Calculated Industries Sheet Metal/HVAC Pro Calc User manual

C
M
Y
CM
MY
CY
CMY
K
PRG4090E-C_COVER.ai 1 11/20/2020 3:05:21 PMPRG4090E-C_COVER.ai 1 11/20/2020 3:05:21 PM

USER’SGUIDE — 1
The custom-designed Sheet Metal/HVAC Pro Calc calculator was
specifically created for sheet metal pro’s to ease the task of
performing mathematics on the job. It includes the most popular
built-in formulas for sheet metal computations, so you’ll save time,
increase accuracy and eliminate errors.
Your Calculator Helps You Solve:
• imensional Math Problems
• Conversions Between Feet-Inch-Fractions, ecimal Feet,
ecimal Inches and Metric
• Problems Involving All Common Fractions – 1/2” to 1/64”
• Area/Volume Calculations
• Arc/Circle/Column/Cone Areas and Volumes
• :M:S
• Scientific Notation, Cubed Root
• Offset Calculations
• Trigonometry
• Law of Cosines
• Fan Laws 1, 2 and 3
• Velocity/Velocity Pressure Conversions
• Right Angle/Rafter Solutions
• Stair Layout (Risers/Treads), and more!
It also includes handy construction math and material estimation
examples — such as right angle/rafter and stair calculations — that
will also help you build faster and more accurately.
INTRODUCTION

2 — SHEET ETAL/HVAC PRO CALC
KEY DEFINITIONS ............................................................................6
BASIC OPERATION KEYS.............................................................6
CONVERT ÇKEY—UNIT CONVERSIONS and
SECOND FUNCTIONS................................................................6
MEMORY and STORAGE FUNCTIONS ........................................7
RECALL ®KEY ..........................................................................8
FEET-INCH-FRACTION and METRIC KEYS .................................8
TRIGONOMETRIC KEYS ...............................................................9
PYTHAGOREAN THEOREM/RIGHT TRIANGLE KEYS..............10
LAW OF COSINES/NON-90 EGREE TRIANGLE KEYS ...........12
OFFSET KEYS..............................................................................13
FAN LAW KEYS ............................................................................14
VELOCITY PRESSURE/FPM KEYS ............................................15
CIRCULAR/ARC FUNCTION KEYS .............................................15
COLUMN/CONE KEY ...................................................................16
HIP/VALLEY and JACK RAFTER KEYS.......................................17
STAIR KEY....................................................................................19
GETTING STARTED........................................................................21
OR ER OF OPERATIONS...........................................................21
USING PARENTHESES ...............................................................22
SETTING FRACTIONAL RESOLUTION.......................................23
Setting Fraction Resolution to Other Than 16ths —
Using the Preference Setting Mode .......................................23
Setting Fixed/Constant Fractional Resolution............................24
ENTERING IMENSIONS............................................................25
Entering Linear imensions.......................................................25
Entering Square/Cubic imensions...........................................25
CONVERSIONS (LINEAR, AREA, VOLUME) ..............................27
Linear Conversions ....................................................................27
Converting Feet-Inch-Fractions to ecimal Feet.......................27
Converting ecimal Feet to Feet-Inch-Fractions.......................27
Converting Fractional Inches to ecimal Inches .......................27
Converting ecimal Inches to Fractional Inches .......................28
Square Conversions ..................................................................28
Cubic Conversions.....................................................................28
PERFORMING BASIC MATH WITH IMENSIONS....................29
Adding imensions ....................................................................29
Subtracting imensions .............................................................29
Multiplying imensions ..............................................................29
TAB E OF CONTENTS

