Square feet vs board feet and the Doyle rule question

[GeneWengert-WoodDoc]

No problem.

There is really an issue when we figure cubic feet per BF.

Also, due to the smaller size of softwood lumber we find that we can get around 18 bf per cubic foot  with 2x12s ... and hardwoods about 11 bf per cubic foot.  That certainly affects Doyle, Scribner and International overrun.

[Schramm]

Thanks everyone I guess the best way to figure out the true yield is to go and pick up a couple and cut them and see what I get.  I understand about blades dulling faster but honestly the cobalt blades are made for this exact situation so it is better then just a normal blade.  I have 8 14" round white oak logs coming tomorrow or Tuesday and I have decided to set the mill up in my backyard in the house that I am living in right now as my back yard is level and large enough to handle what I am doing but the best part it is fenced in, so no one can get to it.

I think I have a grasp on what you guys are talking about and if I was to guess a 10" x 10" x 10' log may only yeild 6-7 good pieces that will be quality lumber.  I guess I understand since it is reclaimed or old wood which as been attacked by the elements for many years.

Thanks again all.

Rob

[Schramm]

Ok since we are on the subject of yield, let me ask about the 14" round white oak logs that I have coming in.  These to are 10' long and I am looking again at the Doyle log rule and I am guessing the inside diameter is going to be 12" so I am looking at the rule that woodmizer gave me and it says it should yield 40bf per log.  Now from our previous conversations on the beams I am guessing that there is good select wood and there is less quality pieces.  Does the RULE take that lesser piece into account.  I would guess a nice semi straight log which is 14" OD would give me a 10" square cant.  Cut into 10" x 1" x 10' pieces I should be able to have 75 bf of material assuming that I am going to get 9 pieces 1" thick x 10'.  The RULE says 40 so you have to see why it is confusing when my logic is 10" x 120" x 9 pieces / 144 = 75 sf or BF.

Another question and this is for all but I would like DOC to chime in as well.  I hear alot about oak needing to air dry for a while with the stickers in place before it can go into the kiln.  Now the oak that I am speaking about is white oak (dont know if there is a difference) but there will be red oak as well.  In fact I have the same guy going to bring me some 12"-14" round pin oak.  How long to air dry before it can go into a kiln and once it is in the kiln how many weeks?

Thanks
Rob

[dboyt]

If you are buying logs, the Doyle scale is the most common for hardwoods, but it does underestimate the volume for smaller logs.  If you want to estimate the volume of wood you will get out of a log, use the International 1/4" scale.  In my experience, band saws get about 15% better yield on 1" thick lumber because of the narrower kerf.  Diameter is measured small end, inside the bark.

Using he handy log volume calculator under the "extras" tab of this forum, a 10' long, 12" diameter log yields 40 board feet on the Doyle scale (the scale you would use for buying the log), and 61 board feet on the International scale (which predicts the volume you'd get off the mill, using a saw with a 1/4" kerf).  With a band mill and a 1/8" kerf, you'd get closer to 70 board feet.  This assumes a straight, defect-free log.

[Ron Wenrich]

Logs are scaled inside bark on the small end.  A 14" log scales out to 14", not 12".  The scale is 63, not 40.  A 14" log will cut a 10x10 with no wane, depending on the straightness of the log.  A 12" log will produce a 8½x8½.

The "rules" are on a formula.  Yield will not be the same in all situations.  It depends on sawing patterns and what product you're trying to get.  Sawing for beams will give a different yield than sawing boards.  The cubic volume is the same, but the waste volume is where the difference shows up.  As waste volume increases, board foot recovery decreases.

[ely]

there is no replacement for the training that experience will bring forth... with that being said, you will have  a different opinion when you hit your first nail, regardless of which blade you have, even the fancy nail eater bands will not cut a true line when they have steel stuck on the face of the teeth.

i cant begin to describe the amount of boards that i have cut to build a house with, but i can tell you that when a single person is in charge of sawing the trees down, bucking, milling, drying,planing, installing and finishing the end product, the wood takes on a different meaning to that person. they will have a different idea of what its worth, and a different perspective of grade.

[GAB]

Rob:
Many have chimed in as I'm doing now.  A lot of the advice is dead on.
When hitting a nail, or worse (lag bolts come to mind), in a log or cant the angle the nail is at in relation to the blade path can greatly affect the results or sawing path after you use the blade as a metal detector.  It is possible to affect two boards when such an occasion occurs.  You may be able to get some length out of the two boards involved, however they could be short pieces (for example two 6 foot pieces instead of two 10 footers), if you are willing to use a chop saw and do some salvaging.

I have done a few jobs where I measured all logs after loading them onto the mill and compared the board footage sawed versus the board footage per the International Scale without deducting for crooks, bends, bows, etc. and have had yields of 5 to 35% over the Int. Scale.  If you take a little time and study the log to find the optimum opening spot you should have no problem getting 15% over scale which is referred to as overrun on good logs. The thicker you slabs are the less the overrun.

