If you haven't already figured it out dimensional lumber is not exact. One by is often 7/8" and 2" is not a full 2 inches so double check what you are buying. As I look at your needs I would get 8/4 and work from there.

Next, is the direction and type of grain critical to your design. For example a flat sawn 8/8 board ripped to expose the side of the cut will look entirely different than the front side. This is why most of us end up with lots of "scraps" as we cut the wood to fit our design from what is available.

I suggest you check you local supplier and work from there.

 

I think I'll probably do 8/4 plain sawn lumber so I get an interesting figure and can ideally get all 12 long pieces from the same board. This would allow me to have a continuity of the grain from slat to slat on the bench.

I think plain sawn walnut is probably more common anyway. I'll check with the lumber supplier to be sure.

 

Check around… My local lumber yard sells in 25/32 thickness, varying widths (and lengths, of course) on a lot of stuff. They probably carry 20+ different species like this. Some even quarter or rift sawn.

Depending on how flat you need, and how flat you can find at your local dealer, that kinda thing might work out for you?

Honestly, that 25/32 works out well when building most projects I do for home owners. They aren't paying for furniture quality stuff, unfortunately.

As for resawing your own, it would really depends on a couple of factors. If you get 4/4 and run it through the planer, you'd only need to run it across the table saw to get your 1 1/2" pieces. If doing the 8/4, you might need to mill a little bit more to get where you need to be. But, also the grain will look different… If your 4/4 is flat sawn, then you'll get flat sawn wood. If you're 8/4 is flat sawn, you'll end up with more quarter/rift sawn stuff.

 

Good advice here. Nothing to add to your question, but if you need 12 pieces, make 13 if you have the wood.

 

As wood moves so much after milling, you do start with pretty big wood. Work your way down and let is sit a few days until you are getting within trimming of your dimensions. Especially with 6 foot long, likely to get some movement that takes a lot of milling to get to a strait piece that is relaxed.

 

I usually adapt my project to the wood available, not the other way around.

See what you can get close to your initial plan and modify it where necessary.

 

Thicker lumber is more expensive. Buy 1×6's & you'll get 3×1-1/2" strips. The last walnut (recently) I got from my supplier was closer to 1" than 3/4 as S2S. Craftsmen Supply in Tampa ships.

Live edge walnut top overhang is 1/2" shallower than plan.
Did you know, or notice?

One thing us old timers do is not work to plan but adapt to the material at hand. How much of a difference will 1-3/8" or 1-9/16" make in the appearance of the final product? Say you went to 1-1/4" instead? This would get 4 pieces from a 1×6 instead of 3 at 1-1/2" increasing your yield by 1/3 for just a tweak of the dims. No one without a ruler and a copy of the plan is going to know that the dim you built doesn't match the plans. Don't obsess. Be willing to drift the dims if it saves materials.

Consistency & uniformity are more important than absolute dimension.

 

As wood moves so much after milling, you do start with pretty big wood. Work your way down and let is sit a few days until you are getting within trimming of your dimensions. Especially with 6 foot long, likely to get some movement that takes a lot of milling to get to a strait piece that is relaxed.

- tvrgeek

I was originally planning to

1. flatten the board face with hand planes
2. run the bottom through the thickness planer
3. use the track saw to create a straight edge along the length
4. use the table saw to rip long pieces slightly oversize. Each piece should now have four reference surfaces
5. cut necessary dadoes
6. glue up

Are you saying on step 4 I should actually cut the pieces well over size (maybe 1" by 2" instead of close to 3/4" by 1 1/2")? And then let the pieces rest for some days/weeks so they release tension, then mill all 12+ pieces on the four sides individually? Milling all 12 individually seems like a lot of work. I'll do it if it's important. I don't have a power jointer so it might be time consuming for me.

Thanks to everyone for the help. I won't obsess too much on the exact sizes. I want it to be close but not necessarily perfect. It seems the original design was based on the result of milling 8/4 or 4/4 stock to a finished size, so I think I'll be close to the original dimensions whether I try hard or not.