Square feet vs board feet and the Doyle rule question

[Schramm]

Another question:  I have seen the beams in pictures and all the ones that I am getting are 10" square and they are very straight, so if I milled them down to 9.25" x 9.25" and then cut them down to 9" x 1" pieces I should get 9 out of each beam.  The beams are 10' long so my question is this: "Does the Doyle log rule apply to barn beams?"  The reason I ask is at the figures given in that rule a 9" log will only yield 16 board feet at a 10' log.

From my figures I will end out with a 9" x 1" piece, now instead of the log rule using sq footage figures (9" x 120" = 1080 si x 9 pieces = 9720 si /144 = 67.5 sf per beam).  Now I know that in milling it goes by board foot but there really is no difference in size as a square foot is 12"x12" and a board foot is 12"x12"x1" the results are the same.  Am I right or am I missing something as according to the Doyle rule I would end out with 16 sf.

Little confusing for a first timer so an explanation would help.
Thanks
Rob

[dgdrls]

Doyle is one system of computing the volume of a log

you have a true rectangular shape 

you would need to back in the size of the rectangular dimensions
into the smallest log possible to retrieve that shape to compare to Doyle scale.

DGdrls

[Schramm]

I have basically a square log and now I just want to cut it into length, I dont understand how that isnt figured the way I mentioned.  The Doyle rule seems to be for a round log and the interior dimension of the bark still making it a round log.  I get square feet, I sell mirror in it all day long however the board feet if I am not mistaken just refers to the width of 12" and 1" thick buy 12" in length.  I know this stuff takes time to understand but in order for me to do the math on if barm beams calculate into good enough profit potential I have to be able to put the yield or close to the yield into my equation.  That is my problem with logs, while I think that I understand the rule I thought that everything worked off the cant and not off the waste that you cut off to get to the cant or am I again wrong.

[Schramm]

Definition of BF:  A unit of measurement of lumber represented by a board 1 foot long, 12 inches wide, and 1 inch thick or its metric equivalent.  In practice, the board foot calculation for lumber 1 inch or more in thickness is based on its nominal thickness and width and the actual length.  Lumber with a nominal thickness of less than 1 inch is calculated as 1 inch.

Here is a Square Foot:  12" x 12"

It is the same thing, just with a square foot you do not have to worry about the 1" thick but for wood you count that as assumed.  So I guess I do understand and that as long as the blade thickness will not take more then .25" (1/4") in 7 passes on the mill then I can assume on a 10" x 10" log cut to a cant of 9" x 9.25" I will yield 67.5 sf off of a 10' beam.  Math is actually the only strong suit other then sales that I have going for me.  The confusing part is calculating in wear and tear on the machine, cost of blades, cost of fuel and transport, cost of kiln time and also the time to mill and mold into flooring and pick up time.  The sales part of it is easy and now I think that I can figure out profit as long as I am figuring the sq ft correctly but I guess if I depreciate the mill yield by 15% I should be ok.



 

Here is my best guess at this point for the cost to process the beam:

Beam cost (10" x 10" x 10') $25
Cost to Transport $2.50
Cost to unload, set up and remove nails $18
Time to mill and stack $10
Run to the kiln co and cost of drying
Rip saw/ and mold into flooring    $90
Bring Back and stack $2

This is give or take: 60 sf of ready to use 100 year old Heart Pine floor $147.50 or $2.46 per sf unfinished.

This flooring retails for $7.50-$10 per sf.  Not a bad turnaround or a bad savings.

[Schramm]

By the way that is calculated into a 15% loss as the yield would be 8" wide flooring that is 3/4" thick.  Now I could save a little molding the flooring myself but the guy that owns the kiln offered to mill it on a custom machine as well as drying so I just figured in his cost.

Rob

[Mountain State Farm]

Schramm,

You are almost right. You have to count the kerf, (1/8", thickness of blade for every cut). You should get 8 1"x 9"x 10' boards which equals 7.5 bf each, for a total of 60 bf per beam.

Log scales estimate the usable lumber in a log which includes side boards. When milling beams and cants, the calculation is precise. Width x height x length minus kerf. 

Dave.