USER’SGUIDE — 3
ividing imensions ..................................................................29
Percentage Calculations ............................................................30
MEMORY OPERATION ................................................................31
EXAMP ES — USING THE SHEET META /HVAC PRO ..............33
BASIC EXAMPLES .......................................................................34
Adding Linear Measurements....................................................34
Converting Feet-Inch-Fractions to ecimal Feet and
Fractions of an Inch................................................................34
Converting Feet-Inches to Meters and Millimeters ....................34
Adding and Subtracting Fractions of an Inch.............................35
Converting Fractions to ecimals..............................................35
Converting ecimals to Fractions..............................................35
Finding Length (of Iron) Required..............................................35
Circumference of a Circle ..........................................................36
Circumference and Area of a Circle...........................................36
Square Area (x2).........................................................................36
Area of a Rectangle ...................................................................36
Area of a Triangle ......................................................................37
Volume of a Rectangular Box ....................................................37
Volume of a Rectangular Container, Converting to
Cubic Meters...........................................................................37
Volume of a Cylinder..................................................................38
Volume of a Cone ......................................................................38
Cubed Function..........................................................................39
Cubed Root Function.................................................................39
Scientific Notation ......................................................................39
TRIGONOMETRIC FUNCTIONS..................................................40
Finding Sine, Cosine, Tangent...................................................41
Finding “Angle A” (ArcSin, ArcCos, ArcTan) ..............................41
Using Trigonometry to Find Unknown Side ...............................41
Using Trigonometry to Find Unknown Angle or Side.................42
Converting Pitch to Angle/Tangent.............................................45
:M:S EXAMPLE ..........................................................................45
Converting egrees:Minutes:Seconds ......................................45
VELOCITY PRESSURE/VELOCITY EXAMPLES.........................46
Converting Velocity Pressure to FPM........................................46
Converting FPM to Velocity Pressure........................................47
OFFSET EXAMPLES....................................................................48
Offset, Basic Example................................................................48
OGEE Offset in Feet-Inch-Fractions..........................................49
OGEE Offset, in Millimeters.......................................................50

4 — SHEET METAL/HVAC PRO CALC
ividing Offset into Multiple egreed Elbows for
Manageable Sections .............................................................51
Change OGEE Offset ................................................................53
LAW OF COSINES EXAMPLES...................................................55
Field Measuring for uctwork Using the Law of Cosines
Introduction .............................................................................55
Non-90 egree Triangle Measurement Using Law of Cosines
and Heron’s Theorem .............................................................56
Using Law of Cosines and Pythagorean Theorem to
Calculate Offset, Length, and Angle.......................................58
Sheet Metal Panels for an Irregular Hip Roof............................59
Inline uct, Single Offset (Computing Offset, Length,
and Angle)...............................................................................60
Inline uct, ouble Offset (Computing Offset, Length,
and Angle)...............................................................................62
Objects at Right Angles .............................................................65
Calculating Angles Between Objects (“Angle Between”)...........69
Calculating Angles Between Objects Example..........................70
FAN LAW EXAMPLES ..................................................................75
Fan Law 1 ..................................................................................75
Fan Law 2 ..................................................................................76
Fan Law 3 ..................................................................................77
ARC/CIRCLE EXAMPLES ............................................................78
Arc Length — Degree and Diameter Known .............................78
Arc Length — Degree and Radius Known.................................78
Using ArcK to Calculate an Arc Length......................................78
Arc Calculations — Arc Length and Diameter Known...............79
Arched/Circular Rake-Walls — Chord Length and Segment
Rise Known.............................................................................80
Arched Windows ........................................................................81
CONCRETE/PAVING ....................................................................82
Squaring-up a Foundation .........................................................82
Volume of a Rectangle...............................................................82
Volume of Columns....................................................................83
RIGHT TRIANGLE and ROOF FRAMING EXAMPLES ...............84
Roof Framing efinitions ...........................................................84
egree of Pitch ..........................................................................86
Percent Grade............................................................................86
Common Rafter Length..............................................................87
Common Rafter Length — Pitch Unknown................................87
Angle and iagonal (Hypotenuse).............................................88

