Oh hey, wood moves! (Aka, don't glue things cross grain)

[Luke Dupont]

Hey guys.

So, my awesome new sloyd bench, which I planed dead flat 3 months ago, is now cupping with a concave on the top.

But, I realized the reason why, and just planing it flat isn't the solution.

If you look at the design of sloyd benches like I built, you'll see that on the underside, there is a "width wise stretcher" attached to the underside of the bench where the leg assemblies go, to raise the leg assemblies above the vice hardware. Well, I glued those on cross-grain, like an idiot. You can imagine what happens as winter comes and the humidity drops off drastically: the width wise stretchers don't shrink, staying the same length, but the width of the bench (long grain) shrinks. Because the top of the bench is able to shrink in width, and the bottom is not (glued to the long grain stretchers) the entire bench top, over 2" thick, cups! And in so doing, it even bends those stretchers along with it, meaning they've become slighly convex on the underside, which is not great for width-wise stability, allowing some potential see-saw like rack to take place.

If I want to correct this, I need to remove my vise hardware and rip those stretchers off and replace them. Yikes.

This doesn't just happen with this bench though. I inspected a quick and dirty benchhook I made, which I also glued cross grain. Same thing, cupping! And each end cups a different direction, because the stops are on opposite faces.

Wood shrinks in one direction and not the other. Plan on it. We all know this, of course, and I think all of you more experienced guys don't need to hear this, but I've been doing this on and off for years now and still made these huge, and very rookie mistakes. So, to all my fellow rookies, take this seriously! You can't just overcome the power of wood with glue and fasteners and expect to tame it. It'll move however it wants to, so you had better count for that and work with that tendency rather than against it.

[Richard Coers]

Woodworking 101, but often ignored by the generation that learns from TV and Youtube.

[Russell Nugent]

Yeah I'm sure older woodworkers never made the same mistakes because they just always knew better.🙄

[mike stenson]

Yea, over all a pretty crass comment. If we start to see younger people stop being interested in hand tool woodworking (fortunately, it doesn't seem we are), I know why.

[Robert Engel]

Well…..you can get away with some things, but slabs are a totally different story.

One of the first projects I ever made 30 years ago was a coffee table - simple design with aprons. I mounted the top using dowels all over. The darn thing never moved until my son got it and put it on his patio - the. It split in 2 places. Go figure humidor outside is much higher.

I’ve seen plenty of antique furniture built with drawer runners glued to a side panel that are not cracked and always wonder why?

[Jason Buresh]

Woodworking 101, but often ignored by the generation that learns from TV and Youtube.

What's the issue with TV or YouTube? I have learned a lot from Roy Underhill. There are also good videos on YouTube, and there are also bad. I read lots of books, but sometimes watching how something is done is an easier reference than reading how something is done.

I am about to turn 30 this year, and I am the only one of my friends and family that works with hand tools, let alone woodworking. YouTube, tv, books, and this forum have taught me a lot. Especially in today's world, when taking an in person class is a hard thing to do. I didn't grow up in a time when I had the benefit of learning from someone who had no choice to use hand tools and not a table saw and CNC machine.

I appreciate that he shared his mistake, because we all make mistakes. Today on Instagram and Facebook people don't share real life experiences, they only show perfection to see how many likes they can get.

A wise man learns from his mistakes, but the wiser man learns from others mistakes.

[Rafael Herrera]

Robert, I could guess a few possibilities. The ones that crack get thrown away. The panels that survive may have been quarter sawn pieces.

Many of the howtos found in the internet or YouTube pay little attention to taking wood movement into account in a design. The focus is on giant glue up assemblies or high precision flattening w some fancy tool.

[Rafael Herrera]

Luke, did the plans for your bench call for the stretchers to be glued?

Wood does move length-wise. Check out the wood database for the different rates according to species.

[Edward Weber]

Everything needs to be done in proper proportion to avoid the issues the OP experienced.
Adding supports perpendicular to the grain on the underside of tables and benches is common. The problem comes when they are too small, there's not enough of them or both.
A 2" thick top can require a lot of reinforcement if it's going to be restrained from cupping, depending on all the variables like grain orientation, relative humidity etc.