[Schramm]

Gotcha, well not bad math for a newbie and I still think that I will get 9 as I can just square 2 sides and cut them down I was assuming a loss of 3/4" making it square but these are a strong 10" meaning about 10 1/8" wide.  Even at 8 sections I still will be doing ok but I will figure out what it will take to square it off to get a true figure which I cannot really do until I have the beams here.  In my opinion anytime you can fabricate a product that is not done by all with a profit ratio of 100% of your cost you are doing well but from these figures I would be close to 300% and reclaimed flooring will sell in the city (Chicago) all day long.  Only issue is it can turn into a large investment before a large return, but isnt that true about everything in business?

Rob 8)

[Schramm]

Dave,

Re figuring it you are right on the money, it will be 8 per the math.  The only way I will end out with 9 is in 1 only take 1/4" off 2 sides to square it as I have .875 or 7/8" in blade loss.  That would put it right on 9 but you cannot count on it.  Now what if I made the boards 7/8" thick then mold it to 3/4" flooring as I would really like to yield 9 boards out of each beam.
Rob

[dgdrls]

I trust what i posted made sense??

To get a 10"x10" beam you need a 15" diameter log minimum.
14.14"  diagonal
in Doyle scale at 10 feet that is 76 B.F. 

DGDrls

[Mountain State Farm]

Rob,

If the beams are perfectly straight and square, with no twist or movement of any kind, then I would say yes but that is not likely. Older beams should have little or no shrinkage depending on how they have been stored but I would count on 8 and hope for 9. I don't take the time to be that precise with my manual mill. I shoot for 1" and hit it most of the time but not always.

Dave 

[Schramm]

I trust what i posted made sense??

To get a 10"x10" beam you need a 15" diameter log minimum.
14.14"  diagonal
in Doyle scale at 10 feet that is 76 B.F. 

DGDrls

DGDris,

Gotcha and when you first said it I did not understand what you meant but now I get it.  As you can guess when you spend your entire life dealing in both sq inches and sq ft, the rest of it all is foreign to me.

[Schramm]

Dave,

Talked to Steve with the kiln and he said that if I took them down to 7/8's on the mill I would be just fine as I would still get the 9 that I am shooting for.  While I know what you mean and I totally agree Steve (kiln guy) said 7/8"-1" thick but make them uniform or close to.  He said you planes it to thickness and then runs them through the molder which molds the 3 sides.  Going to be beautiful flooring at 8" wide but when I get the 12" beams I should get some nice 9-10" flooring material.

Thanks for the help in understanding.

Rob

[Magicman]

Since I only custom saw, my situation is a bit different.  I just quoted a price for custom sawing some timbers.  For example, if the rough timbers are 10"X10" and are 20' long, then that figures out to 167 bf.  I will measure the rough timbers to determine my sawing charges, not the lumber produced.  My challenge will be to produce as much usable lumber as possible, which I will do, but internal rot/checks will be his loss, not mine.

[terrifictimbersllc]

Not to be pessimistic but probably not all the boards you cut from the beams will meet your quality standards for finished flooring. You should be able to cull these before they go to the kiln/flooring shop that will save some $$.

[millwright]

If you are going to plane them down to 3/4" you probably want to keep the thickness down a little, you don't want to have to plane off any more than you have to.

[red oaks lumber]

i don't want to shoot you hope down but, i see several things that probably wont happen. dealing in reclaimed lumber you have to figure close to 50% waste, rot, splits,ect.
when dealing with a finished size, board ft and sq ft are 2 differant measures, sq ft is using the actual size (width) bf you use the nominal size.
iv'e sawed and milled to flooring several hundred thousand sq. ft of finished product. if you sawed your lumber to 7/8 thick then wanted me to turn it into floor, the first thing i would tell you is its sawed to thin. working with old grit filled lumber your sawing never stays flat and true,leaving yourself with thick and thin boards.
the prices you see advertised are for finished flooring, back relieved ,t&g ,all defected out, what you buy is what you need to cover the waste has already been removed.
trust me if there was that much money to be made. i would just hire my help and i would over see the operation, instead i'm taking my tired beat up wore out body  out of the wood buisness completly.
walk before you try running.

[Ron Wenrich]

A log and a cant are two different products, so you can't possibly assume one scale is equal to the other.  What you do need is a 14" log to cut a 10x10.  Using 14", you come up with a footage of 63.  That would be a little high to saw a 10x10, since there would also be side lumber.  Log scales are designed to cut 1" boards.  Cutting cants will give you overrun.

