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Wood Working101Lesson 4Calculating Board Feet

Project PlanningSo far we have learned about the different types of trees and its various parts, how wood is seasoned and processed, as well as understanding some basic characteristics to look for when selecting lumber…you are now ready to to start planning your project.

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Project PlanningAfter determining the project you want to build, the next step is to determine:• What material(s) am I going to use?• How much material will I need?• How much is the project going to

cost?• Plus many more!

Cutting DiagramAfter you have selected an appropriate material for you project, the next step is to figure out how are you going to layout your project components to minimize material waste and cost.

A cutting diagram, as the name suggests, is a diagram that shows how you are going layout all the pieces of your project ito get the most out of your material.

Even though the concept is simple, it does take a fair bit of experience and creativity to layout projects efficiently and accurately.

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Cutting Diagram –Hardwood

Cutting Diagram – Sheet Goods

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Calculating WasteWhen laying your cutting diagram don’t forget to account for material that will be lost during the processing and finishing process. As a general rule of thumb follow these guidelines:• Saw Blade Cut = 1/8” lost• Length: Add 2” – 4” to your finished length• Width: Add ½ - 1” to your finished width• Thickness: Add ¼” - ½” to your finished

thickness

Note: the actual amount material you need to add will vary and depend on the quality of the starting material (i.e. warping and defects).

Bill of MaterialsNow that you have determined how much material you need from your cutting diagram, you next need to calculate how much wood is required and the cost of your project.

A simple and easy way to keep track of your materials and price out your project is using a Bill of Materials Worksheet.

On the Bill of Materials you will provide measurement details for each component from your cutting diagram, which will then be used to calculate the number of board feet required and how much the project is going to cost.

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Bill of Materials Form Woodworking Form - Bill Of Materials

Mr. Ostoforov Revised Sept. 11, 2016 Form - Bill of Materials.docx

Name: Grade: Project: Date:

Part Name of Part

Sizes (in feet) Board Feet

Material Cost

Cost (Bd.Ft. x Cost/Bd.Ft. Item ID # Required Thickness Width Length

Notes, Instructions, Hardware, Special Materials, etc… Subtotal

Tax (12%)

Total Cost

Checked & Approved by: Paid in Full on: Student Initial:

Measuring & DimensionsTips:• When rough measuring keep the

math easy by rounding to nice numbers

• If you find it difficult or tedious to calculate the extra material needed for processing you can multiplyyour total amount of board feet by 150% to get a quick estimate.

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What is a board foot? A board foot is the unit of measure used to determine the amount of wood needed for a project and can be calculating by using the following formula:

Calculating board feet? Example 1: Board dimensions – 1½” Thick x 5” Wide x 34” Long

=1.5”x5”x34”

144=

255in3

144= 1.78Bd.Ft

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Calculating board Feet? Example 2: Board dimensions – 1” Thick x 6” Wide x 6’ Long

=1”x6”x6’

12=

36in3

12= 3.0Bd.Ft

Example 3: 5 Board with the dimensions – 1” Thick x 6” Wide x 6’ Long’

If you have more than one board the same size, instead of calculating the number of board each time, simply multiply by the number of boards

3.0 Bd. Ft x 5 Boards = 15 Bd. Ft

Woodworking Form - Bill Of Materials

Mr. Ostoforov Revised Sept. 11, 2016 Form - Bill of Materials.docx

Name: Grade: Project: Date:

Part Name of Part

Sizes (in feet) Board Feet

Material Cost

Cost (Bd.Ft. x Cost/Bd.Ft. Item ID # Required Thickness Width Length

Notes, Instructions, Hardware, Special Materials, etc… Subtotal

Tax (12%)

Total Cost

Checked & Approved by: Paid in Full on: Student Initial:

A1A2BC1C2C3

2

2

14

42

LegsSides

Top

Drawer L&R

Drawer F&B

Dr. Bottom

2”1”1”

½”½”

½”

2”24”24”

4”4”

12”

30”30”48”

12”10”

10”

Eastern Maple w/ 1” Walnut inlay on top2 sets of drawer sliders w/ chrome handles

D1 2

D2 2

Inlay F&B

Inlay L&R½”

½”

1”

1”

44”

20”

Mr. Ostoforov Old & Wise Table Sept 27, 16

$3.90

$7.75

$7.75

$3.90

$3.90$3.90

$3.90$3.90

1.67

10.0

8.0

0.670.56

0.83

0.31

0.14

$6.50

$39.00

$31.20

$2.62

$2.18$3.24

$2.40

$1.09

$88.23

$10.59

$98.82

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Board Feet Comparison

AssignmentYou are complete a Bill of Materials form using the sample pieces of wood provided. You only need to do 5 samples!

You will need to fill out the form correctly.• The quantity specified (on each piece)• The part name (in this case the type of wood)• Measure the actual board to the nearest 1/8th of an inch• Adjust the measurements to account for processing loss• Calculate the number of board feet (2 decimal places)• Calculate the cost for each piece• Calculate the total cost (including 12% tax)