Johnson-level-tool-mfg RAS-1 Manuel d'utilisateur

NEW Continuous Scribing Notches–Ideal for Ripping at 3-1/2" and 5-1/2".¡Nuevo!Bordes continuos con muescaspara marcaciones idealespara efect

8FIG. 3 The Common Rafter.Then the run is found by dividing in half the building width. Whenaridgeboardisbeingused,deduct1/2itsthicknessfr

9TABLE AChange Inches to Feet1" = .08' 7" = .58' 2" = .16' 8" = .67' 3" = .25' 9" = .75&apos

10FIG. 4 Common Rafter Layout.length.Forourrafterweget15'7-1/2".Thisistherafterlengthfromthetopcuttotheseatplumbmark(

11FIG. 5 Suggested Eave Construction.

12atailrunof1'9".Inthesame“Common”tableasusedabove,foran8”rise,wend: 1' Run = 1' 2-1/2" 9" Run

13FIG. 6 Top Plumb Cut of a Common Rafter.

14building.Nowlineupthedashedline(abovethe80°incre- mentonthesquare)withtheplumbmark(seeFigure7A&7B). Draw the horizontal se

15as you did in Step 1. You may wish to leave the tails long un-til all the rafters are in place, so that you can mark the ends to a line and then cut

16FIG. 9 View of Hip Rafter Layout.HIP-VAL LENGTH: Use the table on page 47 to obtain the hiporvalleyrafterlength(continuingthe8InchRiseex-

17TAIL OR EAVE LENGTH: Use the same procedure as you did for the common rafter but remember to use the Hip-Valcolumn.Againwehaveinourexamplea

INSIDE BACK COVER IS BLANKThe versatility and durability of Johnson’s“Johnny Square®” came to us fromprofessional master carpenter Johnny Wong,an acco

18andamiterallowance(usinga11/2"actualrafterthick-ness) we get: RAFTER LENGTH = 20' 3-7/8" TAIL LENGTH = 2' 8-7

19used, make another plumb mark on the other side of the raf-terjustoppositeofthebottomplumbmark(seeFigure10).STEP 4. CUTTING HIP RAFTER PAT

20Nowmarkacrosstopofridge(asshown).Thismarkwillbethe center of the two intersecting hips. If a common rafter is to be used, the ridge will

21STEP 3. BOTTOM OR TAIL PLUMB CUT: Measure down the topofthevalleyrafterfromtheSEATPLUMBMARKandmarkthetaillength(inourexample:2&apo

22JACK RAFTERSJACK RAFTER LENGTH: The Jack Rafter Tables are dier-ent than those for the other rafters. The table lists, in the first column, the vary

23 FIG. 14 Top View of Hip Jack Rafter Spacing.

24distance from the edge of the last common rafter to the intersection of the hip and ridge, or the valley and top plate(foravalleyjack).Thismea

25 COMMON RAFTER LENGTH = 15' 7-1/2" SUBTRACT (W – P) FROM TABLE = 1' 2-3/8" FIRST HIP JACK RAFTER LENGTH = 14&apos

26The common scale on the square is used for all jack rafters. Whenever a jack rafter rests against a hip or valley rafter, mark aplumbcut,andthen

27roof. For a pitched roof, use the angle scale and make your marknexttotheanglethatistheresultoftheroofinchriseangle minus the overhang

1The Johnson® Rafter Angle SquareThank you for purchasing the Johnson® Rafter Angle Square. Since 1947 Johnson Level & Tool has been developing so

28STAIR LAYOUT EXAMPLEWith our square, stair layout can be done simply and eciently. The layout can be done without hours of calcula-tions.Basicmat

291.Findtheapproximatenumberofstepswiththefollowing formula: TOTAL RISE (inches) APPROXIMATE NO. OF STEPS = 7" Forexample,let’

30Theidealinchriseis7or8(or30°to35°)butmaybefroma5-inch rise to a 14-inch rise depending on the circumstances. The step rise or run m

31STEP 2. LAYOUT STRINGER: First, find the step incline length(seeFigure18)byusingthefollowingformula:STEP INCLINE = (STEP RISE)2 + (STEP RUN

32Now, draw the bottom plumb line using your inch rise on thecommonscaleofthesquare,exactlyasyoudidforthecommonrafter(seeFigures18and

33Theoutsidestepcornersshouldnowbemarkedo(againseeFigure18).Startingfromthebottomplumbline,mea-sure up along the top edge of the s

34TABLE BChange Decimals to Fractions.06" =1/16" .56" =9/16".13" =1/8" .63" =5/8".19" =3

35FIG. 20 A Rafter Support Structure for Solar Panels.Now find the support rafter rise and run by using the tables somewhat in reverse from the way yo

36support rafter length. To begin with, we find a 2' run having a3'9"length.Thisthenleavesa5"lengthwhichresultsinanap

37FIG. 21 Rafter Layout For A Solar Panel.and the front overhang rafter thickness. The roof run betweenpointsAandBisfoundby: ROOF RIS

2MARKINGEDGETOP CUTS/HIP & VALLEYRAFTER SCALECOMMON RAFTER SCALEDEGREE SCALE/PROTRACTOR“T”-BAR(FOOT)1/4" SCALE(1" TO 3-1/2")PIVOTSC

38From this we can get the overhang rafter length, noting thatweareusing2x6raftersgivingathicknessof1-1/2": ROOF RUN BETWEEN A

39Thepitchedraftertopcutlayout(atpointCinFigure21)isthesameasthesupportrafterbottomcutlayout(atpointA).Forthepitchedrafter

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3TABLE OF CONTENTSTypes of Rafters . . . . . . . . . . . . . . . . . . . . . . . . 4Rafter Measurements . . . . . . .

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4TYPES OF RAFTERSCOMMON RAFTER:Arafterthatrunsperpendicular(90°)from the wall plate to the roof ridge when looking straight down at the roof. W

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64For additional copies of this instruction manual go to www.johnsonlevel.comThe manufacturer of this product is not responsible for any errors or omi

NEW Continuous Scribing Notches–Ideal for Ripping at 3-1/2" and 5-1/2".¡Nuevo!Bordes continuos con muescaspara marcaciones idealespara efect

5FIG. 1 Types of Rafters. All cuts on this roof can be made by using the number 8 (i.e. an 8 inch rise).

6RAFTER MEASUREMENTSThe use of our square for rafter layout is based on two simple and commonbuildingmeasurements:(1)therafterrun,and(2)ther

7FIG. 2 Rafter Runs and Rises for Dierent Style Roofs.