[Andrew Seemann]

I have an Armoire that I made 25 years ago that I think I made every possible wood movement mistake on. It happens to all of us at some point, usually earlier than later:)

[Luke Dupont]

Luke, did the plans for your bench call for the stretchers to be glued?

Wood does move length-wise. Check out the wood database for the different rates according to species.


See, that's the problem. I didn't have plans.

I was going for a Sloyd bench, which is not a popular bench to build, and for which there aren't any plans available to my knowledge.

Even when I want to find plans on a bench, I find it extremely hard to find plans that are 1) meant for Neanderthals, and 2) actually what I want to build. The more I study old furniture or workbenches in construction and think about how to approach my own projects, the more I appreciate just how much thought goes into the traditional designs. Unfortunately, I'm always left with unanswerable questions because I never have the real pieces to inspect, only pictures to go by.

"Filling in the missing pieces" as a novice, even an experienced novice, often results in more than a few mistakes.

How do you guys do this? Where do you even find plans meant for Neanderthals, let alone any plans for the specific thing you want to build? I was scouring the internet looking for "Scandinavian / German / Dutch / Swedish" workbenches and couldn't even find plans for traditional, all joinery construction not using modern methods -- much less anything on Sloyd benches or turn of the century "Cabinet Maker's Benches" like these, which are what I'm interested in:

https://cdn.discordapp.com/attachments/604955857889001487/914770640911892501/Fig-8-Single-Bench-Vao-Top-5-feet-long-by-1-feet-broad.png
I'd love to know the construction of the underside of this cabinet maker's bench, and how the thin board is supported or joined to the rest of the piece, as well as how that tool well and "apron" going around the sides and back are joined and constructed. I can only guess and make stuff up.

Or this:

https://bushcraftusa.com/forum/attachments/sloyd-workbench-png.1392145/
EDIT: The above picture isn't appearing for some people, so here it is again:
472472

You can see the offending stretchers on the Sloyd bench, where the mallet and spokeshave are hanging. Guess I should have cut some sort of sliding dovetail and not glued it? Or just used a bracket or nails or something?

[Tom Trees]

If I got things right, what you're saying are strechers, are infact end caps?, regarding a Scandi bench.

You might have some luck by searching for Frank Klausz workbench, many plans on google
Here for example
https://vdocuments.net/frank-klaus-workbench.html
Rob Cosman has two benches should you want to see,
https://youtu.be/DqhYuMq8_ko
and
https://youtu.be/U-3c5UNgDBo

[James Pallas]

Luke, I have had these books in my library for many years. I know they were reprinted in the 1970s. I didn’t check but you may find them for sale on the net or may be available at your local library. They are for the most part hand tool reference books. I still get them out on occasion to help my memory. I may have done something a long time ago and have just forgotten, that’s an age related thing I’m told. I think they may be just what you are looking for.
Jim

[Luke Dupont]

If I got things right, what you're saying are strechers, are infact end caps?, regarding a Scandi bench.

You might have some luck by searching for Frank Klausz workbench, many plans on google
Here for example
https://vdocuments.net/frank-klaus-workbench.html
Rob Cosman has two benches should you want to see,
https://youtu.be/DqhYuMq8_ko
and
https://youtu.be/U-3c5UNgDBo

Thanks! I will check out the links.

Well, in regards to the first picture, the turn of the century cabinet maker's bench, yes, the end caps and also what's underneath the bench and how the thick part at the edge attaches to the thick edge (where the dogs are) on one side and the tool well on the other (is there a vertical piece separating them? and how is that attached if at all to both the thin top and the end caps?) are unclear to me.

But the bench I built is the second one, and the problem piece that I describe is not an end cap but rather the "raiser" for each leg assembly, again, if you look where the mallet is hanging.

I will be using this bench as is for quite some time and probably need to do some surgery on it, but at some point I may opt to make a simplified scandinavian bench, of the type in the first picture I posted, without the complicated end vise (which is not a good use of space on a short bench anyway, and is more versatile, I feel).

[Edward Weber]

I only see one diagram in the post, I don't know what you're trying to compare.

[Jack Dover]

Would you mind making a photo of table of contents for both of them? I was assuming they're just different editions.

What's interesting about these books is they're a compilation of articles published in the "Work" magazine (and some other magazines) at various times. Bernard E. Jones was one of the editors of said magazines, together with Paul Hasluck, whose writings are immensely popular too.

