What percentage goes to waste?

[Andrew Thuswaldner]

I realize it depends on how straight the stock is and other factors but I would like to know what you use as a guideline for calculating how much wood you need to build a work-bench assuming you will joint and plane stock to get it straight and flat. I plan to build a Roubo style work-bench and I have calculated that the jointed and planed pieces prior to assembly will amount to about 103 board feet. What should I expect to start with, 25% excess or more?
Thanks, Andrew

[Larry Edgerton]

I always use 20% as a general rule when bidding, unless there is circular work, and then I add 10-20 percent to that depending on how it will be constructed.

[Myk Rian]

20% is the rule of thumb, but I like 50%.

[Jim King]

When I produce 1/4 inch finished boards from rouigh cants I loose 75%.

[David Keller NC]

I think this specific question has a great deal to do with the source material you intend to use. If it's construction-grade SYP, I"d plan on about 35%-45% waste even if you're careful about picking it at the lumber yard. One reason is that if you're going with the Schwarz' recommendations, then you're cutting the top wood from 2X10's or 2X12's, and you're going to have to cut around knots.

[Peter Quinn]

I'd estimate 15% waste if the stock is decent. You can bury a few imperfections in the body of a lamination like that, and you can certainly use stock with imperfections for legs and frame members. The worse the stock gets, the higher the waste obviously. On a project like that if I'm using KD hardwood and the lumber yard is close, than the biggest danger of coming in under is having to acclimate a bit more stock and I'd be a bit more conservative with the BF total. If you're using SYP, and have to air dry it to finished MC, and that stuff tends to go nuts when sawn and milled, I'd go way over, because you don't want to wait 6 months to dry more stock in a pinch.

I personally would rather work on the floor than work with SYP, and am planning a similar bench build this summer using wither red oak or ash, or some of both.

[Andrew Thuswaldner]

Thanks for all the input. We don't have SYP in Canada so I'm looking at some Ash or Maple from one of our local stores, KJP Select Hardwoods or Adams and Kennedy Wood Source. From what I have seen at those stores I can get stuff that is without knots. Peter I have not considered red oak but maybe I'll look into that. It's not as stiff as either Maple or Ash but maybe is would be suitable for the legs and stretchers. Anybody think the Schwarz 4" thick top is over-kill in a hardwood? Thanks again for the input.
Andrew

[Matthew Hills]

I realize it depends on how straight the stock is and other factors but I would like to know what you use as a guideline for calculating how much wood you need to build a work-bench assuming you will joint and plane stock to get it straight and flat.

A lot will also depend on the sizes you get.
The Benchcrafted folk recently had a short column on this topic.

They noted that 5" and 10" widths were ideal for their design; a more typical 6-7" board width would result in a lot of waste on their design:

You’re going to need about 150 board feet of rough 8/4 lumber for the bench. If you’re able to pick through the lumber at your local yard, try to find boards for the top that are either around 5” wide or at least 10” wide. This is usually enough to straight-line rip and joint the boards for the top. If you end up with a bunch of boards around 6” or 7”, you’ll end up with a lot of waste when you rip the boards for the top, and you might find yourself short on stock as the project moves along. When we build this bench we order 200 board feet of 8/4 stock, straight-line ripped and skip planed. We do have some leftover, but this comes in handy for building accessories and other projects. The best way however is to make up a rough list of what you need from the measured drawings and pick through the stack at the yard for the best boards.

Matt

[Lee Schierer]

I total up all the inches of material I need and head to my lumber supplier. He has only dimensioned clear hard wood stock. I buy what I need to the nearest length the lumber yard has on hand. When I get home, I measure each piece exactly and enter the lengths in to my optimization program (Sheet Layout) and let it figure the best way to cut the pieces needed from what I have. I rarely have to make an extra trip for more material and usually that is because I messed up a piece. My scrap pieces are usually less than 6-8" in length.