as the whole thing flexes, it will on AVERAGE stay a wrinkled flat.
But that's not really what you want right? Therefore, the way to keep the top surface from cupping/flexing, is to cut boards into 2" strips, turn the strips on their side... and viola, you have them in a quarter sawn configuration now! You glue a bunch together, all the end grains should look like this: ||||||||. You alternate any grain curve like this: ()()()()
NOW when the wood moves, the top and bottom surface will remain flat, and the only movement will be that the thickness of the top increases and decreases.

If you could get a giant 2" thick slab of hardwood from a tree with 27" radius, that was cut from the bark to the center of tree (quarter sawn) then it would make a perfect bench top. Since it's expensive as hell and not readily available since 1900, we instead just buy a bunch of cheaper flatsawn lumber, cut it in strips and fabricate that giant QS slab.

When you do your glue ups, its all long-grain to long-grain, and will be massively strong without any other reinforcement or splines. The only function of biscuits, splines, etc. would be to keep it all aligned as you glued up a bunch of strips. Not otherwise needed. Many folks just glue on 2 boards at a time and build up their slab over a week or so. Or you could assemble on a flat surface... oh wait ;) ... OK, the door would work with some paper on it, then use a router sled to flatten it. Or a planer, build two and join.

Here's a great link of more reading on the subject that I've found useful:
Basic Wood Anatomy and Behavior (http://www.organicjewelry.com/woodanatomy.html)

Hope that helps!

[Mark Woodmark]

I had a work bench and an outfeed table for years that both were made out of fire rated solid core doors. Hard as a rock, heavy, flat and straight. Cutting them to size was hard though as the inner material dulled my saw blades quickly. They made good bench tops though

[Sean Girard]

Dave - thanks for the very thorough exposition. I had considered wood movement somewhat but I guess I was hoping these were big enough that it wouldn't be so much of a problem. However the more I think about it the dumber that sounds. You have convinced me to put these boards to another use. Maybe I can use them in the base or something.

Mark - You're right that a door is a pretty nice surface. Mine is more of a semi-solid core though and I keep thinking it's time for an upgrade :)

[Steve Friedman]

Dave,

I just want to comment on the explanation of wood movement. It's one of the best things I have ever read on the Creek.

[Gene Waara]

Dave,

I just want to comment on the explanation of wood movement. It's one of the best things I have ever read on the Creek.

I totally agree. Thanks for taking the time, Dave. Some of this I knew but never totally understood.

[Chip Lindley]

Hi Sean! Slab doors make a very good "quick n dirty" workbench for assembling projects and glue-ups. The flatter the better for keeping assemblies square. I have a couple of hollow-core doors that are nice for making off-hand workbench tops when needed.

If you choose to make a slab top of the rough-sawn pine you brought home, rip it into 3" widths, joint it straight, and plane it flat. Glue up your strips alternating the end-grain of each board (smile,frown,smile,frown) into a width (12"?) that will fit through your planer. Careful assembly will leave a slab with little deviation on top, but some clean-up is inevitable. Remove as much glue as possible before planing by scraping or using a chisel. Dried yellow glue will chip planer knives! If your planks are fairly flat to start with, you should be able to end up with almost 1-3/4" thick slabs. Finally, the 12"ish slabs can be jointed together to make the top to final width.

Splines or biscuits can aid in aligning the pieces. Being new at this, take time to "dry fit" the pieces together before applying glue, to see if there are any problems that the clamps will not take care of. You will need clamps spaced about every 12" for maximum control during the glue-up.

This exercise will be your "rite of passage" into the world of gluing up. Enjoy the journey.

~Chip~

[ian maybury]

I'm headed into the same zone shortly after Christmas, and having a Domino am thinking of the possibility of using it to place small floating tenons to align the sections in my bench top when gluing them up.

The wood is European beech, the top will be made up of 1 3/4 x 4 or a little larger boards set on edge and laminated using Bessey parallel clamps.

My personal phobia is that the boards will start sliding around when the clamps start to really put the squeeze on - and that I'll run out of wet time while trying to get it all under control.

I've for this reason been thinking of using a slow epoxy adhesive for the glue up.

