Work bench build question

[Daniel Hartmann]

I have a 7 ft long x 18" wide x 4.5" thick slab of cherry that I want to incorporate into a roubo or Roy underhill French bench roubo with a tool tray. The slab is 10% MC but it contains the pith. My question is, should I rip the pith out or leave it since the slab is dry? I don't have a table saw so I'd have to rip the slab on a bandsaw 😁. What do you guys think?

[Jim Matthews]

Doesn't the pith eventually shrink and loosen?

I don't know anyone that builds with it in place.
You should be able to get at least two quartersawn boards from this.

FYI - The Cherry I use is pretty soft stuff. It won't stay pretty for long as a benchtop.

[Daniel Hartmann]

Thanks for the reply. This is a big slab with the pith running the length of the slab. I don't see how it could loosen and fall out. I know cherry is fairly soft but I have this enormous dry slab and need a workbench!

[Jim Matthews]

http://www.renaissancewoodworker.com/large-timbers-for-workbenches/

I don't have first hand experience with this, but have been warned off leaving the pith intact.

At a minimum, I would recommend ripping out the pith and replacing the center with some sort of batten.
Bob Rozaeiski at the Logan Cabinet Shoppe has a similar design and another recent build shows a similar apparatus.
(Ken Hatch made his (http://www.sawmillcreek.org/showthread.php?221003-Another-Bench-Thread&p=2302861#post2302861) offset, and I will emulate this on my next build.)

This will allow you to pin two sides to the supporting trestles, in the "center" of the span and allow some seasonal movement.
Cherry will shrink 4% across the grain, maybe more if your shop is dry.

A 30" span may shrink as much as 1 1/2 inches over the course of the driest season.

A big, thick slab like this will exert considerable force as it moves through the Spring and Fall humidity range.

How long has this slab been in your shop, where it will become a bench?

I'm not saying it can't be done, but you're inducing two variables (pith shrinkage and slab movement) in a workbench.

[Todd Burch]

If you are at 10% MC, I don't think a whole lot more moving is going to happen, and if the pith is hasn't shown signs of loosening yet, I can't imagine what conditions it would have to go through to shrink so much it separates from the surrounding fibers.

I've seen the most unusual woods, "softer than the should have been", used in areas I would not have. For instance, I've seen eastern red cedar used as stair treads. Who would have thunk.

If you want to use cherry, use cherry! I think it will look awesome.

With a workbench, it just might have to have it's top reworked at some point in its life anyways, no matter what you make it out of.

Let's see a pic!

Todd

[Dave Richards]

If you're concerned about the pith, you could rip it out and use the resulting planks with a gap in the middle. That gap could be useful for clamping.

[Jamie Buxton]

I wince at the thought of that wonderful big cherry slab being used as a workbench. I'd save it for furniture, or sell/give it to somebody who's going to use it for furniture. Make the bench from something less gorgeous.

[Daniel Hartmann]

Thanks for all the replies. The slab is at 10% and for the next two years it'll live in a climate controlled basement that stays at 45% RH year round. I'd love the use the slab for furniture too but it's not often you find such a big, dry nice hunk of wood and most importantly it only cost me, $150. The guy I bought it from had four of them and I tried to buy them all.

[Frank Drew]

I wince at the thought of that wonderful big cherry slab being used as a workbench. I'd save it for furniture, or sell/give it to somebody who's going to use it for furniture. Make the bench from something less gorgeous.

I had the same thought as Jamie: I see stock that thick -- assuming it's nice stuff -- and I'm thinking turned farmhouse or trestle table legs; table columns; bed posts; large turned bowls; etc.. Any old wood can make a bench top but solid 16+/4 in a nice timber, especially if its width is a generous 4x multiple of its thickness, isn't something you see every day.

[daniel lane]

Christopher Schwarz made a Roubo-type bench with a thick slab of cherry for the top, and I thought it beautiful. Furniture for the workshop. Daniel, I'd be doing what you're doing, don't listen to these other guys! :)


daniel

[Daniel Hartmann]

I actually emailed him about this bench for that reason. His cherry roubo is gorgeous.