Tinsel Strength of Wood

By: Connor Clements

AbstractThe tinsel strength of wood is how much pressure or weight you can put on the center

part of a horizontal piece of wood, ½ an inch thick, ½ an inch wide, and 20 inches long until it

breaks. To test this I set up some stands in my basement that were 18 inches apart and high off the

ground. I then strung weights on steel wire to see how much weight certain types of wood could

hold. Maple was the strongest at 79 pounds. Cherry was second with 71. Third was Oak at 69

pounds. Pine was forth with 67 pounds. Eastern cedar was fifth with 44.5 pounds and plywood was

sixth with 29 pounds. The weight is figured by the maximum that a piece of that type of wood achieved.

Review of LiteratureAccording to Marcelene Edward’s article, (2006), the strength of plywood depends on many different factors. The

first is how thick and long the piece of plywood is. Thicker means it is stronger and longer means it is weaker. The number of layers also has an important role. If there are more layers, the piece is stronger. If the piece is in a

wet environment, then the glue needs to be waterproof otherwise the layers will just fall apart.To test the tinsel strength of wood I needed to know if a piece was going to be strong or weak. According to Mike

Jackson in his article, (2007), the grain of the wood needs to be parallel to the cut in the wood. This makes the piece of wood break all of it’s fibers when it breaks instead of just splitting between the layers. Another factor is knots. Knots disrupt the grain pattern and leave holes in wood. If there is a whole in the piece of wood and the

grain pattern is altered, it is obviously going to be very weak.The stiffness of a piece of wood will affect the tinsel strength. Tim Lovett’s article, (2004), gave me Hankinson’s Formula. Hankinson’s formula is used to calculate the stiffness of wood. It takes the angel of the grain compared

to the cut to calculate the stiffness of a piece. Obviously a higher stiffness will be stronger.Graham M. Francis’ article, (2008), tells me which types of woods will be stronger than others. Hard woods like oak and maple will be stronger than soft woods like pine. My data backed this up. Maple was the strongest at a maximum of 79 pounds. Cherry was second at a maximum of 71 pounds. Oak was third with 69 pounds. Pine was fourth with a maximum of 67 pounds. Eastern cedar was fifth with a maximum of 44.5. Last was plywood

with a maximum of 29. Oak, maple, and cherry are hardwoods. Pine and eastern cedar are soft woods.

Works CitedEdwards, Marcelene. "Crack Crew Tests Wood's Strength." News Tribune 2006. Print.

Francis, Graham M. Tensile Strength of Wood. Tensile Strength of Wood. 2008. Web. 17 Nov. 2009.Jackson, Mike. "Grading Timber." H2O 2007. Print.

Lovett, Tim. "Wood Strength." Wood Strength. July 2004. Web. 17 Nov. 2009.

Question, Problem Statement, Hypothesis

Project Idea: Which types of woods have a higher tensile strength?

Hypothesis: If a certain type of wood, Oak, is denser, then that type of wood will have a

higher tensile strength than types of wood that are less dense, Eastern Cedar.

Experimental Design

Project Idea: Which types of woods have a higher tensile strength?Hypothesis: If a certain type of wood, Oak, is denser, then that type of wood will have a higher tensile strength

than types of wood that are less dense, Eastern Cedar.Materials list:

3 pieces that are 1.3centimeters thick, 1.3 centimeters wide, and 51 centimeters long of Oak, Maple, Eastern Cedar, Pine, Cherry, Popular, Plywood

A stand that is tall enough to string weights to a piece of wood and is 48 centimeters wideSteel wire

Weights starting at 1 gram and going up in 1 gram incrementsA chart and a pencil to graph the results.