An alternative to using dominos may be to use a few pairs of moderately curved cauls placed crosswise and separated from the bench top and the wet glue with polythene sheet.

Maybe I'm being overly cautious with all of this though, as most seem to manage without any help on the alignment - so anybody with experience please come in for my benefit as well as Sean's.....

Thanks

[Dave MacArthur]

Thanks for the nice comments ;) Wish I had some drawings to post in there, always easier to follow for grain talk.

I wanted to mention that, in all honesty, there are some fantastically hardy and great looking "dinner tables" made with flat-sawn wide planks, and a glance at them would actually make you say, "THAT thing would work great as a bench!". Additionally, I have seen pictures of old Roubo-style benches, and drawings from "The WorkBench Book" by Scott Landis that showed workers with probably flat sawn slab benches. So truthfully, it would work OK. BUT, it's not as good a way and there would indeed be some curving movement.

Also--DON'T waste those boards on a bench! Wide, thick, 100 year old pine is a rare and valuable thing! The trees grew stronger for various reasons, I read, and you just don't find boards like that now--you've got something there that probably deserves to be shown in a much better way, and I'd try to use that for furniture!

My Great Great Grandfather moved to Michigan in the 1860s, and they cleared land for family farm... back when old growth white pine was to be found in virgin forests 40" across. They lumbered some 2" thick planks, 15-20" long, and 20" wide, sometime before 1920. Some of them quartersawn. It was stored in a long woodshed, and passed on to my Father about 10 years ago. My Dad used those beautiful boards to make single-plank table tops for dressers and desks for the old family cabin, and every time I use one of them I can't help but think of my relatives cutting the trees and caring for the wood for almost a hundred years. And I've never seen any pine that looks remotely like it. So, give some thought to doing something neat with those boards, since you don't need the width to make your bench ;)

[Matt Ellis]

dave,

i want to say thanks too. your post is the first that i have actually copied to a word file for later reference.

-matt

[Steve Friedman]

And I've never seen any pine that looks remotely like it.

Maybe that's because you live in Phoenix! j/k

What about making a split bench top, with each side being two (or 3) pieces of quarter-sawn 8/4 wood (laminated together)? Would that work or is it still better not to use wide pieces like that on a workbench top?

The prospect of gluing up a bench top without a power jointer and planer is daunting. I love my LN #8, but get short of breath just lifting it to the bench. Getting the wood dressed by the lumber mill is a nice idea, if they would come to my house after the wood has been sitting in my garage for a couple of weeks.

Thanks,

Steve

[Erik France]

My personal phobia is that the boards will start sliding around when the clamps start to really put the squeeze on - and that I'll run out of wet time while trying to get it all under control.I built my bench out of ripped SYP 2x12s a couple summers ago. Cauls made alignment really easy, two on each end and two in the middle. I also found that just doing 3 or 4 strips per glue up was better than trying to do too many at once. I did a few dry runs and I couldn't get more than 4 coated and clamped for my glue's open time. I was using Tightbond III. It was pretty warm out, so the open time was shorter. A roller applicator made it quicker getting it on and spread.

Doing the top in smaller sections also let me use some of my shorter clamps too. I was able to do two smaller sections at a time before I ran out of clamps and room in my little shop.

[Brian Tymchak]

I'm headed into the same zone shortly after Christmas, and having a Domino am thinking of the possibility of using it to place small floating tenons to align the sections in my bench top when gluing them up.

The wood is European beech, the top will be made up of 1 3/4 x 4 or a little larger boards set on edge and laminated using Bessey parallel clamps.

My personal phobia is that the boards will start sliding around when the clamps start to really put the squeeze on - and that I'll run out of wet time while trying to get it all under control.

I've for this reason been thinking of using a slow epoxy adhesive for the glue up.

An alternative to using dominos may be to use a few pairs of moderately curved cauls placed crosswise and separated from the bench top and the wet glue with polythene sheet.

Maybe I'm being overly cautious with all of this though, as most seem to manage without any help on the alignment - so anybody with experience please come in for my benefit as well as Sean's.....