Concerning your cants; I would consider sawing 15/16" thick provided the cants are dry wood.  If not then I would go for 1" or 1-1/16" thick, because wood shrinks as it dries.  Cupping could also be a problem as wood dries.
Some people suggest using diesel fuel as a blade lubricant.  I love those people that do that, as I get the repeat business if the customer used the wood inside of a home and the wood smells of diesel fuel.

I like the logs loaded onto the mill bed with the small end towards the head.  For one I can see better, I'm more apt to see that my roller is up and not ruin a board by sawing a bottom taper, and I think it saws straighter because of the way branches grow on trees.  When resawing cants you have no idea which end was towards the ground when growing.

I for one would sure like to know how you make out.  What thickness you decided to saw etc.  Wishing you the best.
Gerald

[Brad_S.]

Some people suggest using diesel fuel as a blade lubricant.  I love those people that do that, as I get the repeat business if the customer used the wood inside of a home and the wood smells of diesel fuel.

I call BS unless they used it raw and rough cut.
There is no way it will smell of diesel after going through a planer and getting finished.

[POSTON WIDEHEAD]

Some people suggest using diesel fuel as a blade lubricant.  I love those people that do that, as I get the repeat business if the customer used the wood inside of a home and the wood smells of diesel fuel.

I call BS unless they used it raw and rough cut.
There is no way it will smell of diesel after going through a planer and getting finished.

I agree Brad.

I do not use DIESEL as a lubricant. I use it as a blade cleaner. I lube my blade with water and Cascade dishwashing liquid. During sawing, if build up occurs on my blade, I spray it clean with Diesel and continue sawing with my lube of water and Cascade. There is absolutely NO smell of diesel whatsoever on my lumber.

[tyb525]

I have never heard of board feet being measured as a nominal size. It is measured as the real actual size of the board. So one board foot is in fact one square foot.

One board foot equals 12"x12"x1". Anything less in width or length is not one board foot.

Anything less than 1" thick is calculated as 1". But width and length are calculated to the true measurements.

[mesquite buckeye]

  smiley_argue01


smiley_big-grin2

[GeneWengert-WoodDoc]

If red oak (which includes pin oak) is put into a kiln green, it might take 35 days for 4/4 to get it to 7.0% MC.  If it is put in at 25% MC, it will take around 8 days.  So, a kiln can dry four loads of air dried or one load of green.  Which kiln scenario will make four times more money?

It is indeed possible to dry oak green to 7% MC in a kiln with good controls.  It is just too expensive.

[red oaks lumber]

board foot and sq. foot finished are 2 differant sizes . look in the hardwood book. a 5.5" wide board is still scaling 4 b.f. that is 3.33 sq. ft. if you want to sell sq.ft. at board f.t. rate  you'll lose money every time.
i'm not trying to convince any one i already know the differance 

[GeneWengert-WoodDoc]

For over 100 years, board footage of softwood lumber is measured using nominal size.  It is measured that way today.  A 2x4x8' has 5.33 bf.  Softwood footage is given to two decimals for an individual piece.

Likewise, the instructions for hardwood lumber footage have been around for 100 years.  A 2-1/8" x 3-1/2" x 8' hardwood is 4 bf.  (3-1/2 times 8 divided by 12 equals 2 -- round the answer with no decimals.  Then multiply by 2 for the nominal thickness to get 4 bf.)

[tyb525]

Every definition I've read states 12"x12"x1" is one board foot. It is also one surface square foot. I wouldn't sell lumber by the square foot.

If a board foot is not calculated by the actual width and length of the board, that's news to me

[GeneWengert-WoodDoc]

Check the National Hardwood Lumber Assn rule book for the details, which are exactly as I quoted.  Almost all hardwood lumber sold today uses that NHLA rule book for grading and measuring.  That book has been around with the same basics for 100 years plus.

[Schramm]

Well Doc,
I think that the NHLA should come up with a similar formula to square footage as the explanations seem so hard to understand.  Everything that I have read refers to board feet as 12" x 12" x 1" and that is why I compared it to sq footage and really that is the only reason.  If you measure a surface such as a floor each sq foot is figured 12" x 12" and from the definition of board foot while different is 12"w x 12"L x 1" thick but also states that 13/16" in thickness is considered 1".  Now a figure in square footage is dead on meaning if you measure 10' x 12' that is 120 sf (there is no arguing that) but with wood that does not work the same as the board foot just tells you width x length x thickness and not exactly what it will cover meaning you could never grab a box of hardwood flooring at Home Depot that states it covers 27.5 sf per box as it doesnt assume waste, the installer needs to understand that there is between 10-15% waste that needs to be figured in to that figure.  Same things work with tile and just about everything in construction.  I do get what all of you mean and the answers are very good.  I do like how the answers while different always seem to meet on enough points that it becomes understandable.

Thanks
Rob

[GeneWengert-WoodDoc]

Flooring is not lumber, so all the previous discussion does not apply.

