## Fractional Equivalents For Decimal Values

Where rafter lengths are determined by multiplying unit lengths by the run, the answer will almost invariably result in a decimal. Such decimal values may be readily translated into fractional forms by means of the accompanying table.

Example: A roof of ⅓ pitch has a common rafter run of 14'; find the length of common rafter.

Answer: 14x14.42"=201.88" or 16.82'. By the table, .82 = 53/64. A carpenter, however, would not care for such accuracy; the nearest 1/16" or even ⅓" would be sufficient.

## Wood And Machine Screw Sizes

The difference between consecutive sizes is .01316".

Frequently the carpenter wishes to know the diameter of hole necessary to receive the shank of a screw of a certain gage. Should a screw gage be accessible, he may readily determine this. Should no gage be at hand, he may determine the size of hole by consult-ing the accompanying table of Wood and Machine Screw Sizes..

Example: What size bit must be selected to bore a hole for a No. 10 screw. By the table, a No. 10 screw is .18944" in diameter. By the table of Fractional Equivalents for Decimal Values it will be seen that a 3/16" bit must be used. The test for gage of screw is always made over the shank just below the head.

## Length And Number Of Wire Nails To The Pound

Nails are sold in quantity by the keg, 100 lbs. of nails, exclusive of the keg. Twenty, 30,40,50 and 60d are" base." Other sizes have certain fixed additions per keg to this base price. For example, the price list adopted by manufacturers in 1896 allows an addition per keg of \$.70 for 2d common, \$.45 for 3d common, etc.

Wire nails are also bought and sold by weight, the size of wire according to the standard wire gage and the length in inches being taken into consideration in specifying the size and in fixing the price per pound.

Common wire nails are thick and have large flat heads. They are used in rough work where strength is desired. Finishing nails are used for fine work such as inside woodwork and cabinet work. Casing nails are somewhat thicker and stronger than finishing nails; they have smaller heads.

 Size, inches.................. ½ ½ ⅝ ¾ ¾ ¾ ⅞ ⅞ 1 Wire Gage, nos............... 20 18 19 19 18 16 18 17 18 Approx. no. brads to lb........ 7500 7200 4267 3556 2758 2600 2364 1781 2069 Size, inches.................. 1 1 1¼ 1¼ 1½ 1½ 1½ 1¾ 1¾ Wire Gage, nos............... 17 16 17 16 16 15 14 15 14 Approx. no. brads to lb....... 1558 1143 1246 913 761 584 500 500 406 Size, inches.................. 2 2 2½ 2½ 3 3 3 ... ... Wire Gage, nos............... 14 13 13 12 14 12 11 ... ... Approx. no. brads to lb....... 350 268 214 164 150 137 105 ... ...

## Strength Of Materials Yellow Pine Posts

 Load in Tons LengthIN FT. Size in inches 4x4 5x5 6x6 7x7 8x8 9x9 8 4 5 6 7 8 9 10 3 4 5 6 7 8 12 2 3 4 5 6 7 14......................... 1 2 3 4 5 6 16......................... ... 1 2 3 4 5 18......................... 1 2 3 4

## Hard Pine Beams And Girders

 Load in Tons LengthIN FT. Size in inches 2x6 3x6 4x6 6x6 8x8 6................................ 1 1½ 2 3 5½ 8................................. ¾ 1 1½ 2½ 5 10................................ ¾ 1 2 4½ 12................................ ½ 1 1½ 3 14................................ . . ½ 1 2½ 16................................ • • a ½ 2 18................................ 1
 STEEL I BEAMS Load in Tons Length in ft. Size in inches 6 8 12 10.... 7 14 18 12.... 6 12 16 14.... 5 10 14 16.... 4 8 12 18.... 2 6 10 20.... 4 8 22.... 2 6 24.... .. 4
 BRICK PIERS Load in Tons HeightIN FT. Size in inches 6x6 6x8 8x8 8x12 12x12 12x16 16x16 6......................... 2 3 4 5 6 7 9 8......................... 1½ 2½ 3½ 4½ 5½ 6 8 10......................... 1 2 3 5 5½ 6 7

## Stresses For Structural Timbers

 Working Unit Stresses Used In Dry Locations Bending Compression Species of Timber Stress in extreme fibreLbs. sq. in. Horizontal shear stressLbs. sq. in. Parallel to grain "ShortColumns" Lbs. sq. in. Perpendicular to grain Lbs. sq. in. *Fir, Douglas - Dense grade............ 1,600 100 1,200 350 Sound grade......... 1,300 85 900 300 Hemlock, eastern......... 1,000 70 700 300 Hemlock, western........... 1,300 75 900 300 Oak....................... 1,400 125 900 400 Pine, eastern white.......... 900 80 700 250 Pine, Norway............... 1,100 85 800 300 *Pine, southern yellow Dense grade.............. 1,600 125 1,209 350 Sound grade......... 1,300 85 900 300 Spruce..................... 900 70 600 200 Tamarack.............. 1,200 95 900 350

* Note: The safe working stresses given in this table are for timbers with defects limited according to the sections on defects in the rules of the Southern Pine Association for Select Structural Material. "Dense" southern yellow pine and "dense" Douglas fir should also conform to the other requirements of this rule. "Sound" southern yellow pine and "sound" Douglas fir require no additional qualifications, whereas the other species should, in addition to being graded for defects, have all pieces of exceptionally low density for the species excluded. •

This table gives working unit stresses for structural timbers used in dry locations, and is compiled in the main from material furnished by the Forest Products Laboratory, Madison, Wis.

## Table Of Brick Wall Contents In Number Of Bricks

 Seven Bricks to Each Sq. Ft. of Wall Surface No. OFSQ FT. OF WALL Thickness 4" 8" 12' 16" 20" 24" 1.................... 7 15 23 30 38 45 2.................... 15 30 45 60 75 90 3.................... 23 45 68 90 113 135 4.................... 30 60 90 120 150 180 5.................... 38 75 113 150 188 225 6.................... 45 90 135 180 225 270 7.................... 53 105 158 210 263 315 8.................... 60 120 180 240 300 360 9.................... 68 135 203 270 338 405 10.................... 75 150 225 300 375 450 20.................... 150 300 450 600 750 900 30.................... 225 450 675 900 1,125 1,350 40.................... 300 600 900 1,200 1,500 1,800 50.................... 375 750 1,125 1,500 1,875 2,250 60.................... 450 900 1,350 1,800 2,250 2,700 70.................... 525 1,050 1,575 2,100 2,625 3,150 80.................... 600 1,200 1,800 2,400 3,000 3,600 90.................... 675 1,350 2,025 2,700 3,375 4,050 100.................... 750 1,500 2,250 3,000 3,750 4,500

Example - Determine the number of bricks in a wall 12"X18'X60'. Solution - The wall contains a surface area of 1,080 sq. ft. By the table

100 sq. ft. contains 2,250 bricks, then 1,000 sq. ft. will contain 22,500 bricks.

80 sq. ft. will contain, by the table, 1,800 bricks, making a total of 24,300 bricks.