Thanks

Ian, Sean,

I'm on the home stretch of my new bench, laying out dogholes. I can tell you my approach to glueing up the top. It may help out. My bench is a pretty faithful reproduction of the 21st Century Workbench - PWW, October, 2008. The top is actually a split top consisting of 2 - 12" x 3.5" x 90" tops. Each top consists of 8 1.5" thick laminations.

First, I used titebond III which has a little longer open time than TB I, II. I first made sure I had 1 good flat face and 1 good square edge on each lamination. Following the PWW articles advice, I first glued up pairs of laminations and then, after jointing/planing fresh faces and 1 square edge on the pairs, glued the pairs up to the full top. Gluing in pairs certainly helps tame some of the panic to meet the open time of the glue. Another tip from the article was to spread glue using a 2-3" trim paint roller, and to spread glue on only 1 face instead of both. The roller worked great. You can spread a lot of glue very quickly that way. In fact, I found that I had enough time to do a rub-joint on the pairs glue up. I also got very little squeeze-out since only 1 face was spread with glue, cutting down on the cleanup. I found a disposable roller kit with tray at the HD for a couple of $$. Very handy. I was also able to cover the tray and roller with plastic wrap and keep leftover glue fresh for several days. When done, just toss it all.

Here's another tip I can offer that greatly helped align the laminations on glue up and cut down on the overall effort. I made up a couple of "jigs" for lack of a better term to help the glue up. I jointed/planed a couple 2x2s about 18" long such that 2 faces are parallel. On each of these, I glued a strip of 18" long half round molding. I set these up on the floor (you could use a bench if you have one) about 60" apart and shimmed them such that they were level according to a bubble level across the top of the round. This put the top edges of the 1/2 round in plane with one another. So now, putting the square edges of the laminations down on these jigs pretty well guaranteed the down side of the laminations to be in alignment. After spreading glue, rubbing the joint, rolling the edges down on the jig, I positioned clamps and then, before tightening them down, used a hammer to tap the laminations firmly down against the jigs. I then tightened the clamps. I also used the jigs to do the final glue up of 4 pairs. Gluing up in pairs first meant I only had to spread glue on 3 faces when putting the pairs together for the final glue up. In retrospect, I'd recommend putting a coat of varnish on those jigs to keep squeezeout from sticking. I used plastic wrap but it was hard to manage on occasion. Don't be tempted to use more than 2 of these jigs. A third could easily and likely be out of plane with the other 2, throwing off the alignment.

Last tip: Since I faced and edge jointed the pairs and then planed the whole top, I did not dimension my laminations to final thickness and width at the beginning. I left them about 1/8"-3/16" long in both dimensions. After the pairs glue up, I face jointed and planed the faces of the pairs to final width (1.5" each or 3" total). Then after the final glue up, I planed the whole top to final thickness (3.5").

So, that was kind of a rambling dissertation on my glue-up process. I hope it helps you out. Let me know if you have any questions or if there is something I didn't spell out clearly.

Good luck with your bench!
Brian

[ian maybury]

I should have thanked yourself and the others in my last post too Dave. Thank you. I hope it doesn't feel like I'm hijacking your thread Sean, please come in and I'll but out if you have more questions....:o

It sounds like the cauls (Erik), a roller to speed glue application, and not getting too ambitious in trying to glue up too many laminations at a time (Brian) are the way to go - the point being that it works out fine with a bit of forethought. Saves the need to go with epoxy too.

I'll be working on a (concrete) floor too when I glue up the top Brian, so the jig strips sound like the plan. If using cauls too they will need to be of a less deep section so they don't touch the floor like you warn against.

It seems like it might be worth running a couple of coach screws (not sure what you guys call them) through to secure the two jig strips to the floor (after leveling) to prevent their being disturbed during clamping, or lifted up by any tendency to twisting when the laminations are clamped up.

It seems too like maybe the laminations could easily end up slightly curved in the horizontal direction, and that if this happened that the different 'bundles' might not go face to face without quite heavy jointing. It could be overkill, but I wonder if maybe clamping each bundle against a length of steel box section or whatever when gluing up might not be a useful move to keep them (mostly) straight in the horizontal?