USER’SGUIDE — 5
Rise ............................................................................................88
Rise and iagonal......................................................................88
Sheathing Cut ............................................................................89
Regular Hip/Valley and Jack Rafters .........................................89
Jack Rafters — Using Other Than 16 Inch On-Center
Spacing...................................................................................91
Irregular Hip/Valley and Jack Rafters — Descending, with
On-Center Spacing Maintained ..............................................92
STAIR LAYOUT EXAMPLES ........................................................94
Stair Layout efinitions ..............................................................94
Stairs — iven Only Floor-to-Floor Rise ...................................96
Stairs — iven Only the Run.....................................................98
Stairs — iven Rise and Run....................................................99
Baluster Spacing ......................................................................100
APPENDIX A — TRIGONO ETRY FOR ULAS .........................101
APPENDIX B — AREA/VOLU E FOR ULAS............................102
AREA FORMULAS......................................................................102
SURFACE AREA/VOLUME FORMULAS ...................................103
APPENDIX C — OFFSET FOR ULAS ........................................104
APPENDIX D — LAW OF COSINES/HERON’S THEORE
FOR ULAS ................................................................................105
APPENDIX E — FAN LAW FOR ULAS ......................................106
APPENDIX F — DEFAULT SETTINGS.........................................106
APPENDIX G — PREFERENCE SETTINGS................................107
How to Set Preferences ..............................................................110
Accessing Preference Settings....................................................111
APPENDIX H — CARE INSTRUCTIONS......................................113
APPENDIX I — ACCURACY, AUTO SHUT-OFF, BATTERIES,
ERRORS .....................................................................................114
Accuracy/Errors ...........................................................................114
Auto Shut-Off...............................................................................115
Battery(ies) ..................................................................................115
Replacing the Battery(ies) ...........................................................115
Battery Replacement Instructions ...............................................115
Reset Key ....................................................................................115
REPAIR AND RETURN..................................................................116
WARRANTY ...................................................................................117
INDEX.............................................................................................119

6 — SHEET METAL/HVAC PRO CALC
BASIC OPERATION KEYS
o On/Clear — Turns power on. Pressing once clears the
display. Pressing twice clears all temporary values.
O Turns all power off, clearing all non-permanent registers.
+ – x Arithmetic operation keys.
÷ =
Ç + Percent (%) — Four-function percent. See page 30
for examples.
0–9and •Keys used for entering digits.
BBackspace Key — Used to delete entries one key-
stroke at a time (unlike the ofunction, which
deletes the entire entry).
CONVERT ÇKEY —
UNIT CONVERSIONS and SECOND FUNCTIONS
The Çkey is to convert between measurement units or to access
second functions, listed below:
ÇConvert — Used with the measurement keys to
convert between units or with other keys to access
special functions.
Ç x Clear All — Clears all values, including Memory.
Resets all permanent entries to default values
(except Preference Settings, which are retained).
Note: Use only when necessary, as it deletes all stored values.
XSquares the value in the display. For example, to
Square the value ten, enter 1 0 then press X.
Ç X x3— Cubes the value in the display. For example, to
Cube the value ten, enter 1 0 then press ÇX.
√Square Root Function — Used to find the Square
Root of a non-dimensional or area value
(e.g., 1 0 0 √ = 10).
KEY DEFINITIONS

USER’SGUIDE — 7
Ç √
Ç /
Ç ÷
Ç–
π
Ç π
Ç •
Ç =
Cube Root Function — Used to find the Cube Root
of a non-dimensional or volume value
(e.g., 1000Ç√= 10).
x10 y — Allows entry of an exponent. For example,
8Ç/14is 8 times 10 to the 14th power
(8x1014).
1/x — Finds the reciprocal of a number (e.g., 8
Ç÷= 0.125).
Change (+ / –) Sign — Changes the sign of the dis-
played value to negative or positive.
Pi — Constant = 3.141593
ArcK — Constant = 0.017453. This value is equiva-
lent to the constant of a 1° arc angle for a one-unit
value. The formula for this constant is π ÷ 180.
Degrees: inutes:Seconds — Converts between
:M:S and ecimal egree formats.
Note: Your calculator uses a floating d:m:s format (that is, dis-
plays decimal degrees to the maximum number of decimal points,
for greater accuracy). If you desire rounding to two decimal points
(0.00°), you must set your calculator via Preference Settings (see
page 107).
Access Preference Settings — Used to access
various customizable settings, such as dimensional
answer formats (see Preference Settings on page
107).
MEMORY and STORAGE FUNCTIONS
Your calculator has two types of Memory:
1) basic Memory or Semi-Permanent, Cumulative µ;
2) non-cumulative Storage Registers (M1-M3).
µSemi-Permanent emory — Adds any displayed
number, dimensioned or unitless, to the semi-per-
manent, accumulating Memory. Values can be sub-
tracted from this Memory using Ç µ.® ®
will recall and clear the Memory. Ç ® will swap
the value stored in accumulative Memory with the
value that is currently displayed.

