Large slabs from wonky woods.

[Aeneas61]

I have a buddy wanting a slab for a roubo style workbench, which means something about 5 or 6" thick by say 24" wide 8 feet long. Around here most large oaks are too valuable to use for this, but there are a lot of large sycamores and black gums, as well as hemlocks.

Has anyone had experience cutting large slabs from Sycamore, black gum or hemlock, or maybe some other low grade wood like beech or maple?

Thanks all
Josh

[Ianab]

Aren't most of those benches made by gluing up laminations? Like you start with a head of 2x6s, and end up with a solid glued up top?

I guess you could saw a solid top, but it will take a LONG time to dry.

If you saw a heavy slab of a wood that's difficult to dry, and moves a lot in the process, it's almost certain to tear itself apart as it dries, especially if it's less than straight grained. Sweep, crotch wood, knots, off centre pitch (all the things that make a log "wonky") just make the problem worse.

Hemlock might be the most stable of the ones you list? Not sure how it will work for a bench top though, might be a bit softer than ideal.  But at least you would have a fairly good chance of getting it dry, intact and in our lifetimes.  :D

But I'd try and convince him to do a glue up, then you could probably quarter saw a large Sycamore into 2" boards than you should be able to dry intact and go from there.

[Aeneas61]

many people do glue up laminations these days, traditionally they were made with a solid slab split or sawn from a log, and they didn't really let it dry before building, the legs and everything are tenoned into the top and hold it some as it dries over a few decades.

[woodworker9]

As stated, a "traditional" Roubo style bench was made from a single solid slab, 5" thick or so....

I made mine from glued up 8/4 and 12/4 maple.  Great bench, and very heavy, which is what is needed if you're doing a lot of hand work (only reason to build that bench).  Ash is also a great wood, and with the EAB, the logs are literally "all you can eat" around here for free from the tree guys.  Big ones, too.  I've got a stack of 12/4 that will end up being another workbench for my new shop, as well as table tops. 

Ash and white oak are really good, light colored woods for a workbench, and they're reasonably stable.