Independent Variables: Oak

MapleEastern Cedar

PineCherryPopularPlywood

Dependent variables: The tinsel strength of the pieces of wood in grams.Constants:

A stand to test the pieces onSteel wire

Weights going up by 1 gram eachThe experiment will take place in one day

Moisture content of the woodSize of the pieces

Air temperature – inside houseTemperature of the wood

Control: Plywood

Procedure: The first thing that you would want to do is build a stand that is 48 centimeters wide and 92

centimeters tall to test your pieces of wood.Next you will want to cut all your wood the exact same size of 1.3 centimeters thick, 1.3 centimeters

wide, and 51 centimeters long.Next you will want to calculate the density of your wood by taking you mass in grams and dividing it

by cubic centimeters.Now you will want to take your steel wire and wrap it around the exact center of the piece of wood.

After that you will want to mark 2.5 centimeters in on each side of your piece of wood.Take that mark and put it on the stand at that mark.

Next you will need to make a graph to record your data on.Now you will take your pieces and test them using 1 gram weights that go up by 1 gram.

Once the piece of wood breaks completely in half you will want to subtract one gram from the weight and that will be the tinsel strength of that piece of wood.

You want to take that weight and record it on your graph.Do this until you have the tinsel strength for all of your pieces of wood.

Test 1 Test 2 Test 3 AverageOak 69 64 69 67 1/3Maple 79 78 79 78 2/3Eastern Cedar 44.5 20 29 31.2Pine 64.5 67 64.5 65 1/3Cherry 69.5 71 70 70 1/5Plywood 20 25.5 29 18 4/5

Step by step procedure from experimental design The first thing that you would want to do is build a stand that is 48 centimeters wide and 92

centimeters tall to test your pieces of wood.Next you will want to cut all your wood the exact same size of 1.3 centimeters thick, 1.3 centimeters

wide, and 51 centimeters long.Next you will want to calculate the density of your wood by taking you mass in grams and dividing it

by cubic centimeters.Now you will want to take your steel wire and wrap it around the exact center of the piece of wood.

After that you will want to mark 2.5 centimeters in on each side of your piece of wood.Take that mark and put it on the stand at that mark.

Next you will need to make a graph to record your data on.Now you will take your pieces and test them using 1 gram weights that go up by 1 gram.

Once the piece of wood breaks completely in half you will want to subtract one gram from the weight and that will be the tinsel strength of that piece of wood.

You want to take that weight and record it on your graph.Do this until you have the tinsel strength for all of your pieces of wood.

Results table, graph• In my experiment, Maple was the winner with an average of 78 and 2/3 pounds until it snapped.

This is partly because the pieces of maple did not have any knots, the grain was parallel to the wood, and there were no cracks or any type of other defects in the wood. The main reason maple won is because of the shape in the pours of the wood. The shape was the best for holding loads in that particular direction.

Test 1 Test 2 Test 3 AverageOak 69 64 69 67 1/3Maple 79 78 79 78 2/3Eastern Cedar 44.5 20 29 31.2Pine 64.5 67 64.5 65.3Cherry 69.5 71 70 70.2Plywood 20 25.5 29 18.8

Tinsel Strength of Wood

0102030405060708090

Oak Maple EasternCedar

Pine Cherry Plywood

Type of Wood

Wei

ght

Test 1

Test 2Test 3

Average

Conclusions and Future Studies • My Hypothesis was disproven because I thought that

oak would be the strongest when the actual winner was maple. Oak came in third behind cherry. The only change I would have made to my experiment is to make the pieces smaller. They took a lot of weight to break and when the weights fell it ruined the carpet in my basement.

Acknowledgments

• I want to thank Mr. Hazelbeck, my shop teacher, for allowing me to get and cut the wood. He also helped me with my research. I would also like to thank Mrs. Richards for helping me through the whole project.

Bibliography

Edwards, Marcelene. "Crack Crew Tests Wood's Strength." News Tribune 2006. Print.

Francis, Graham M. Tensile Strength of Wood. Tensile Strength of Wood. 2008. Web. 17 Nov. 2009.

Jackson, Mike. "Grading Timber." H2O 2007. Print.

Lovett, Tim. "Wood Strength." Wood Strength. July 2004. Web. 17 Nov. 2009.