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Forum topic by tooold posted 02-11-2009 10:08 AM 1615 views 1 time favorited 16 replies Add to Favorites Watch
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tooold

56 posts in 3148 days


02-11-2009 10:08 AM

Topic tags/keywords: question

Could someone give me a quick rundown on what the various sizing designations mean – 4/4, 12/10, etc? I’ve tried applying my brain to it, but it doesn’t stick. And I’ve searched all over the place, but no luck.

Thanks!

Myles


16 replies so far

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ProbablyLost

83 posts in 2979 days


#1 posted 02-11-2009 10:20 AM

4/4 = 1” thick 8/4 = 2” thick etc…. the second number represents quarters like 1/4 = 1/4”. These numbers represent how thick a board is.

-- Chris

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tooold

56 posts in 3148 days


#2 posted 02-11-2009 10:26 AM

Thanks, Chris, that was one of the possibilities I came up with, just didn’t know if it was the right one. So, the “X/10” would be for metric measurements, I’m figuring…

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Mike Morris

27 posts in 2854 days


#3 posted 02-11-2009 10:30 AM

Myles,

No such thing as a dumb question. I’m assuming your referencing lumber/hardwood sizing. Here’s the link to the wiki page on lumber which covers dimensional lumber sizing conventions.

http://en.wikipedia.org/wiki/Lumber

Hope this helps.

Mike

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ProbablyLost

83 posts in 2979 days


#4 posted 02-11-2009 10:35 AM

I have never seen any x/10. the only 10 I have ever seen was a 10/4 (2 1/2”)

-- Chris

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ProbablyLost

83 posts in 2979 days


#5 posted 02-11-2009 10:37 AM

It could be that way in Europe….. just not sure

-- Chris

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tooold

56 posts in 3148 days


#6 posted 02-11-2009 10:41 AM

I might have mixed it up with 10/4, can’t remember… not unusual!

Thanks for the wiki reference – didn’t think to look there…

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groland

152 posts in 2873 days


#7 posted 02-11-2009 07:05 PM

I believe these designations should be for unfinished lumber. 4/4 is 1 ” thick unfinished. Once the stock is planed to remove saw mill marks and squared for use, it will be something under 1”, probably averaging more like 3/4”

George

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JimmyC

106 posts in 2863 days


#8 posted 02-11-2009 07:19 PM

Actually I think 4/4 rough is 1 1/8”, so that it can be skip planed quickly down to 1” for sale, at least that’s how it works for hardwoods. Softwoods and construction lumber are a little different. At least this is what I’ve been told by my local sawyers.

Jimmy

-- -JimmyC...Clayton,NC- "Just smile and wave boys, smile and wave"

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kolwdwrkr

2821 posts in 3051 days


#9 posted 02-11-2009 08:31 PM

Like JimmyC mentioned about 4/4 ROUGH is 1 1/8” or so. However if you order material surfaced 4/4 would be 3/4 or 13/16 ~ give or take. So if you tell the lumber yard you want it to be S2S keep in mind it may not be what you expect.

-- ~ Inspiring those who inspire me ~

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PurpLev

8523 posts in 3110 days


#10 posted 02-11-2009 08:33 PM

JimmyC I always thought that 4/4 is what it is -that it’s measured 4 quarters… I stand corrected if thats the case…

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

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David Freed

112 posts in 3129 days


#11 posted 02-11-2009 11:52 PM

4/4 rough and green is sawn 1 1/16” to 1 1/8” to allow for shrinkage when drying. Kiln dried rough 4/4 is supposed to measure a full 1”, although slightly thicker is fairly common. Dry lumber thinner than 1” is considered a miscut. Dry lumber that measures 1 1/8” is also considered a miscut. It will not dry at the same rate as properly cut 4/4, and it costs the sawmill money because it lowers the yield from the log.

-- David, Southern Indiana

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jm82435

1284 posts in 3203 days


#12 posted 02-16-2009 08:02 PM

I think it depends on the source, if I get my lumber from a specialty (lumber only) supplier 4/4 S2S is ~15/16”. If I go to the local lumberyard (builders supply) what they sell as “1 inch” stock is actually planed to 3/4”. (YMMV)...

-- A thing of beauty is a joy forever...

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David Freed

112 posts in 3129 days


#13 posted 02-17-2009 03:37 AM

jm82435,

You are talking about surfaced lumber. Both places that you mentioned started out with the same thickness. The quarter system is a national standard that doesn’t vary. Surfacing lumber is done to suit the customer.

-- David, Southern Indiana

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JimmyC

106 posts in 2863 days


#14 posted 02-17-2009 05:26 AM

There seems to be a difference in sizes of 4/4 in hardwood, as I said my local sawyers here in NC cot 4/4 to 1 1/8” green. they say that’s to make up for shrinkage :>). Usually when it drys it’s a little bit over 1” rough and as was pointed out by kolwdwrkr, it usually becomes 13/16” S2S. There’s an article on woodweb about grading rough lumber that helps, but still doesn’t clarify an absolute dimension. I would be leary of purchasing 4/4 rough dry lumber that was anything at all under 1”, because it may not dress out at 3/4”.

Jimmy

-- -JimmyC...Clayton,NC- "Just smile and wave boys, smile and wave"

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David Freed

112 posts in 3129 days


#15 posted 02-18-2009 03:46 AM

What I said in my previous post is not hearsay or local custom. I graded lumber for over 4 years and I have the NHLA grading book that states what the requirements are. NHLA rules are the same nationwide.

Some mills have older model circle saws that aren’t as accurate as the newer bandmills. They will try for an average of 1 1/8”, and their lumber will vary from up to 1/16” over and under the 1 1/8” they are trying for. Lumber buyers deduct less for a thick miscut than for a thin miscut, so these mills err on the heavy side.
Bandmills are much more accurate which allows a thinner target thickness. Most vary only about 1/32” or less, which allows them to set their mill for an average thickness of 1 3/32”.

-- David, Southern Indiana

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