Got the board foot blues! (Help!)

[Rich Engelhardt]

I have no idea why I find board feet so confusing....:confused:

I'm pricing out some cabinet doors.
I have 14 doors I want to make.
I want to use raised panels.
I want to use 3/4" stock.

I want the doors to use 2" rails and stiles.
The total width of each door is 17" - as measured from the outside of each stile.
The total length of each door is 29.75" as measured from the outside of each rail.

I come up with 3.51 board feet for each door for the raised panels for a total of 49.14 BF. (17" wide by 29.75 long = 505.75/144 = 3.51 x 14 doors = 49.14)
I come up with 14.28 board feet for the rails and stiles. ( 17" x 2 (34) plus 29.75 x 2 (69.5) = 93.5" (long) x 2" (wide) =187 X 14 (doors) = 2618/144 = 14.28)

18.1 +38.61 = 52.89 BF plus 30% - 68.75 BF

Is this right?

[Peter Quinn]

Very close to my estimate, the devil is in the yield details. That waste factor can go between 10% and 40%+ IME depending on how the material splits up to yield your parts, etc. But 30% is a good safe average for estimating most species....walnut often approaches the 45% waste depending on spec and quality of input.

I Came up with 52.5BF before waste, that's (18X30/144)*14. Add your waste factor to that.

[Judson Green]

Yep you got it.

I'd figure all my linear inches of a certain width stock (say all your style and rail stock) then divide that out. That way you have the LF of all the stock you need to prep. Figure panel stock just the way you did for the door, but group by multiples.

So you'll need 1309 LI of 2" stock or 109 LF add for waste. I'll also divide that number by the length of board I'm using, if all the rips are able to be from the same length boards. So if 8' long boards you'll need 13.63 rips with out waste figured in.

[Lee Schierer]

I get 2.5 bf for each panel. They will only be about 13.75 x 26.5

The rails and stiles are about 1.3 bf. for each door. Remember the rails will be about 4" shorter than the width for the door.

[George Bokros]

I think you are missing something, if the outside dimension of the doors is 17" x 29.75", that includes the raised panel. I come up with 49.17 bdft. You need to add for the tongues and part of the raised panel that is lost for inset into the stiles and rails, my rail and stile set uses 1/4 tongues so I add 1/2" to the dimensions for what is lost there . Add what you want for waste for the total you will need. I just figure what is the area I need to cover with the doors. My assumption is you are purchasing 4/4 stock and milling to the 3/4" thickness.

We all came out with almost the same quantity of wood but I used a simpler approach rather then figure out the bdft in each component I just use the total area to be covered.

I used this approach when I calculated the stock needed for a vanity front and come out on the money, only a little left over.

[lowell holmes]

I would download this calculator.

http://extension.missouri.edu/scripts/explore/G05506.asp

[Lee Schierer]

I think you are missing something, if the outside dimension of the doors is 17" x 29.75", that includes the raised panel. I come up with 49.17 bdft. You need to add for the tongues and part of the raised panel that is lost for inset into the stiles and rails, my rail and stile set uses 1/4 tongues so I add 1/2" to the dimensions for what is lost there .

If the rails and stiles are 2" wide and you put in a 3/8" deep groove for the panel, then your panel ends up being no more than 17-4+3/8+3/8 = 13.75 maximum wide. The panel height is 29.75-4+3/8+3/8 = 26.5 The area of the door panel is 26.5 x 13.75 = 357.75 square inches. Dividing that by 144 gives you 2.484375 square feet or board feet assuming you start with 1" thick material planed down to 3/4"

Stiles are 29.75 x 2 = 59.5 square inches or .413 board feet. Two stiles per door would be .826 bdft. Rails are 2 x 13.75 = 27.5 square inches or .19 bdft Two rails per door would be about .38 bdft. Total wood would be 2.48 +.826 + .38 = 3.686 bdft not counting waste per door.

For 14 doors you would need at least 51 bdft plus waste.

[Rich Engelhardt]

The rails and stiles are about 1.3 bf. for each door. Remember the rails will be about 4" shorter than the width for the door.
Id have forgotten all about that and made them too long..
Thanks for the heads up.

[Chris Padilla]

Don't forget about messing up and having to cut another one...and then messing that one up. :D

[Bill Orbine]

Don't forget about messing up and having to cut another one...and then messing that one up. :D


You mess up??????? What's your waste factor in that?

[Pat Barry]

I think you realy need to figure out how to optimize this in terms of the actual width boards you will buy. Once you narrow it down to stock sizes that you can make use of its pretty easy to figure linear feet. Board feet is a senseless proposition in my mind.

[Chris Padilla]

You mess up??????? What's your waste factor in that?

Oh, I never mess up, Bill. That was for Rich. :D

[Lee Schierer]

Don't forget about messing up and having to cut another one...and then messing that one up. :D

I never make mistooks...........:D

[Mark W Pugh]

I just figure what is the area I need to cover with the doors. My assumption is you are purchasing 4/4 stock and milling to the 3/4" thickness.

We all came out with almost the same quantity of wood but I used a simpler approach rather then figure out the bdft in each component I just use the total area to be covered.

I used this approach when I calculated the stock needed for a vanity front and come out on the money, only a little left over.

I just used this approach on my very first set of cabinets. The calculation came out well.

[John TenEyck]

I just use L x W to come up with the rough square feet required. For 4/4 stock, a sq. foot = a BF. I always buy at least 25% extra, so an exact calculation isn't required. I focus more on making sure I buy widths that minimize waste than anything else.

John

[John Huds0n]

MaxCut 2

http://www.maxcut.co.za/

I usually need to make a cut list anyways, so I use MaxCut2 (free version) to input all my parts and then just keep adding stock until they all fit. No math involved, and I have a pretty good idea what sizes of rough cut lumber are available to input

[Steve Baumgartner]

Board feet with waste allowance gives you a starting point, but Pat raises a very real issue you will have to deal with at the yard: How much waste will there be if you want 2" x 29.75" stiles but the available boards are 7 3/4" wide and 12' long? Neither of the required dimensions will fit neatly into that board, so there will be both width and length waste! I can't tell you how many times I've had to make a trip back to the yard for another board even though the BF amount was ample!

[Curt Harms]

Don't forget about messing up and having to cut another one...and then messing that one up. :D

And here I thought I had an exclusive on that :o

[George Bokros]

Board feet with waste allowance gives you a starting point, but Pat raises a very real issue you will have to deal with at the yard: How much waste will there be if you want 2" x 29.75" stiles but the available boards are 7 3/4" wide and 12' long? Neither of the required dimensions will fit neatly into that board, so there will be both width and length waste! I can't tell you how many times I've had to make a trip back to the yard for another board even though the BF amount was ample!

Yea this is an additional challenge. I keep in mind my kerf loss on the width and make sure I allow enough extra for fudge factor. End length is a little easier to judge easier since typically (unless you dealing with very short project pieces) you have fewer cuts but is still a challenge. Add in the defect loss you may incur and it gets real cloudy.

[ed vitanovec]

In a perfect world its easy to figure out what amount of lumber you will need. Yes you need to consider board widths and lengths available at the lumber yard. What mistakes that could happen while cutting, routing, assembling and finishing. I would get 75BF to start with and if there is left overs that would be in your favor. Keep us posted as you go along with your project, would help me as well as others when we need to do the same thing.

[Ole Anderson]

And hope you have a fireplace or wood burner to use up all of the 20-40% waste, mostly narrow pieces good for kindling.

[scott vroom]

If the rails/stiles + panels are the same wood, I just use the total door width x height + 40% scrap. For your project I came up with ~50 bf + 40% scrap = 70 bf. It's just a rough estimate...I long ago stopped measuring each piece individually. As others pointed out, the real challenge is selecting boards at the lumber yard that minimize scrap. I'd rather have overage than fire up the old 11-MPG Dodge to drive the 30-40 mi round trip for a few more bf because I underestimated.

[Keith Hankins]

IMO the best way is to draw your parts in sketchup. Name the parts i.e. rails/stiles panel etc. dimension your stock in the drawing. Have the cutlist addin(its free), and simply run your the drawing and it will tell you the estimated bf. Keep in mind your rails & stiles ae QS stock and most likely your raised panels is flatsawn.

However, its a great tool for a quick BF estimate. I do add .3 as waste factor for the oopsies.

I've used this on several pieces where a client wants to make some minor adjustments and I modify the drawing i.e. making a cabinet slightly deeper or a piece taller etc. It quickly gives me as estimate for a project. Then I can quickly estimate material costs and add my labor and an OH factor and can quickly turn an estimate around.

Now I mostly work in cherry, so I look for lots in the 500bf range. I get a great price and it lasts for ever. I'm almost down to the point of restocking again, and have found a compatriot that is interesting in going in together to split a 1000bf buy. Again no question I'll use it, but the price is significantly better.

[Kyle Iwamoto]

I'm with Scott on this one. Take a good guess at the BF total and add that 40% excess for mistakes, waste cuts, not having the perfect board to cut etc etc. Another benefit is buying lots of excess is batch color. If you went back 3 months later, you probably not going to find a close color match on your boards. Even maple varies in color.

Scott, that 11 mpg Dodge. Is it a Power Wagon? If it is, I'm jealous.

[Tom Hogard]

Your panels would not be as large as your doors. 17" wide door with 2 - 2" stiles would be 13" plus 1/2" for tongues = 13.5". Height would be 26.25". That would be 2.46 bf per panel, or 34.44 bf for 14 doors. Using wood as your material, I would be very cautious about estimating to this detail. For example, you didn't allow for kerfs, grain matching, etc., in your calculations.