My first try working with oak

[lcm1947]

I am making a sled for my router table and decided to build one the American Woodworkers " Woodworking with the Router " had suggested. In doing so however they suggest using for the brace and flange different kinds of oak. One is 8/4 and the other is 6/4 and even another one that is 5/4. What is all this X/4 business anyway? I imagine it's the quality of the oak but don't really understand it. Anybody out there that can explain it? And also why in the world would you go to the trouble of using 3 different grades if that is what it is.

[DUD]

Mac
The way wood is measured and sold is scary to the layman. As I understand it 4/4 is an inch, so If I am right You can figure from there. Bill

[Deadhead]

I believe they are referring to thickness: i.e. 8/4" = 2"

[GeekMom]

The numbers are referring to the pre-surfaced thickness of lumber. This article shows the equivalent measurements after surfacing.

[lcm1947]

Thanks for the info and site. Kind of a weird way to refer to it but what ever? Thanks again for the info.

[gsmittle]

Thanks for the info and site. Kind of a weird way to refer to it but what ever? Thanks again for the info.

No profession wants the civilians to know what they're talking about.

g.

[LCHIEN]

Thanks for the info and site. Kind of a weird way to refer to it but what ever? Thanks again for the info.

There are basically 2 kinds of lumber - One - dimensional lumber usually softwood pine sold for construction in your standard 2x4 1x4 2x6 etc sizes (that are not really but close to 2" x 4" but that's another story). Most of what you find at Lowes, HD, etc is dimensional lumber, and what hardwoods they have are usually sold more like dimensional lumber to make it easier for novices.

Then they sell hardwoods, in non-standard sizes. This includes virtually all Oak, walnut, cherry, mahogany, maple, etc. You find these at specialty hardwood lumber stores and at woodworking specialty places like Rockler and Woodcraft.
Thickness is listed in 1/4ths before finishing, thus 5/4 is 1-1/4" think before planing, probably 1" to 1-1/16th after planing. 8/4 is 2" rough cut or 1-3/4" or more when planed.
Also there are no standard widths and lengths, usually sold in "random lengths and widths". surfaced (planed) on 2, 3, or 4 sides. sold volumetrically, in board feet (144 cu inches) before any finishing.
A whole world to learn. This has been gone over many times here and I think its in the FAQ, too.


Good luck.

[lcm1947]

Thanks Loring. I still think that it's an odd way to refer to wood but until I'm in charge of the world I guess there's not much I can do about it.

[just4funsies]

That's where the term "quarter-sawn" lumber comes from...

[GeekMom]

Actually, I think it refers to the way the tree has been sliced, rather than the thickness of the boards.

Quarter-sawn A method of cutting lumber where the annual rings are relatively perpendicular to the face of the board. Quarter-sawn lumber tends to be more dimensionally stable than other forms of lumber, such as plain-sawn.

Plain-Sawn Lumber A method of sawing lumber where the log is cut tangential to the growth rings. Also called flat sawn when referring to softwoods.