Monday, January 16, 2012

News Flash: Maple is Not as Soft as Poplar

I had planned to build a poplar base for my Roubo workbench.

But wise friends talked me out of it, arguing that poplar would never hold up to the cherry top considering that the bench would be broken down for transport on occasion.

They were right of course, so I chose soft maple instead.

I started cutting the through-tenons and dovetails on the legs this weekend and figured I'd have all of them cut and squared up by end of day Saturday.

By Monday afternoon, two legs were finished.  And I have concluded that "soft" maple is, in fact, anything but.

Theoretically, the tenons and dovetails will fit snugly in their matching mortises, but not so tight that they can't be knocked apart.

This is going to be tougher than I thought. Maple is unyielding. So in order for all the pieces to fit, they must be square and flat.

In other words, I fully anticipate that there to be gaps in the joints once the bench is finished.

20 comments:

Marilyn in Seattle said...

I've come to embrace my gaps .. dents, patches and the like (see the doh! files on my last post). :OD

kelton said...

Thats going to be a beautiful bench. I made mine out of laminated pine, but trust me, once you get the top on you arnt going to want to ever take it off.

Brian said...

Bizarre as it may sound, I'd have gone with red oak for the legs. It's got a good weight, works easily, and is relatively cheap in your parts.

But at least soft maple is still relatively heavy.

Jonathan Szczepanski said...

I am using some "soft" maple on my current project. I was deciding between soft maple and poplar, because it is going to be a painted piece. I think I chose wrong. While the maple is harder, that hasn't been my problem with it. I think it tears-out, chips and does other unexpected things much more then I anticipated. Oh well. Live and learn.

Jonathan
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James Owen said...

Looking really nice so far, Kari! It's going to be a beautiful bench.
The maple may be a bit more difficult to work, but it is very durable, and five years from now, you'll be really glad that you chose maple over poplar.
Really enjoyed your build documentation photos!

Kari Hultman said...

Marilyn, we might as well embrace them. It's highly unlikely that anyone of us will ever achieve perfection. ; )

Kelton, I'm not so sure I'll be able to take the top off even if I want to. Theoretically, my design will work. In reality, we shall see...

Brian, I've never worked with red oak, but it is readily available. I bet a lot of hardwoods would work well for bench material. I have yet to see an ebony or pink ivory bench, though. heh

Jonathan, I haven't had any tearout with my maple. Maybe I just got some really nice boards. It machines and handplanes really well. Next time you need some hardwood, come on up and we'll take a road trip to Groff's.

Thanks, James. I'm sure you're right about the maple. This is the bench that's supposed to last me the rest of my years and hopefully a couple more generations.

Jonathan Szczepanski said...

Kari -

If you ever need to get the top of your workbench off, a carjack comes in very handy. :-)

A road-trip to Groff's hmmmmm....

Jonathan
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thekiltedwoodworker.com said...

It's obviously hard work, Kari, but you make it look easy. :)

Good luck with your bench build!

mcglynnonmaking said...

Great update Kari. I'm using doug fir for mine, and except for the knots it's not too bad to cut and plane.

The tenons came out looking great, as soon as my leg stock dries out a little I'll be cutting those same joints myself.

Anonymous said...

Kari-Your tenons look great! Nice work. But, come on, are those really the hands of a woodworker?
Nicely shaped fingernails, no bandaids and where's the stain under the fingernails? LOL! If I came home from the shop with no stain under my nails, my wife always asked, "Did you go to work today?" Frank

woodcanuck said...

Wow...nice legs! :-)

I'm so glad your covering this, I will be living vicariously through you for a few weeks as I get ready to do the same thing.

If you didn't have floats, what would your next go-to tool be for cleaning up the tenons? I am anticipating some sloppiness on my part.

Ian

Frontier Carpenter said...

It's a workbench after don't worry about gaps have fun with it.

mokusakusensei--woods teacher said...