8 — SHEET METAL/HVAC PRO CALC
Ç 1 Storage Register ( 1) — Stores the displayed
value in non-cumulative, permanent Memory (e.g.,
1 0 Ç 1,® 1 = 10). Good for storing a
single value, for future reference.
Note: Non-cumulative means it only accepts one value (does not
add or subtract) and a second entered value will replace the first.
Permanent means the value is stored even after the calculator is
shut off. To delete a stored value, enter a new value or perform a
Clear All (Çx).
Ç 2 Storage Register ( 2) — Same function as Ç
1.See above.
Ç 3 Storage Register ( 3) — Same function as Ç
1.See above.
RECA ®KEY
The ®key is used to recall or review stored values (e.g., ® p
to recall a previously entered pitch value). It is also used in review-
ing stored settings and Memory operation (see below).
® ® Clear + — isplays and clears M+.
® µ Recall + — isplays value stored in M+.
® 1 Recall 1 — Recalls the stored value in M1.
® 2 Recall 2 — Recalls the stored value in M2.
® 3 Recall 3 — Recalls the stored value in M3.
FEET-INCH-FRACTION and METRIC KEYS
The following keys are used for entering units of measure, with ease
and accuracy:
fEnters or converts to Feet. Also used with the i
and /keys for entering Feet-Inch values (e.g., 6
f9i1/2).
Note: Repeated presses after Çtoggle between Feet-Inches and
Decimal Feet (e.g., 6f9i1/2Çf= 6.791667
FEET; press fagain to return to Feet-Inch-Fractions).

USER’SGUIDE — 9
iEnters or converts to Inches. Also used with the /
key for entering fractional inch values (e.g., 9 i
1/2).
Note: Repeated presses after Çtoggle between Fractional
and Decimal Inches (e.g., 9i1/2Çi= 9.5
INCH; press iagain to return to Inch-Fractions).
/Fraction Bar — Used to enter Fractions. Fractions
may be entered as proper (1/2, 1/8, 1/16) or improper
(3/2, 9/8). If the denominator (bottom) is not entered,
the calculator's fractional resolution setting is auto-
matically used (e.g., entering 15/=or +
will display 15/16, based on the default fractional
resolution setting of 16ths.
meters — Enters or converts to Meters.
Ç m illimeters — Enters or converts to Millimeters.
TRIGONOMETRIC KEYS
Tangent Ø = Opposite
Adjacent
Sine Ø = Opposite
Hypotenuse
Cosine Ø = Adjacent
Hypotenuse

10 — SHEET ETAL/HVAC PRO CALC
Your calculator has standard trigonometric keys, in addition to Right
Triangle keys (e.g., R,r,dand p), for advanced Right Triangle
mathematics.
The Sine, Cosine, and Tangent of an angle are defined in relation to
the sides of a Right Triangle.
Using the Çkey with the trigonometric function gives you the
Arcsine, Arccosine and Arctangent – all of which are used to find the
Angle for the Sine, Cosine, or Tangent value entered.
SSine Function — Calculates the Sine of a egree
or undimensioned* value.
Ç S Arcsine (sin -1)— Calculates the angle for the
entered or calculated Sine value.
çCosine Function — Calculates the Cosine of a
egree or undimensioned* value.
Ç ç Arccosine (cos -1)— Calculates the angle for the
entered or calculated Cosine value.
tTangent Function — Calculates the Tangent of a
egree or undimensioned* value.
Ç t Arctangent (tan -1)— Calculates the angle for the
entered or calculated Tangent value.
*Note: Cannot use on dimensioned values.
PYTHAGOREAN THEOREM / RIGHT TRIANG E KEYS