My bench by the way looks like being an 8ft Schwarz style Roubo, but with a Veritas twin screw vice on the front, and a large Veritas non quick release on the end (to enable pressing stuff apart) - with no tool tray on top.

The plan is for 3/4in round dog holes so I can use some Gramercy hold downs I bought. The big question on these seems to be whether it's advisable or not to drill a full grid of holes lined up with dog holes in both of the moving vice jaws - or whether a single row is enough with these vices...

ian

[Sean Girard]

No problem at all Ian. Lots of great information being shared in this thread (big thanks to everyone) and since I see a glue up in my future I'm happy to let you run with it!

Having said that: If anyone has any clever ideas for things to do with a few big ole pieces of pine I'm all ears. Sure wish those entry level planers came in 14" versions.

-sean

[Erik France]

I'll be working on a (concrete) floor too when I glue up the top Brian, so the jig strips sound like the plan. If using cauls too they will need to be of a less deep section so they don't touch the floor like you warn against.I did my top glue ups on the bench base I built. It sure beat gluing up everything on the floor like I did for the laminations on the 5" & 7" legs. Mine is a Roubo like design as well. I put stringers that would be flush against the top between the front and back legs. I did the top glue ups across those stretchers. The base was level and solid. The only problem was the two tenons on the front legs sticking up that were to go into the future top, but it wasn't that big of a deal.

It made it easy to clamp on alternating sides of the top pieces. I was also able to use some stout 2x8 & 2x12 cauls on the top and bottom when I started putting the pieces together for the whole top.

I wonder if Roubo would be as commonly known today if it weren't for Schwarz. ;)

[Brian Tymchak]

It seems too like maybe the laminations could easily end up slightly curved in the horizontal direction, and that if this happened that the different 'bundles' might not go face to face without quite heavy jointing. It could be overkill, but I wonder if maybe clamping each bundle against a length of steel box section or whatever when gluing up might not be a useful move to keep them (mostly) straight in the horizontal?


No, it's not overkill. In fact, that is what I did. Sorry, I didn't mention that. I built a box beam out of 3/4" plywood 8' long and clamped the pairs to that when glueing them up. I also took some time with a belt sander and level to make absolutely sure that I had a flat face on the beam to clamp to. So, in fact, I made an error in my first reply. I jointed both faces of the laminations to start with to have a flat face on the beam. >I did not use the jigs to glue up the pairs, only when gluing up the final top.< Sorry for that mistake. It's been many months ago I did that part.



The plan is for 3/4in round dog holes so I can use some Gramercy hold downs I bought. The big question on these seems to be whether it's advisable or not to drill a full grid of holes lined up with dog holes in both of the moving vice jaws - or whether a single row is enough with these vices...



I too have a 24" Veritas twin-screw (30" chop) in the face position and a Jorgy 9" quick release (with 12" chops) in the tail. I don't see myself using hold fasts all that much so I did not lay out my dog hole plan to optimize use of hold fasts. I thought more about using some square-headed dogs that I will turn to fit the 3/4" holes.

I'm sure in a room with 10 bench builders, there will be at least 10 ways to lay out dog holes... Here's my plan that I just marked out last night on my top. (Painters tape is a wonderful invention...;)) Instead of using the metal dog on the Jorgy, I will put 2 holes in the 1.5" thick vise chop and run 2 rows of holes in alignment with those at 6" intervals down the top to the other end. With the top being 90", the first set of holes set at 3" from the end, this will align with 5 holes in the vise chop of the face vise.

I will also add another row of holes on the far side of the top, in alignment with the holes on the front side of the top, but drilling just every other one, starting with the hole at 3" from the end. This row of holes will give me over 36" length from the holes in the front vise. This might actually be a bit of overkill as my top is a split top design and I can clamp work down in the middle of the top. In fact I've already used that feature of the table. (I think I will use that feature a lot. Have to admit I put a lot of thought in to it before going ahead with the split top design.)