According to "The Wood Data Base", Basic Specific Gravity of poplar: .40 Hardness
Basic Specific Gravity of silver maple: .44 Hardness
and "The term “Soft Maple” is merely used to differentiate these species from Hard Maple."
I believe that there are many benches that have pine as leg members. I believe that anything, if constructed correctly will be more than adequate for the base.
My two benches that I built for my sons ended up weighing only 220lbs. The first bench had doug fir legs.(the wood was free) The second bench used poplar. I would think that either will hold up very well for many decades. IMHO
Your work looks really nice. My son picked up his bench yesterday. I miss using it already.

Jeremy Kriewaldt said...

My RnRoubo TM (Rough and ready Roubo) bench has gaps all over the place. Since I am not going to knock it apart deliberately (the quality of my joinery makes it quite possible that it may happen accidentally), my plan is to allow sawdust and other woodworking detritus to gather in the cracks and then squirt in some thinned down yellow glue to create a solid filler - not elegant but easier than trying to get rid of the gaps by neater joinery!:)

Kari Hultman said...

Jonathan, thanks for the tip!

Thanks, Ethan. I may need to use that good luck.

McGlynn, by the looks of your timber, your bench is going to be massive. The nice thing about douglas fir is you can get it really thick so you don't have to glue up any boards.

Frank, the nice nails are evidence that I eschew housework. :D

Ian, you can use chisels, rasps, and files to do the same job as floats. My rasps and files aren't cutting very well and should be replaced. That's why I grabbed the floats. Good luck with your bench!

FC, you're right. And in ten years when the top's all banged up and I've spilled soda all over it, I probably won't even notice the gaps.

McKay, poplar's great, but since my bench will be taken apart on occasion, there was a concern that the tenons and dovetails would become compressed, dinged, or otherwise damaged with repeated breakdowns. Seems like the maple will hold up better. In fact, it may give the cherry benchtop a few bruises.

Jeremy, I think I'll borrow that trick anytime someone comes to visit my shop. Thanks!

Anonymous said...

Kari I really love your choice of using hand tools over power tools. You easily could have chosen power tools but seeing you use the tenon saw and chisels shows the love of a true wookworker.

Brian said...

Beautiful work. But I think you are right that this style of bench might not be reliably portable. If the through tenon joints are tight enough to provide a steady bench, seems like even a fairly mild increase or decrease in humidity over even a short time is liable to make them pretty much stuck, or too loose to hold properly in the top. Though maybe sealing the endgrain with a couple of coats of epoxy resin would cut down on the short-term movement quite a bit.

Kari Hultman said...

Anon, it's been fun working with hand tools to get this far. I'm not sure how I could have cut them otherwise because the boards are so big and heavy. Hand tools saved the day!

Brian, I have my fingers crossed. I'm building this for a presentation in April and hoping that it'll work as a transportable bench. I'm more concerned about the cherry moving with the seasons than I am the maple, but it only takes one of them to throw this out of whack.

Brian said...

Kari, you have been at this longer than I have, but for instance I have a rosewood mortise gauge that I keep in the house because if I leave it in my new, and as yet unheated, shop in the winter, it will swell to the point where I can no longer move the fence. The clearance is maybe 1/32" and it only takes a day or two for the wood to pick up the extra moisture. I was amazed how fast it went. But thinking about it, traditional woodwork is built to take movement into account, the tolerances on things like sliding lids or drawer fronts are big enough to allow the wood to swell and shrink without binding, and the ambient humidity in a room changes slowly so I think we don't notice how fast it can go.

Kari Hultman said...

Brian, you're right about that. My 9"-wide cherry tool cabinet moves an entire 1/4" throughout the year. I'm building the top of my bench so that the two top boards have a gap in between them. There will be a stretcher beneath the benchtop on the end assemblies to support the top. This means that only two of the legs need to fit each board, instead of all four needing to fit into the top. I plan to keep an eye on the gap in the middle of the top to see when it moves. I'll keep knocking the top boards off and plane one or both of the inside edges so the gap never closes completely. I can also tweak the fit of the legs into the mortises at the same time and also wax as needed. By next year at this time if the legs have become too loose in the mortises due to tweaking, I can decide to shim and glue them (making the bench no longer transportable) or figure out some other way to tighten them without losing the knock down feature.