[Luke Dupont]

Updated the original post:
472474
Hopefully that appears. The "leg raiser" which the mallet, brush, and spokeshave are hanging off of (raising up either leg assembly above the vise hardware) is what I crossglued and am trying to figure out how I should have joined instead. There's also the "end caps" (except they're attached to the underside of the bench rather than the endgrain) which I should consider what to do with.

[Tony Wilkins]

I think I would have connected it with a screw with room provided for movement or nail it from the underside. The other option would be to use a sliding dovetail with glue in middle or front end only.

[Rafael Herrera]

I've read or seen this method before. If the top is heavy enough, it can be attached with pegs. The front pegs a snug fit, the rear pegs fitted into mortises to allow for expansion.

I found the video...

https://youtu.be/2Qa_1xICXTE

The cross board you glued to the bottom of the bench top, they should have been glued/attached to the legs instead.

[Luke Dupont]

I've read or seen this method before. If the top is heavy enough, it can be attached with pegs. The front pegs a snug fit, the rear pegs fitted into mortises to allow for expansion.

I found the video...

https://youtu.be/2Qa_1xICXTE

The cross board you glued to the bottom of the bench top, they should have been glued/attached to the legs instead.

Ah, interesting. I am actually using pegs, but it's pegged into the board I glued, and not the top of the bench. Maybe you're right and I should have attached the board to the leg assembly and not the benchtop... but I'm also using it to act as an extra guide for the vise guide bars, to reduce the excessive rack the vise had. I could accomplish the same thing with separate blocks attached to the underside though, of course.

[Scott Winners]

Luke, you are running up against what I see as the biggest bugaboo in workbench construction; and your thread is timely as I had just glued a thing crossgrain about two days before you started your thread.

Coming at it from the English perspective as espoused by Paul Sellers, the items you have labeled "leg raisers" would be called "bearers" in Paul Sellers World. Those pieces 'bear' the weight of the top and transfer that weight to the undercarriage.

As you have discovered, full length glue (which I also did on my screw up) is not a lasting secure square joint.

Once you have it apart, you could do screws or lagbolts, as has already been suggested. You can fasten it down tight at the front, and then use elongated holes towards the rear of the bench so seasonal movement is not at the front of the bench.

You could glue it down just at the front, and in an apartment setting that might work OK, but if you are ever free to make noise chopping mortises with a chisel and mallet that may not be secure enough.

In your situation I think wood pegs snug at the front and another pair of wood pegs in elongated holes at the back might be the way to go.

If you can find them, nails could maybe bend back and forth with the seasons.

The advantage to pegs is they aren't going to chew up the benchtop with seasonal wood movement. I went with through mortise and tenons here, I can see the end grain of all four legs on my bench top. My legs are shouldered with no 'bearers'
or 'leg raisers' to be found - but I am in an area with extreme humidity swings, and wanted to avoid metal fasteners between bench top and undercarriage.

If I only I had remembered I was in an area with extreme humidity swings when I glued up crossgrain right before your reminder.... Thanks, seriously thank you for the reminder. I am going to have to bust about my clothes iron and go soften some hide glue.

Best wishes.

[Jack Dover]

how I should have joined instead.

Lag screws in slotted holes would be the easiest I think. A while ago I had do a similar job, and while I could drill trough the bearers, I didn't have lag screws long enough. So instead a length of angle iron was screwed to bearers' sides about 1/4" below the top edge. Slotted holes were drilled in the iron, then lag screws went through them. 1/4" is arbitrary, but don't mount it flush, because this gap it allows straightening a table top somewhat by just tightening screws.

If you feel fancy - sliding dovetails are the way to go.

Btw, I think the end caps on such a thick top aren't for keeping it straight, it's rather to inhibit moisture exchange, so having them anywhere except nailed to end grain kinda defeats the purpose.

Are you planning on ripping the glued crosspieces off? If the glue was PVA - acetone will soften it, might save you some work. Heat softens it too, but not sure whether it's possible to heat thick pieces.

[Richard Coers]

Yeah I'm sure older woodworkers never made the same mistakes because they just always knew better.
NO, we were taught by a good Industrial Arts teacher. People building log cabins learned the hard way when the wind could blow through the cracks in the winter and the doors wouldn't close in the summer. This information is centuries old.