The only issues I had with this plan were:

The holes at the 15" and 75" marks will fall on the leg structures. So, hold fasts can't be used there. But, given what I said before, I'll live with that. I couldn't come up with any consistent spacing plan that cleared the legs and aligned with either 4 or 5 holes in the face vise. ( I mapped out probably 25 potential plans in Excel trying to figure it out.)
To gain clearance between the leg structure and the screws on the tail vise, I had to use 2 1.5" chops in the tail vise. This gives me I ~5.5 inches travel on that vise. So, with a 6" spacing of holes, there's about a 1/2" gap every 6" of board length beyond 10" that I can't just clamp in between dogs in the vise and top. That kind of offends my sense of perfection.. :rolleyes: But, in the end, I decided to just add a spacer board against the dogs to handle those special occasions.
This bench design has the top, rails, and legs in alignment on the front of the bench. I have not yet laid out the holes in the front faces (in the side of the top, the upper and lower rails) but I'm pretty sure those will be on 6" centers as well, though offset from those on the top. I will run 1 or 2 holes into the legs as well. This plan is pretty much the same that the the PWW article laid out.

Sorry for the long-winded reply. I just get to typing and .. well.. it's completely out my control at that point...

Brian

[Matthew Hills]

Didn't Chris Schwarz do a bench top out of two large timbers recently?

Think it was the one shown on the cover of his book, too:
http://images.fwbookstore.com/large/Y0655.jpg

Matt

[Rick Pettit]

Plastic resin glue is the answer for any complicated glue up. It costs less than epoxy and works better. Epoxy doesn't want alot of clamping pressure forcing the extra glue out. You can treat plastic resin glue the same as any yellow glue. The stuff has an open time of three hours plus. It's strong too.

[ian maybury]

:) I'm no slouch Brian when it comes to long posts myself, and these benches are damned addictive.....

I just think the Roubo is such a beautifully pared down design, with what's needed where it's needed Erik. I'm a definite Schwarz fan too - he's very practical.

That's very similar to what I'm thinking of by way of a dog hole grid Brian. The plan is to draw it up fully to sort out the details.

Sounds like building the base first so that it can be used as a work support might make some sense Erik - which actually raises another point. Chris Schwarz used the more traditional direct insertion of the legs into the top - with no high level support rails/stretchers under the top.

The issue he mentions that this creates is that movement in the width of the top spreads/closes the legs. Which seems to be structurally OK - but it knocks the vertical face defined by the legs/occupied by the dead man out of square with the top.

I've been toying with fixes for this. There seems to none that covers all the bases, but one option would involve tightly tenoning the tops of the working/near side/face legs into the top. Ditto for the rearwards pair of legs, but I thought of fitting strong rails/stretchers between the legs (across the narrow dimension, but down a little), and making the rear pair of leg mortices oversize in one dimension so that the tenons can slide in them.

i.e. the near side edge of the top (being fixed by the leg mortice/tenon fit) would stay flush with the vertical face defined by the near side legs, but the back edge would move in and out a little relative to that pair of leg with movement of the top - enabled by the oversize two back mortices.

I thought then that I could use four of the heavy forged steel gudgeon pins we use over here to hinge fold down trailer tail gates and sides in a manner a little like we use cleats and slots to enable movement while holding down a table top - http://www.trailertek.com/acatalog/Tailgate_fittings_and_fastners.html (see item BF203 about half down the page)

I this case the gudgeon pin flanges would be screwed to the top with heavy coach screws, and would enable movement and simultaneously hold down the top by having the circular section part enter holes drilled in the inner vertical faces of each leg. This would also enable removal of the top for transport if required in future too.

Does this sound feasible to you guys?

Ian

PS Rick - can you name an example of the plastic resin you are thinking of?

[Erik France]

I ended up just mortising the two front legs into my top. The front edge of the top will always be flush and square with the legs. I planned on pining the top down with some dowels through the face and into the tenons. I haven't needed to do it. Gravity keeps the top in place very well, and the mortises were pretty tight too.

I did have tenons on all 4 legs, but I cut the back two off as I feared the top might get pulled apart as the top dried. The SYP I was using was still a little wet. My little shop isn't insulated either, and I only heat or cool it during extreme temperatures when I'm in it. The humidity out there really swings. I figured the top would split over time.

