8/4 sawn wood

[BarryC]

What do the numbers 8 and 4 mean? And please don't laugh too hard I really don't know. One of these days I'll have enough experience to consider my self a rookie...

 

[jeff...]

What do the numbers 8 and 4 mean? And please don't laugh too hard I really don't know. One of these days I'll have enough experience to consider my self a rookie...

Barry to answer your question without much rabbit chasing. Say eight quarter, not to state the obvious but there are four quarters in an inch so eight quarter would be 2 inches, twelve quarter would be three inches, etc...

Easy enough... Now the more difficult to understand (and explain)

 

[sediener]

Those designate the thickness in quarter inches.

8/4 = 2 so it is a little over 2" thick.
4/4 =1 so it a little over 1" thick.

Good sawyers give you a bit over the actual 1" or 2" to account for shrinkage during drying.

- Steve

 

[BarryC]

Thats easy enough! So neither number has anything to do with width? How would an 8/4 that is 5 inches wide be noted? 8/4 x 5? or am I over complicating this?

 

[walnutjerry]

Thats easy enough! So neither number has anything to do with width? How would an 8/4 that is 5 inches wide be noted? 8/4 x 5? or am I over complicating this?

Barry---------you have stated it correctly.

Lumber grading and terms can be confusing when you are not familiar with the terminology. Go to the National Hardwood Lumber Association site and browse the standards for grading etc. I think there is a glossary on the site but not sure. Been a while since I browsed the site.

http://www.natlhardwood.org/

Jerry

 

[Bas]

I don't think there's a real standard for describing the width and length. A typical description for lumber is "8/4 hard maple, 8-10' long, 4-7" wide" Boards are never uniform, the thickness is typically the only "constant" when buying a load of lumber.

Generally, boards are between 6'-10' long, and 5" - 10" wide. Longer/ wider boards sell for more, shorter/ narrower boards sell for less.

(Of course, _some_ people insist on 40ft boards for their projects.....)

If you got all that, ask about board feet You may also want to check out episode 4 on http://thewoodwhisperer.com/

 

[jeff...]

whoops hit the Submitt Reply button by mistake (my secret to high post count :lol

Anyways on a saw mill there are usally 3 scales

* a regular inch scale graduated in 16ths of an inch
* a softwood quarter inch scale
* a hardwood quarter inch scale

Width and general cant sawing, the guy running the saw mill will use the regular inch scale ok - so I have a bunch of 6" wide boards to cut I use the inch scale for width. If I'm cutting softwood I use the softwood quarter inch scale for thickness. lets say I get an order for a bunch SYP 1x6's I would use the regular inch scale for my width and the softwood quarter inch scale for thickness. Why because when softwood is dry and has finished drawing up, I could expect a finished board of 3/4" thick by 5 1/2" wide... Softwood like SYP, Hemlock, Spruce, Cedar, etc... rarely is kiln dried to anything below 15% moisture content. So the Softwood quarter inch scale will saw to a thickness of 1" ~ 1 1/8", so when the lumber shrinks it will dress out @ 3/4" thick. If it don't make 3/4" then it's considered cull.

The hardwood scale is the same principle but it will leave a thickness of an 1/8 to a 1/4" over. So freshly sawed off the log (NOT Kiln Dried) 4/4 would measure 1 1/8" ~ 1 1/4" Hardwood is usually dried to 6 ~ 10% moisture content thereby shrinking even more than softwood. So you need to start with a thicker board fresh off the log to meet your final thickness target once the lumber is fully dried.

Here is an easy way to remember thickness take a fresh cut board, measure it's thickness and subtract 1/4 for softwood and 3/8 for hardwood. Assuming proper during technique is used that will be your finished thickness.

Also another easy way to remember dry lumber is subtract 1/4 for a final target thickness and 1/2 for width when looking at dry rough cut lumber. So lets say your looking at a kiln dried rough cut board that was cut @ 4/4x6 when it was sawn off the log. The board will probably measure a little under 6" wide and right around 1" in thickness. By the time you joint and plan the board it should clean up to a min of 3/4 x 5 1/2 - if it cleans up thicker thats better for you but a minium of 3/4 x 5 1/2 is the rules.

One thing I caution folks on is buying green lumber that is miscut... 4/4 hardwood should measure 1 1/8 to 1 1/4" and softwood 1" ~ 1 1/8". Make sure your saw mill guy is using the right scale and not just cutting by the regualr inch scale or you'll wind up with a bunch of 5/8 ~ 1/2" thick boards and get ticked off :-x.

Thanks

 

[DavidF]

excellent post Jeff, clear as a bell.

 

[Kyle]

That is assuming all your wood is uniform, knot free and equipment is 100% in tune. It also makes a difference on the type of blade and the tension applied as well as the lubricant.

We sawyers all know our blades never waiver and tension is always 110%


For hardwood I use the grade scale which is 1 and 1/8" for a 4/4 board. On a woodmizer that scale is already set as standard on your machine on others I dont know.


For softwood I use actual measurement for scale. It is graded differently than HW.

 

[jeff...]

We sawyers all know our blades never waiver and tension is always 110%

Yeah never any wave, always sharp, never a tooth off pitch - In my dreams :eyeslam: