how do you estimate board feet for a project?

[BarryC]

I have a couple projects that I want to build and no idea how to estimate the amount of wood I'm gonna need. Is there a method you guys use to get a good idea how much wood to buy?

I have a major gloat coming on October and will need to build a crib and changing table/dresser.

 

[Badabing]

Hey Barry! Congratulations (early, I know, but still worthy). I have a similar gloat coming in September (my daughter is expecting). I have been commissioned to build a crib out of cherry wood and had the same exact question as you.

So, I did lots of research and came up with a highly accurate method of calculating how many board feet are needed to make a crib.....

I just asked Jeremy (Woodwrangler) how much he used when he made his crib :rotflm:

The answer was about 80 board feet of cherry. So that's what I'm getting :icon_thum

BTW, where did you get your plans and hardware for the crib?

 

[TracyP]

this is the board feet calculator posted in the download links area of this web site. You will need to know the approximate sizes of each piece in your project.

Hope this is what you needed

http://www.ncwoodworker.net/forums/downloads.php?do=file&id=120

Congrats on the upcoming major gloat!

 

[BarryC]

Joe, I haven't bought anything yet but I do like the 3 in 1 plans from Rockler so I will probably buy the plans and the hardware from them.

Tracy, thanks for the link. It looks like I can use it with a good bit of figuring.

 

[TracyP]

Tracy, thanks for the link. It looks like I can use it with a good bit of figuring.

I used it to figure wood needed for a pair of end tables and found it to be quite helpful. It does take a bit of figuring, if your plans have a cut sheet as many do, that makes it nice. You can print the cut sheet and list board feet needed beside each piece, then total up and remember to add some for waste and mistakes. That is how I figured mine.

 

[McRabbet]

Barry,

I go through the plans that I've made for the project or, if it is a magazine or other prepared plan, I look at all of the pieces required for the project. I use a very good (for me, YMMV [see NC WW Lexicon under NC WW Info on top menu bar]) software product called Cutlist Plus that allow the user to enter the type of material in broad terms (plywood, dimensioned lumber, rough lumber) and then in more detailed terms (e.g., under dimensioned lumber, one might enter White Oak, Cherry, Red Oak, etc). You can enter an inventory of stock on hand, from various suppliers and so on. Next, you'll define Project info -- e.g., Baby Crib and the assemblies you'll have with it. Finally, you'll enter the specific boards and quantites you'll need for each assembly -- 4 pcs 4/4 Cherry 32" L x 3-1/4" wide and so on. It will then calculate a complete cutlist and diagrams of each board. And it tallies the amount of material you'll need and layouts for that stock. I find it indespensible for larger projects -- check out their website and go through the examples for more details.

 

[TracyP]

Rob,

That is an awesome looking program, I may purchase it for use on future projects, especially the ones without plans and cut sheets. Which version would you recommend for general woodworking?
thanks

 

[Bas]

No easy way that I'm aware of. I simply add the dimensions for all the rails, stiles, panels, moldings, etc. For material thicker than 1" (which is dimensioned to 3/4"), you'll have to multiply accordingly. Then I determine the Fudge Factor, which depends on
- whether I need long pieces or short pieces (cut-offs can be used for short pieces)
- complexity of the project (chance to mess things up)
- wood quality (knots, twists)
- how visible mismatched lumber will be, if you have to buy extra afterwards (painted poplar - zero problem. bookmatched zebrawood - big problem)
- how stupid I plan to be the day I put it together (it's good to plan ahead)

Generally, the FF is around 30%. So, if I estimate 50bd ft., I'll buy 65. If the wood is at a bargain price, I'll buy more. If it's expensive, I'll buy less.

Projects involving contrasting woods were invented by someone who didn't buy enough in the first place :rolf:

 

[McRabbet]

Rob,

That is an awesome looking program, I may purchase it for use on future projects, especially the ones without plans and cut sheets. Which version would you recommend for general woodworking?
thanks

I have the Silver Edition ($89) and it has worked well for me (the limit of 50 parts has forced me to separate some complex projects, but that's been tolerable). It is a big jump to the Gold Edition at $249 even though there have been times I wish I had it for the Proposal and Pricing features. :XXcompute

 

[BarryC]

Projects involving contrasting woods were invented by someone who didn't buy enough in the first place :rolf:

Thanks Bas! I just blew a Diet Coke bubble out of my nose...

 

[Kicbak]

I've never used plans before so I end up know exactly the wood I need as I design my projects. I start with the general dimensions and start taking measurements of the individual components and break them down further to the type of wood (4/4, ply, etc) need to complete each of the "mini" projects.
I find that if I do the design and drawings on graph paper I know much more about how it should go together. That seems to limit my screw ups...

Wes

 

[Trent Mason]

I just had to do this for the first time.

Just draw out what you want the piece to look like. From there, you just need the exact measurements of each piece. Don't forget to take into account things like joints. For example, if you have a piece that has a tenon on each end, you will want to be sure and add however many more inches for that piece to allow for your tenons. Once you have all of the dimensions for each piece, you use the following formula.

(Total Thickness x Total Width x Total Length)/ 144 = Board feet

That will give you your board feet. Also be sure and pay attention to the dimensions of the wood you are getting. You don't want to get 70 BF of 2x2"s. I doubt that would ever happen, but you never know. If there is a minimum thickness that you're going to need for certain pieces, be sure and get something that thick or more thick if possible. Same for length. I find that it is better to cut a big board into little boards rather than glue up a bunch of little boards to make a big board.

I hope that wasn't a big rambling mess. :BangHead: HTH

Trent :headbang:

 

[DaveO]

All great advice, especially adding in a fudge/whoops/ "oh crap" factor to your calculations. You only can be the judge on how much that should be. But always remember wood doesn't go bad, having a few extra boards sure beats the expense, time and frustration in having to find a few extra as you are nearing the end of a project...BTDT, have the tee-shirt, hat and souvenir mug :cussing:

Dave

 

[BarryC]

(Total Thickness x Total Width x Total Length)/ 144 = Board feet

If I want to build a 6 sided box that 36" wide x 12" tall x 12" deep of 1" thick wood my calculation would be:

6" Thick = 1" for each side?
72" Wide = 12" for each side?
168" Length = 36" x 4 + 12 x 2 for the length of the sides?

I have something very wrong because my numbers above show 504 board feet!

If I convert the inches to feet I get .291 board feet.

What do I have wrong???

I'm still reeling from the diet coke incident....

 

[TracyP]

(Total Thickness x Total Width x Total Length)/ 144 = Board feet

If I want to build a 6 sided box that 36" wide x 12" tall x 12" deep of 1" thick wood my calculation would be:

6" Thick = 1" for each side?
72" Wide = 12" for each side?
168" Length = 36" x 4 + 12 x 2 for the length of the sides?

I have something very wrong because my numbers above show 504 board feet!

If I convert the inches to feet I get .291 board feet.

What do I have wrong???

I'm still reeling from the diet coke incident....

ONE THIRTY SIX X 12=

1X36X12=432/144=3 BF AND SO ON

 

[TracyP]

ONE THIRTY SIX X 12=

1X36X12=432/144=3 BF AND SO ON

168x12x1= 2016/144=14 bf total

where 168 is length, 12 is width (or height in this example) and 1 is thickness

hope I haven't confused you

 

[mshel]

Barry,

1" thick x 12" wide x 168" long is the total dimensional lumber you will need.

1x12x168 = 2016 / 144 = 14 bf. Add 20 - 30 % for hiccups and you get 17 - 18 bf.

Keep in mind, that depending on the species of wood you are buying, the boards may not be 12" wide so you will have to figure that in to the equation.

Mike

(Total Thickness x Total Width x Total Length)/ 144 = Board feet

If I want to build a 6 sided box that 36" wide x 12" tall x 12" deep of 1" thick wood my calculation would be:

6" Thick = 1" for each side?
72" Wide = 12" for each side?
168" Length = 36" x 4 + 12 x 2 for the length of the sides?

I have something very wrong because my numbers above show 504 board feet!

If I convert the inches to feet I get .291 board feet.

What do I have wrong???

I'm still reeling from the diet coke incident....

 

[Bas]

If I want to build a 6 sided box that 36" wide x 12" tall x 12" deep of 1" thick wood my calculation would be:

The 1" thick lumber makes it easy. Basically, with 1" thick material, a board foot is 12" x 12". I'm better with the metric system, but last time I checked, 1 foot = 12".

So, a six sided box (I assume that means four sides, a top and a bottom).
two 12" x 36" (sides) = 2 x 3 sq.ft. = 6 sq.ft.
two 12" x 12" (sides) = 2 x 1 sq.ft = 2 sq.ft.
two 12" x 36" (top and bottom) = 6 sq.ft.

For a total of 14 square feet. Since the material is 1" thick, it's also 14 board feet.

If you went with 8/4 stock -guess what, you'd need 32 board feet

I'm still reeling from the diet coke incident....

Good thing you weren't eating Mentos at the same time :icon_bigg

 

[Trog777]

I usually just WAG it.:dontknow:

 

[Trent Mason]

Barry,

If your question hasn't been answered already, this is what I did the other day. I designed a nightstand. I figured out the measurements of each piece and then made a cut list. Just write out piece by piece what you need. If you need multiple cuts of the same piece, which you would for the box you described, just put (example) "4" or "4x" next to that piece. From there, I just calculated the BF of each piece on my cutlist, if need be, I multiplied by how ever many pieces of each. Then I just added it all together to get the total BF for the piece. I also converted feet into inches when I was calculating this. It just makes it easier so you don't have to bother with all of those fractions or decimals of feet.

HTH

Trent