USER’SGUIDE — 11
Using the Pythagorean Theorem, the top row of keys on your Sheet
Metal/HVAC Pro Calc provides instant solutions in dimensional format
to Right Triangle problems for sheet metal problems and roof framing.
The Right Triangle is calculated simply by entering two of four variables:
1) x (Run)
2) y (Rise)
3) r ( iagonal, or Hypotenuse); or
4) θ (Theta/Pitch).
RRun — Enters or calculates “x,” or the Run or hori-
zontal leg (base) of a Right Triangle.
rRise — Enters or calculates “y,” or the Rise or verti-
cal leg (height) of a Right Triangle.
dHypotenuse or Diagonal (for Roof Framing) —
Enters or calculates the Hypotenuse or diagonal leg
of a Right Triangle. Typical applications in construc-
tion/framing are “Squaring-up” slabs or finding
Common rafter lengths. Additional presses of the d
key will also display Plumb and Level cut angles in
degrees.
Note: The Common rafter calculation is the “point-to-point” length
and does not include the overhang or ridge adjustment.
pTheta — Enters or calculates the Pitch (slope) of a
roof (or Right Triangle). Pitch is the amount of “Rise”
over 12 Inches of “Run.” Pitch may be entered as:
• a imension: 9 i p
• an Angle or egrees: 3 0 p
• a Percentage (percent grade): 7 5 Ç + p
Once a Pitch in one of the above formats is entered,
consecutive presses of pwill convert to the remain-
ing pitch formats listed above (e.g., Pitch in Inches
will convert to Pitch egrees, Percent Grade and
Pitch Ratio/Slope).
Note: An entered (vs. calculated) Pitch is a permanent entry. This
means that it will remain stored even after you turn the calculator
off. To change the Pitch, simply enter a new Pitch value.
In contrast, a calculated Pitch value is not permanently stored.
This means that the calculator will return to the Pitch value you
last entered when you press otwice.

12 — SHEET ETAL/HVAC PRO CALC
AW OF COSINES / NON-90 DEGREE TRIANG E KEYS
Ç 9 Law of Cosines — These keys are used for non-90
degree triangle mathematics and are incorporated
with Right Triangle mathematics (using “Measured”
non-90 degree and “Calculated” Right Triangles),
particularly, for finding the dimensional relationship
of distance and alignment between two or more
objects. The overall purpose of these calculations is
to develop the duct and/or fittings required to fill a
space.
These keys calculate the opposite angles A, B, and
C given entry of Side a, b, and c using the Law of
Cosines (see Storage Registers a, b, and c below)
and triangle area using Heron’s Theorem. They also
enable the computation of Right Triangle lengths “x,”
“y,” “r” and Theta, for determining Offset, Length,
and Angle.
Press Result
1 Angle A
2 Angle B
3 Angle C
4 Area (using formula for Heron’s Theorem)
5 Redisplays entered Side a
6 Redisplays entered Side b
7 Redisplays entered Side c
Ç 4 Storage Register “a” — Enters Side “a” of a
Measured Triangle (e.g., if Side “a” is five feet, enter
5 f Ç 4).
Ç 5 Storage Register “b” — Enters Side “b” of a
Measured Triangle.
Ç 6 Storage Register “c” — Enters Side “c” of a
Measured Triangle.

USER’SGUIDE — 13
Right Triangle Functions:
RLength of Unknown Side — Calculates Side “x” of
unknown Right Triangle.
rLength of Unknown Side — Enters Side “y” of
unknown Right Triangle.
dHypotenuse — Enters “c” of Measured Triangle as
“r” of unknown Right Triangle, for final determination
of “x” and “y.”
pTheta — Finds unknown angle for determination of
“x” and “y.”
OFFSET KEYS
Ç ( Offset — Calculates offset measurements, including
the Centerline Radius, Wrapper Length/Stretch-out,
Heel Radius, Throat Radius and Theta, given entry
of “x” (actual length), “y” (offset), and “a” (“end a”)
into the keys below:
Press Result
1 Centerline Radius (CR)
2 Wrapper Length/Stretch-out (WL)
3 Heel Radius
4 Throat Radius
5 Theta (THET)
6 Redisplays entered “x” (Actual Length)
7 Redisplays entered “y” (Offset)
8 Redisplays entered “a” (Storage
Register “a” or End “a”)
RActual Length — Enters the actual length “x” for
offset calculations.
rOffset Length — Enters the offset “y.”
Ç 4 Storage Register “a” — Enters length of “end a”
for offset calculations.