My bench design is a little different than most I have seen. My shop is tiny (10x12) and during the long process of designing my bench I ended up leaving the front open so my flip-top planer cart can roll under. I did two stretchers front to back per leg pairs and a 2x12 stretcher on the back two legs. I oversized it to help with racking, and to add a little more mass. My left legs are ~5x5 and the right ones are ~5x7. I did those a little wider for my leg vice, and to bump up the weight. Once I got the top onto the tenoned front legs the thing was rock solid.

[ian maybury]

Thanks Erik, that answers my concerns nicely. Sounds like you're not missing having a flush back face, and that holding the top down is not that big a deal.

Sounds too like the need to go with the double short stretchers you need (unless the plan was to use a leg mounted wooden vice the screw of which needed that space) isn't a problem either.

ian

[Brian Tymchak]

:) I'm no slouch Brian when it comes to long posts myself, and these benches are damned addictive.....


So true.. I've only built this one, and I only need this one (I think..;)), but I've already thought of a couple things and methods I would do differently if I were to build another...



Sounds like building the base first so that it can be used as a work support might make some sense Erik

Agreed. I mulled over building the base first or 2nd and couldn't come to a conclusion. So, to get moving I followed the article and did the tops, parked those on saw horses and built the legs using the tops. My thinking was that I needed the flat tops to assemble the legs square (although I still managed to rack one a tiny bit in the glue up... :mad:) Erik's idea about using the legs to glue up the tops did not occur to me and probably would have changed my plan.

[Erik France]

I'm not overly concerned with the back face being absolutely flush with the back leg faces. With my little shop it hardly ever gets moved away from the wall. The top was made as deep as my base initially. I haven't looked at the back in quite a while, so I'm not sure how far it's off now, if at all.

I was skeptical at first about just gravity holding the top down, especially before I even started the build. There were a few discussions about bench tops I followed on another forum that led me to go with just the tenons. Once I glued up the 30x73 SYP top and put it on the base I found it wasn't going anywhere. That was before I added the weight of the two cast iron Wiltons. It's pretty heavy, it takes quite a bit of effort just to lift it just a fraction of an inch at the back. The photo below showing the mortises has some dark marks from the dead blow hammer I had to use to get the top back off from the initial dry fit. I believe the tight fit of them helps with the rigidity of the bench.

I did the final base assembly on top of my knockdown outfeed table for my saw; a rib reinforced hollow core door. Most all of the joinery construction was done with half lap joints. The mortises in the top were cut in one of the top strips with a dado stack before I did the final glue up. Same thing for the leave out for the face vice.

Flipping the top by myself wasn't the safest thing to do. I never really had to pick the whole top up outright though. The final top glue up was already on the base so part of it was always supported by the base. I didn't think of it during the build, but I'm glad I didn't have to transfer the whole top from the floor or elsewhere to the base.

[ian maybury]

Thanks for the photos Erik, very informative. Hopefully they will help Sean too. That's a very nifty looking bench - the large section legs make it.

All I have to do now is to finish my workshop refurbishment, draw up and build it...

ian

[Rick Pettit]

Ian, the plastic resin glue I use is made by DAP.

[Terry Beadle]

The issue of glue up with large pieces is some times helped by dropping a few grains of sand in a few spots while the glue is being spread out. Not much sand but the little grains here and there create a small micro peg between the two glue surfaces and help keep them from wiggling around.

You don't want enough sand to make the joint stand off but enough very litely applied in a few spots.

Sort of like the sand used in some of the products you can apply to stairs and garage floors to keep from slipping while walking on it.

[ian maybury]

Ha! That sounds like the plan Terry, although you might want to be careful planing afterwards....

[Eric Viglotti]

Hello,

I am working on an engraved serving tray idea and to do this, it looks best if the wood used is one solid, wide boards rather than a glue-up of smaller boards. I've done a few of these and have used 4/4 maple one time and cherry another time. The boards I have been using have been 9 to 10" wide and about 18" long all in one piece. Since they are wider boards, they are definitely flat sawn. I end up coating them with 2 coats of urethane on the front, back and all sides. One of them has been completed for about a month and doesn't seem to have cupped or warped, but what are the chances I can still get away with this concept? The wood has all been properly dried and is from a reputable hardwood dealer. Am I still doomed to using a board this wide for this function or do you think I might be able to get away with it? Granted it doesn't need to stay absolutely perfectly flat forever, but as a serving tray, the person using it ideally shouldn't notice anything warping, rounding or cupping.