Log scales are designed around a formula.   They aren't perfect by any means.  Doyle scale under estimates small logs.  Doyle = (diameter - 4)^2/length/16   Doyle is used for buying many types of logs, especially veneer.  Its why it is widely used in the industry.  Loggers understand the Doyle scale, and can easily move from timber to logs without needing to do a lot of figuring. 

[Schramm]

Not to be pessimistic but probably not all the boards you cut from the beams will meet your quality standards for finished flooring. You should be able to cull these before they go to the kiln/flooring shop that will save some $$.

There is 2 different types of reclaimed flooring that I want to deal with 1 is select (best quality) and then rustic (that will have holes, cracks, checking, staining and so on).  Personally I like rustic better then more then I like the clean material.  But to each there own.

[GeneWengert-WoodDoc]

If you are cutting softwood lumber that has a final size of .75" thick by 9.25" wide (at the time of grading; this is the standard size) and let's assume it is 12' long.  You can get 9 pieces.  Each piece has a nominal size of 1x10, so a 12' long piece has 10 bf.  So, the beam will produce 90 bf.  Note that this includes plenty of wood for saw kerf.  In fact, if you sell the wood rough sawn (which can be quite smooth with a good band saw) and use 1/8" kerf or less, you can get 10 pieces and 100 bf.

As stated, Doyle is an estimate for round logs.  We actually deduct for oval shape, curve, etc.

[Schramm]

i don't want to shoot you hope down but, i see several things that probably wont happen. dealing in reclaimed lumber you have to figure close to 50% waste, rot, splits,ect.
when dealing with a finished size, board ft and sq ft are 2 differant measures, sq ft is using the actual size (width) bf you use the nominal size.
iv'e sawed and milled to flooring several hundred thousand sq. ft of finished product. if you sawed your lumber to 7/8 thick then wanted me to turn it into floor, the first thing i would tell you is its sawed to thin. working with old grit filled lumber your sawing never stays flat and true,leaving yourself with thick and thin boards.
the prices you see advertised are for finished flooring, back relieved ,t&g ,all defected out, what you buy is what you need to cover the waste has already been removed.
trust me if there was that much money to be made. i would just hire my help and i would over see the operation, instead i'm taking my tired beat up wore out body  out of the wood buisness completly.
walk before you try running.

I get what your saying but what I do not understand is are you saying that if I cut 1" on the inward cut when I come out I am going to be thinner?  I dont get it why would that be?  Does the wood cause that?  I dont mean to sound stupid but that really does not make any sence.  Are you saying that you have made 100,000 sf of reclaimed flooring or hardwood flooring?  I have been reserching this for better then a year, have watched the mill that own (Lt10) cut through barn beams and I never saw that happen.  I guess that I can just buy 10 beams to start and see how it goes on the first set of cutting but really that doesnt make any sence to me and doesnt seem possible for the blade to jump around like that.  I was told by WoodMizer "AFTER" I bought my mill (in other words they had nothing to gain) that there are a number of blades (Northwood/Timberwolf) that are COBALT as well as 1 that they sent me (for free I might add) and they said that sometimes when cutting beams you have blade dive but they said that these blades can go through nails (the Norwood one says it will go through a board riddled with nails - that seemed a little questionable).  While I am always questionable about peoples intention when they have something to gain I have never heard going in thick and coming out thin.  Please tell me more as with your experience in flooring I would really like to hear about it more.

[Schramm]

If you are cutting softwood lumber that has a final size of .75" thick by 9.25" wide (at the time of grading; this is the standard size) and let's assume it is 12' long.  You can get 9 pieces.  Each piece has a nominal size of 1x10, so a 12' long piece has 10 bf.  So, the beam will produce 90 bf.  Note that this includes plenty of wood for saw kerf.  In fact, if you sell the wood rough sawn (which can be quite smooth with a good band saw) and use 1/8" kerf or less, you can get 10 pieces and 100 bf.

As stated, Doyle is an estimate for round logs.  We actually deduct for oval shape, curve, etc.

Doc,

That is just about the way I was looking at it.  I read all your articles that we were working in WoodMizer info that they sent me.  I guess there is a lot of ways to look at it and I think that the only way for me to test everything is to just do it and see what I get.  I do want to hear the BAD as well as the GOOD as I have been in business long enough to know all is not GOOD.  I see what you are saying and I guess the best way to handle it is to once again call Steve with the kiln and see what he feels is best since he makes flooring daily but we are in a totally different market.

Thanks for the info, makes good sense.