14 — SHEET ETAL/HVAC PRO CALC
FAN AW KEYS
Your calculator also has built-in formulas and keys that calculate Fan
Laws 1, 2 and 3, for air flow calculations. Each of these formulas
requires the entry of three variables in order to solve the fourth.
Ç R Fan Law 1 — Calculates the missing variable (e.g.,
“a-new” or “b-new” for CFM new or RPM new) for
Fan Law 1, given the three known variables into the
applicable Storage Registers (see below). See
page 75 for examples.
Ç r Fan Law 2 — Calculates the missing variable (e.g.,
“a-new” or “b-new” for CFM new or SP new) for Fan
Law 2, given the three known variables into the
applicable Storage Registers (see below). See
page 76 for examples.
Ç d Fan Law 3 — Calculates the missing variable (e.g.,
“a-new” or “b-new” for CFM new or BHP new) for
Fan Law 3, given the three known variables into the
applicable Storage Registers (see below). See
page 77 for examples.
Storage Registers Used For Fan aws:
Ç 4 Storage Register “a” — Enters “a-old” or current
“a” value.
Ç 7 Storage Register “a-new” — Enters “a-new” or
new “a” value.
Ç 5 Storage Register “b” — Enters “b-old” or current
“b” value.
Ç 8 Storage Register “b-new” — Enters “b-new” or
new “b” value.

USER’SGUIDE — 15
VE OCITY PRESSURE / FPM KEYS
Ç 0 VP ß© FP — Converts entry to Velocity (Feet per
Minute - FPM), Velocity Pressure, Metric Velocity
(MPS) and Metric Velocity Pressure (kPA).
Press Result
1Calculates Velocity (FPM) – assumes
entry is Velocity Pressure
2Calculates Velocity Pressure – assumes
entry is Velocity (FPM)
3Calculates Metric Velocity (MPS) –
assumes entry is kPA
4Calculates Metric Velocity Pressure
(kPA) – assumes entry is MPS
See page 46 for examples.
CIRCU AR / ARC FUNCTION KEYS
The Circle key helps you quickly solve Circular Area, Volume or Arc
problems.
CCircle — isplays and calculates the following val-
ues, given an entered Circle iameter* or Radius:
• iameter
• Circumference
• Circle Area
*To enter a Diameter (e.g., ten feet), press 1 0 f C. To
enter a radius, see below.
Ç p Segment Radius — Enters or calculates the Circle
Radius (e.g., 5 f Ç p). Used to calculate
iameter, Circumference and Circle Area (see
above).
Ç C Arc Length or Degree of Arc — A multi-function
key that enters or calculates Arc Length or egree
of Arc, and further solves for additional Circular/Arc
values, including Arched Rake-Walls (based on the
stored on-center), listed on next page.
(Cont’d)

16 — SHEET ETAL/HVAC PRO CALC
(Cont’d)
If a Circle iameter is entered into the Ckey and
Arc egree (or Arc Length) entered into the Arc
function (Ç C), further presses of Cwill dis-
play and calculate the following:
Press Result
1 Arc Length or egree of Arc
2 Chord Length
3 Segment Area
4 Pie Slice Area
5 Segment Rise
6 Stored On-Center Spacing
7 Length of Arched Wall 1
8 Length of Arched Wall 2
9 Length of Arched Wall 3
(if applicable), etc.*
*Note: The calculator will calculate Arched Rake-Wall stud sizes
with consecutive presses of the Ckey until it reaches the last
stud.
RRun (Chord Length) — Used with ror Ç p to
find the Chord Length or the Radius of a Circular
Segment. If the Segment Rise and Radius have
been entered, this key will display the Chord Length
of the Circular Segment.
rRise — Used with Ror Ç p to find the Rise or
the Radius of a Circular Segment. If the Chord
Length and Radius have been entered, this key will
display the Segment Rise of the Circular Segment.
CO UMN / CONE KEY
The Column and Cone functions help you quickly estimate volume
and surface area of Columns or Cones.
Ç ) Column and Cone — The first and second press of
)following Çcalculate the total volume and
surface area of a Column using the values stored in
Cand r; the third and fourth consecutive press-
es of )calculate the total volume and surface area
of a Cone.

