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measuring board feet when purchasing rough sawn lumber

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Forum topic by robdew posted 02-27-2009 08:45 PM 9835 views 0 times favorited 11 replies Add to Favorites Watch
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robdew

84 posts in 3180 days


02-27-2009 08:45 PM

When I am purchasing rough-sawn lumber that is cut to a variety of thicknesses, what is the usual convention for board thickiness for BF calculation?

I know milled lumber usually rounds up 13/16 or 7/8” to 1”. Does rough sawn do the same or is it actual thickness?

I am considering purchasing some rough sawn lumber from someone locally who usually doesn’t deal with this (because the price is very good) and hence it’s not all 4/4 or 8/4, etc.

As usual I can’t figure out what the appropriate forum is for this question, so I will ask it here.


11 replies so far

View mountainsky's profile

mountainsky

29 posts in 2863 days


#1 posted 02-27-2009 09:11 PM

If no surface is planed, you should be buying actual thickness….........

View CharlieM1958's profile

CharlieM1958

16243 posts in 3684 days


#2 posted 02-27-2009 09:16 PM

If the lumber you are looking at is rough sawn to 1” thick, you wouldn’t round up. A board that is 1” x 12” x 12 feet long would equal 12 board feet. The reason surfaced lumber is actually smaller than its board foot calculation is because that calculation is based on the rough sawn size.

Am I saying that clearly enough?

-- Charlie M. "Woodworking - patience = firewood"

View Darell's profile

Darell

433 posts in 3060 days


#3 posted 02-27-2009 09:24 PM

thickness x width x length divided by 144 equals board feet. Keep in mind what Charlie said about rough sawn size.

-- Darell, Norman, Ok.

View PurpLev's profile

PurpLev

8523 posts in 3114 days


#4 posted 02-27-2009 09:31 PM

when lumber is being measured for BF it is measured by the rough sawn surface – so when you buy rough sawn lumber you pay for it’s current size…

If you buy lumber that was milled – you’d be paying by it’s ‘original’ rough sawn size – thats why you get ‘less’ material for a given measurement when it’s pre-milled.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Scott Bryan's profile

Scott Bryan

27251 posts in 3287 days


#5 posted 02-27-2009 09:37 PM

One additional thought on the subject is that rough sawn 4/4 stock is usually sold at 1 1/8” in thickness and accordingly, 8/4 rough stock is usually 2 1/4” thick. For the purposes of calculating bf simply use Darell’s formula and substitute 1 for thickness of your 4/4 stock and 2 for 8/4 material. And, this formula assumes that both the width and length measurements are in inches.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View robdew's profile

robdew

84 posts in 3180 days


#6 posted 02-27-2009 11:04 PM

this cleared it all up thanks!

View David Freed's profile

David Freed

112 posts in 3133 days


#7 posted 02-28-2009 05:26 AM

“One additional thought on the subject is that rough sawn 4/4 stock is usually sold at 1 1/8” in thickness and accordingly, 8/4 rough stock is usually 2 1/4” thick.”

That is only true if it is green, and even then that is on the thick side. If it measures that thick after it is dried, it is a miscut.
This was discussed a few days ago here – http://lumberjocks.com/topics/6510

-- David, Southern Indiana

View HossMan's profile

HossMan

42 posts in 3184 days


#8 posted 02-28-2009 02:35 PM

”...thickness x width x length divided by 144 equals board feet.”

I just want to clarify that this formula works if the length is measured in inches. If length is in feet, then the formula is thickness x width x length divided by 12 (twl/12)

kinda nit-picky, I know…....

View HeirloomWoodworking's profile

HeirloomWoodworking

238 posts in 3205 days


#9 posted 02-28-2009 03:32 PM

I wonder if I might add a question to this thread.

In my area there are no local mill sources. I have always purchased my hardwood S3S (surfaced face, back and 1 edge) from the small local lumber yards. I have used a surface planer (13 1/2”) to plane my materials smooth and consistant.

I am considering venturing into purchasing “rough” lumber.

When buying rough lumber will my existing surface planer properly plane and true this material?

I have also seen several terms used for rough lumber…hit & miss planed. skip planed etcetera.

Thanks in advance for your replies & advise.

Trev

-- Trevor Premer Head Termite and Servant to the Queen - Heirloom Woodworking

View Boardman's profile

Boardman

157 posts in 3227 days


#10 posted 02-28-2009 04:20 PM

Heirloom – The planer will only render the two surfaces PARALLEL. If you plane both sides of a bowed board you’ll end up with a bowed board with 2 nice parallel sides. You’ll need a jointer to render it truely flat before planing – you only need to get one side flat and the planer will take care of the other side.

Hit/miss or skip planed means they ran both sides thru a planer, but don’t guarantee a 100% clean surface on either side. To what degree they’ll be cleaned up varies by supplier. I get skip-planed oak from a lumber yard and most of the time it’s completely cleaned up at about 15/16th. But – it won’t be flat necessarily.

Purely “rough sawn” lumber has not been planed at all.

View miles125's profile

miles125

2180 posts in 3471 days


#11 posted 02-28-2009 04:37 PM

Most all projects you see in lumberjocks call for wood to be surfaced to ensure its flatness. Nobody but the end user does this. So it makes sense to buy boards in the rough to get maximum plumpness for this task.

-- "The way to make a small fortune in woodworking- start with a large one"

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