[Richard Coers]

Yea, over all a pretty crass comment. If we start to see younger people stop being interested in hand tool woodworking (fortunately, it doesn't seem we are), I know why.
You ever look at reddit woodworking? At least half the beginning woodworkers show cross grain construction and are asking how to fix the cracking. The most common fix is fill it with resin, not that the construction was incorrect in the first place. Some guy just posted a barn door he made for a commission that was built incorrectly and the thing had a 1" gap from the bow. All I am saying is that poor instruction leads to poor craftsmanship. And they get that poor instruction from someone more concerned about youtube subscription numbers than teaching basic woodworking. I'm damned proud of my 50 years of woodworking (24 years professionally) experience and thought I can help teach others. As I said on the other reply, wood movement has been known for centuries!

[Rafael Herrera]

Woodworking 101, but often ignored by the generation that learns from TV and Youtube.

That's like saying everybody knows you shouldn't do that, it's a useless comment. It's done, the guy is asking for help on how to fix it. Since you have that much experience, why don't just tell him how to fix it.

[Jack Dover]

Woodworking 101, but often ignored by the generation that learns from TV and Youtube.

Ahahah, with all the come backs at you I just really hope your fox hole is warm, dry and comfortable!

Just for balance sake's I know a number of people who learned from YT and who are at least an order of magnitude better woodworkers than me, who learned from professionals live. It's just some people are more talented or maybe better students than others.

But I do get your sentiment, tons of examples that are beyond hilarity and I wrote about this extensively at that other forum.

[Edward Weber]

Woodworking 101, but often ignored by the generation that learns from TV and Youtube.


Lots of fuss about this comment but I don't see anyone saying you're wrong.
I didn't think your comment was aimed at the OP to be harsh or mean spirited, just a statement of how you see things these days. and I agree with you about YouTube.

We all make mistakes and hopefully learn from them. A little practical experience goes a long way. Relying on the short attention span format of most presenters on YouTube is not going to provide you with an in depth knowledge of woodworking in most cases. The term "101" means, introduction to, or things you learn early on, things you should know.
Do YT presenters often skip over the basics, yes they do. IMO

Hopefully the OP received enough info to resolve his issue. Personally I would use dovetail keys or battens to keep the top flat but that's just a difference in design.

[Rafael Herrera]

Lots of fuss about this comment but I don't see anyone saying you're wrong.
...
...use dovetail keys or battens to keep the top flat but that's just a difference in design.

It's not a helpful answer, not that I'm advocating we be all PC to everybody all the time, but if you're taking the time to answer, throw something useful as well.

I'm not an authority on wood movement, far from that, but thick boards like those used on a bench won't be held flat with a batten, unless it's also big and you bolt the crap out of the assembly. I could be wrong, others could chime in and say I'm full of sh***.

[Richard Coers]

It's not a helpful answer, not that I'm advocating we be all PC to everybody all the time, but if you're taking the time to answer, throw something useful as well.

I'm not an authority on wood movement, far from that, but thick boards like those used on a bench won't be held flat with a batten, unless it's also big and you bolt the crap out of the assembly. I could be wrong, others could chime in and say I'm full of sh***.
The OP already said he knew what the problem is.

[mike stenson]

You ever look at reddit woodworking? At least half the beginning woodworkers show cross grain construction and are asking how to fix the cracking. The most common fix is fill it with resin, not that the construction was incorrect in the first place. Some guy just posted a barn door he made for a commission that was built incorrectly and the thing had a 1" gap from the bow. All I am saying is that poor instruction leads to poor craftsmanship. And they get that poor instruction from someone more concerned about youtube subscription numbers than teaching basic woodworking. I'm damned proud of my 50 years of woodworking (24 years professionally) experience and thought I can help teach others. As I said on the other reply, wood movement has been known for centuries!

Ya don't have to live up to your name in the process. It's called couth, maybe tact. But, now I'll just add.. Ok boomer.

[Luke Dupont]

Wow, this got a bit heated.

I actually understand Richard Coer's sentiment, even if I don't agree with it. I see the same thing in the Martial Arts world, where it is kind of justified, because you really can't learn a martial art just through video instruction and having never had any hands on experience with a teacher. You can learn some things, many even, but you'll be missing quite a lot without being able to feel the art hands on. So, it's an argument that I'm quite used to.