USER’SGUIDE — 17
HIP/VA EY and JACK RAFTER KEYS
Your calculator uses the y(rise), x(run), r(diagonal), θ (pitch), and
o.c. spacing values to calculate Regular (45°) and Irregular (non-45°)
Hip/Valley and Jack rafter lengths (excluding wood thickness, etc.).
When calculating Regular and Irregular Jack rafter lengths, you will
see the letters “JK” (Common Pitch side) or “IJ” (Irregular Pitch side)
and the corresponding Jack number to the left of your calculator dis-
play. This will help you keep track of the descending sizes and which
side the corresponding rafter is based on.
HHip/Valley Rafter — Finds the Regular (45°) or
Irregular (non-45°) Hip/Valley rafter length.
•Regular Hip/Valley Length: After Right
Triangle/Rafter values are entered or calculated
(e.g., Pitch, Rise, Run), pressing Hwill calculate
the length of the Regular Hip/Valley rafter.
•Irregular Hip/Valley Length: If an Irregular Pitch is
entered via Ç H (see next page), pressing
Hwill calculate the Irregular Hip/Valley rafter
length. (An Irregular or “non-standard” roof has two
different Pitches/Slopes.)
(Cont’d)

18 — SHEET ETAL/HVAC PRO CALC
(Cont’d)
• Subsequent presses of the Hkey will also dis-
play Plumb, Level, and Cheek cut angle values in
degrees.
Ç H Irregular Pitch — Enters the Irregular or Secondary
Pitch value used to calculate lengths of the Irregular
Hip/Valley and Jack rafters.
You may enter the Irregular Pitch as:
• a imension: 9 i Ç H
• an Angle: 3 0 Ç H
• a Percentage: 7 5 Ç + Ç H
Note: An entered Irregular Pitch can be recalled by pressing ®
Ç H.
jJack Rafters — Finds the descending Jack rafter
sizes for Regular pitched roofs, based on the stored
on-center spacing and previously entered or calcu-
lated Right Triangle/Rafter values (e.g., Pitch, Rise,
Run).
• The default On-Center spacing is 16 Inches. A new
On-Center spacing may be entered and permanent-
ly stored by entering an Inch value prior to perform-
ing the Jack Rafters function (e.g., 1 2 i
j). The current On-Center spacing value can be
viewed by pressing ® j.
• Repeated presses of the jkey will display all
the rafter sizes (on the regular pitch side) as well as
display the Plumb, Level, and Cheek cut angle val-
ues. Additional presses will display the rafter sizes
on the Irregular Pitch side (if an Irregular Pitch was
entered; see above), or repeat the previously dis-
played values.
Note: You may set your calculator to display the Jack rafter
lengths in either ascending or descending order (see Preference
Settings on page 107).
Note: You may program your calculator to “mate up” the Jack
rafters, rather than using the entered or default on center for both
sides (see Preference Settings on page 107).

USER’SGUIDE — 19
Ç j Irregular Side Jacks — Operates same as j,
but displays the rafter values from the irregular
pitched side first.
STAIR KEY
Your calculator easily calculates stair layout solutions. Given values
for r(Rise) and/or R(Run), your calculator will calculate Riser, Tread,
Stringer and Angle of Incline values simply by pressing the key.
A multi-function key that uses a stored “desired”
Riser height, stored “desired” Tread width, stored
Headroom and Floor Thickness, and entered r
(Rise) and/or R(Run) values to calculate and dis-
play the following:
Press Result
1 Riser Height
2 Number of Risers
3 Riser Overage/Underage
4 Tread Width
5 Number of Treads
6 Tread Overage/Underage
7 Stairwell Opening
8 Stringer Length
9 Angle of Incline*
10 Run (entered or calculated)
11 Rise (entered or calculated)
12 Stored Riser Height
13 Stored Tread Width
14 Stored Headroom Height
15 Stored Floor Thickness
Note: Default values are 7-1/2 Inches for Desired Riser Height
and ten Inches for Desired Tread Width, ten Inches for Floor
Thickness and 6 Feet 8 Inches for Headroom.
Note: It is not possible for the calculator to include the Nose/
Overhang Measurement. Thus, you need to adjust for this meas-
urement per local codes.
*Note: If the inclination angle exceeds the stored Rise and stored
Run ratio by 10%, the yield symbol ( )will light, indicating a
steep incline.