Rob

[WoodenHead]

I'm with those who say that if you can get 9 pieces from the 10" x 10" timber that is great, but in determining a profitable venture I would go with 8.  Yes you can sell a couple different grades of the material that you cut, but some of it may be totally unusable.  Some of the checks in the beams can run deep and you'll find that some of the pieces that have been cut will simply fall apart.  As others have mentioned there may be some rot.  There's only so far that you can take the rustic thing if you know what I'm saying.   ;)

I would not try to saw it to 7/8"  and plane to 3/4".  As others have mentioned you may end up with some thin and thick spots in your lumber during sawing.  This will show on your finished product as spots that were missed by the planer.  I'm working on 1000 square feet of quarter sawn ash flooring.  All said and done I'll have used almost 1800 board feet of ash to make that happen.  The flooring will be top quality, but there's a surprising amount of waste along the way.

[Red Clay Hound]

i don't want to shoot you hope down but, i see several things that probably wont happen. dealing in reclaimed lumber you have to figure close to 50% waste, rot, splits,ect.
when dealing with a finished size, board ft and sq ft are 2 differant measures, sq ft is using the actual size (width) bf you use the nominal size.
iv'e sawed and milled to flooring several hundred thousand sq. ft of finished product. if you sawed your lumber to 7/8 thick then wanted me to turn it into floor, the first thing i would tell you is its sawed to thin. working with old grit filled lumber your sawing never stays flat and true,leaving yourself with thick and thin boards.
the prices you see advertised are for finished flooring, back relieved ,t&g ,all defected out, what you buy is what you need to cover the waste has already been removed.
trust me if there was that much money to be made. i would just hire my help and i would over see the operation, instead i'm taking my tired beat up wore out body  out of the wood buisness completly.
walk before you try running.

I get what your saying but what I do not understand is are you saying that if I cut 1" on the inward cut when I come out I am going to be thinner?  I dont get it why would that be?  Does the wood cause that?  I dont mean to sound stupid but that really does not make any sence.  Are you saying that you have made 100,000 sf of reclaimed flooring or hardwood flooring?  I have been reserching this for better then a year, have watched the mill that own (Lt10) cut through barn beams and I never saw that happen.  I guess that I can just buy 10 beams to start and see how it goes on the first set of cutting but really that doesnt make any sence to me and doesnt seem possible for the blade to jump around like that.  I was told by WoodMizer "AFTER" I bought my mill (in other words they had nothing to gain) that there are a number of blades (Northwood/Timberwolf) that are COBALT as well as 1 that they sent me (for free I might add) and they said that sometimes when cutting beams you have blade dive but they said that these blades can go through nails (the Norwood one says it will go through a board riddled with nails - that seemed a little questionable).  While I am always questionable about peoples intention when they have something to gain I have never heard going in thick and coming out thin.  Please tell me more as with your experience in flooring I would really like to hear about it more.

If everything is working perfectly then yes all your boards will be exactly 7/8" thick.  However, in the real world stuff happens. If you are setting your board thickness manually, you will have slight variations from board to board.  Also, when your blade starts to get a little dull it may start making wavy cuts or dive when it hits a knot or other defect in the cant.  Cutting reclaimed beams will dull your blades regardless of the type blade you are using.  If you want your finished product to be 3/4" and the blade dives 1/8" then you are left with nothing to plane.  I agree with Red Oaks Lumber.  I think you will find that you need to cut your boards thicker than 7/8" to get 3/4" planed flooring.  One way to find out - saw a couple of beams, plane the boards and see what you get.

On the question of board feet vs. square feet...  If you are working with 1" thick lumber then they are one in the same.  However, a 2x12 that is one foot long will be one square foot on the face, but it contains 2 board feet.

[GeneWengert-WoodDoc]

Consider a 1"x12"x12' softwood lumber piece.  It is 12 bf, but the surface is only 11-1/4" x 12' and it is only 3/4"1 thick.  So, one board foot is not one square foot.

For hardwoods, the thickness is often 1-1/8" x 6" x 12' or 6 bf, but a piece 5-1/2" wide is also 6 bf, as is a piece 6-1/2" wide.  So, again one bf is not one square foot.

[Red Clay Hound]

Doc,  Your explanation of the difference between bd. ft. and square ft. is obviously more concise precise than mine.  I was simplifying (perhaps oversimplifying!) to try to explain that board thickness must be taken into account.  That's why you're the Doc!