Does it apply to woodworking? I don't know. Unlike something like martial arts, you get feedback from your own work, not from another person. And the results of your work validate or invalidate your methods -- you simply need to not be so ignorant as to make mistakes and then not figure out why you made them / that they were in fact mistakes. Anyone who has done broad enough reading and research into traditional methods and has sufficient reasoning skills and sensitivity can do that. I am often surprised by how many little things I've learned and picked up on my own just through experience, feel, and reasoning about problems, which nobody mentions on, say, Youtube, but I see validated by nuanced discussions between very knowledgeable (and much more experienced than myself) people during in-depth discussions, such as sometimes occur on forums like this. So yes, reasoning skills, first hand experience, and research can certainly get you there without hands on instruction in the case of woodworking, I feel.

Here's what I will say:
If you are learning anything on your own from the internet, you have access to everything: from the best, to the worst. Discretion is definitely required. That said, I've always benefited greatly, as I think any intelligent and discerning person has, from the wealth of knowledge and experience shared via the internet. I read everything from books written over 100 years ago on the subject, to watching videos made by truly competent craftsmen of today.

There's also nothing wrong with making mistakes, so long as you learn from them. I knew not to glue things crossgrain like I did, even when I glued those pieces. I figured if it becomes problematic, I could always fix it. What I didn't know is that it could cause cupping and bowing in the way that it did, but now I do.

I often take a philosophy of not overcomplicating things, and it can be difficult in the beginning to tell the difference between refinements that are necessary as they avoid very real and likely problems, and those refinements which are just overengineering and overcomplicating things. I highly value the former, and despise the latter. I work as a software engineer, and am constantly battling with overly complex "clever" code that seeks to solve problems that don't exist. I see the same thing occur sometimes with Woodworking. So, I tend to sometimes err on the side of under-engineering, but leaving myself the ability to fix the problem if it does occur. This way, I learn a lot through experience what is necessary and what isn't. Everyone should seek to make these mistakes in the beginning, so long as they aren't selling their work or making things for clients (in which case, by all means, stick to the tried and true, by the book method first.), so that they truly understand why they're doing what they're doing, and not just taking everything on blind faith and randomly combining/applying "good practices" that they don't understand, and in contexts that don't make sense or are unnecessary.

[James Pallas]

Luke, You know about what the problem is and have at least started to think about a solution. The thing to remember is that the cross grain gluing may not be everything. The top itself may be cupping and believe me it has the power to do it cross grain or not. Just read about how many people have to flatten bench tops after they are built and in use. There are many ways to attach a top full length gluing to a cross grain stretcher is not a good one. Slots, buttons, dovetails, pegs etc. can eliminate the glue thing but that will not necessarily stop the top from moving. It is likely that you will flatten that top several times in the life of that bench. I would cut it loose re- flatten and put it back with a better attachment, easier to get loose. Be prepared to re-flatten in the future. You may get lucky and it will stay flat for a while until you move it.
Jim

[John C Cox]

All you have to do is look at furniture... All sorts of random grain patterns are used, and you seldom see cracks. Why? Mostly because they are designed to allow for movement. Flat sawn wood is mixed with quartersawn wood all over the place, and things are mostly ok. Breadboard ends are used on long grain pieces all the time.

Outdoors, things can be very different due to rain and sun.. But indoors, the humidity and temperature control we use for our own comfort reduces bad behavior in our furniture, assuming decent wood was chosen in the first place.

The thing is, unless the grain is nasty and unstable, wood is generally pretty decent stuff assuming it's properly seasoned... That's one of the reasons we don't use branch wood, curved logs, or "reaction" wood. That stuff never stays straight with humidity changes. It splits your joints, racks your cases, and generally plays hell getting anything to stay right. As an aside, it's also one of the reasons I hate pallet wood... Besides all the rocks and steel-barbed, spiral shank nails.

An example of this misbehaving wood... I have an african ebony fretboard blank that will never go on a guitar. It's perfect and black, but every time the weather changes, it takes a 1/2" hump about 1/3 of the way from the end.. Then the weather changes again and it goes flat. I've had it for the better part of 20 years and it's never settled down. Shame, as it would be beautiful.