And Dave, great post on this topic, super informative which is what led me to quote it here :)

Thanks!


Sean,
I apologize if this is all a review for you, but your questions made me think that maybe you aren't thinking about wood movement and why bench glue-ups are always done quarter sawn.
One of the most critical requirements for a good bench is that it is flat. This is why torsion box benches (like your door) are good assembly tables. If you're working on assembly on a warped bench, you'll have problems.

Flat sawn boards edge joined don't stay flat. Therefore, benches are not usually built that way--because it turns out to be a waste of time and wood. There's a reason bench tops and counter tops all look the same, and it's not just looks.

Remember that as wood changes moisture, the rings expand and contract. If you slice a board tangent to the rings, flat-sawn, then it will expand and contract across it's width the most. Boards almost don't change length along the grain at all. And if you saw a board where it's "width" goes from the bark in towards the middle pith of the tree (quartersawn), it will expand and contract across it's width the least. The THICKNESS of a QS board is the part that is tangent to the growth rings, so the thickness will change.

Now, if you have flatsawn boards (which 14" wide pine is likely to be), and you look at the ends, you'll see that there are rings included, it's a slice of across the surface of a log. As the board changes moisture, it will "cup" and un-cup, and they way it does it is this: The "curve" of the rings will flatten out. So if you start with a flat board, with the rings facing up like "U", those rings flattening out will make the actual board center raise up and the edges turn down.

If you edge join flat sawn boards, you should alternate the rings, up..down...up...down so as the whole thing flexes, it will on AVERAGE stay a wrinkled flat.
But that's not really what you want right? Therefore, the way to keep the top surface from cupping/flexing, is to cut boards into 2" strips, turn the strips on their side... and viola, you have them in a quarter sawn configuration now! You glue a bunch together, all the end grains should look like this: ||||||||. You alternate any grain curve like this: ()()()()
NOW when the wood moves, the top and bottom surface will remain flat, and the only movement will be that the thickness of the top increases and decreases.

If you could get a giant 2" thick slab of hardwood from a tree with 27" radius, that was cut from the bark to the center of tree (quarter sawn) then it would make a perfect bench top. Since it's expensive as hell and not readily available since 1900, we instead just buy a bunch of cheaper flatsawn lumber, cut it in strips and fabricate that giant QS slab.

When you do your glue ups, its all long-grain to long-grain, and will be massively strong without any other reinforcement or splines. The only function of biscuits, splines, etc. would be to keep it all aligned as you glued up a bunch of strips. Not otherwise needed. Many folks just glue on 2 boards at a time and build up their slab over a week or so. Or you could assemble on a flat surface... oh wait ;) ... OK, the door would work with some paper on it, then use a router sled to flatten it. Or a planer, build two and join.

Here's a great link of more reading on the subject that I've found useful:
Basic Wood Anatomy and Behavior (http://www.organicjewelry.com/woodanatomy.html)

Hope that helps!

[David Buchhauser]

Hi Eric,
It's probably best to start an new thread with your questions, although I'll bet some of the "eagle eyed" members will still respond.
David

[John K Jordan]

Eric, would you like your post to be moved to a new thread?

It would still keep the quote you included but your message might be a lot easier to find if not buried deep in the 2010 thread. We could include a link to the old thread if that might be useful to readers.

JKJ

[Eric Viglotti]

Will post a new thread now. Thanks for the tip!


Hi Eric,
It's probably best to start an new thread with your questions, although I'll bet some of the "eagle eyed" members will still respond.
David

[Rod Sheridan]

When I lived in BC, we had a bench that was a 6” thick slab of quarter sawn Douglass Fir 38” wide and 12 feet long..

The bench was 2 of slabs across when my parents bought the house however Dad cut the bench in half because it was too wide.

You don’t see timber like that any more....Rod