The hardwood rules are easy to use.  In fact, we seldom use the math.  Instead we use a scaling stick, sometimes called a board foot rule.  When placed across the width, the footage will show up in the column for the appropriate lumber length.

Softwood footage is also easy, as there are only a few nominal widths and lengths.  Often softwoods are sold by the number of pieces of a given size and not the footage.

[Schramm]

Oh God another thing to understand, WHAT?  So if it starts as lumber and gets a tongue and groove it then is no longer lumber?  I guess I kinda get that but it is had to believe how long I have been in the construction industry and never knew any of this.  I like square feet better, so simple to do the math.   smiley_sick

[Red Clay Hound]

Every definition I've read states 12"x12"x1" is one board foot. It is also one surface square foot. I wouldn't sell lumber by the square foot.

If a board foot is not calculated by the actual width and length of the board, that's news to me

tyb525, you are arguing with the guy who wrote the book, literally!

[drobertson]

Schramm, It looks to me like you are close to a perfectionist, first by looking at your beautiful work with mirrors, secondly by your method of trying to figure how to maximize these beams, no harm no foul in my opinion.  After reading all the posts, twice, all I can add to this discussion is my opinion, and it is this, however you purchase these reclaimed beams, bdft or piece, you would be well off to figure how many bdft are in them, then saw out the piece parts you need, figure what is useable and calculate your cost to produce them by the bdft, at this point, recalculate the sqft'd of the stock and then price it accordingly if that is how it will be sold.  On logs, I would suggest buying by the doyle scale if possible,(not) around here, and figure as mentioned at least 15% overcut lumber scale compared to the log scale, providing you use good sawing practices,  and yes the log scale includes all the good and bad that in within the log, which none of see until we get to it.  It will take some time and experience to say the least to acquire the skills in sawing that you have displayed in your craft of mirrors,  which are very nice,    david

[tyb525]

My apologies :) if the NHLA book says that's what it is, then that's what it is. I wasn't aware the NHLA considers a  5.5" wide board 6" wide. Thought that was a softwood thing only.

[GeneWengert-WoodDoc]

The NHLA does not consider a 5.5" piece to be 6".  They want the actual width to be multiplied by the nominal length (feet, no inches) and divided by 12, rounded.  This is called the surface measure, SM, and is subsequently used as the basis for grading.

So, for 4/4 lumber, 5.5" x 8' is 4 bf, 9' is 4 bf, 10' is 5 bf, 11' is 5 bf, and 12' is 6 bf the first time and the next piece of that size is 5 bf, 13' is 6 bf, 14' is 6 bf (but a 6.0" piece would be 7 bf), and 15' and 16' are 7 bf. 

[woodandtractors]

WoodDoc-I took hardwood lumber grading course some 30 years ago at UNH-Durham,NH and it did take a lot of time to learn all the rules and exceptions to them.As I recall,it was a 4-week "intensified"course,taught by an older gentleman from Michigan. I was fortunate to go there already knowing board feet and several tricks for figuring same,though I'd never had any experience grading either hard or softwoods. We all were given NHLA rulebooks,a set of 3x5 cards with condensed rules and a Conway-Cleveland 400N board rule. I no longer grade but still find a use for the rule especially on wide pine boards over 12". We learned a lot in a short length of time.
Mike

[WDH]

So, for 4/4 lumber, 5.5" x 8' is 4 bf, 9' is 4 bf, 10' is 5 bf, 11' is 5 bf, and 12' is 6 bf the first time and the next piece of that size is 5 bf, 13' is 6 bf, 14' is 6 bf (but a 6.0" piece would be 7 bf), and 15' and 16' are 7 bf.

I have always thought that this convention was crazy.  It is most likely done just for ease or convenience.  Does not make logical sense at all.  I don't argue that this is the way that BF is measured in the Hardwood Industry, but I still think that it is illogical and crazy.

So, I came up with my own definition of BF for hardwood.  I call it WDH Board Feet. It is simply the width in inches times the length in feet divided by 12.  For 1" lumber, it is the same as the square footage.  The big guys can say that a 5.5" wide by 8' board is 4 board feet and that a 5.5" wide board by 9' is also 4 board feet, but I will not do it.  On the WDH scale, a 5.5" wide by 8' board is 3.7 BF and a 5.5" wide by 9' board is 4.1 BF.

3.7 does not equal 4.1 unless you are using the NEW MATH.  I don't argue with the Industry standard, I just don't choose to use something so illogical.  Then again, I don't have to dealing with woodworkers and my small hardwood sawmilling business.  Free Will is a wonderful thing.

Softwood is just as bad.  A 1.5" by 3.5" piece of wood is not a 2 x 4 except by definition only.  I refuse to go there.  Others can, and many have to because that is how it is done in the Industry, but I don't have to.  Free Will is a wonderful thing.  Just because something has evolved to be done a ceertain way, does not make it right.  It is just how it is done.  In many cases in life, there is No Justice.

I have been in the business for 35 years, but whew, I am glad to finally get that off my chest