Cross-Trade Utilities

Tools in this group

• Unit Converter - Length, area, volume, mass, force, pressure, temperature, energy, power, flow, electrical.
• Material Cost Estimator - Total cost from price per unit and quantity.
• Markup and Margin - Selling price from cost and target.
• Time and Materials - Total billable from hours, rate, and material cost.
• Sales Tax - Tax and total by state.
• Tip Out - Per-person split for crews.
• Loan Payment - Monthly payment, total interest, and 12-month amortization.
• Upgrade ROI / Payback - Simple payback and 10-year NPV at user-supplied discount rate.
• Mileage and Fuel Cost - Gallons, fuel cost, and IRS reimbursement from miles and MPG.
• Overtime Hours - Regular, overtime, and double-time pay breakdown.
• Per-Diem (GSA) - Federal per-diem lodging or M&IE rate by state.
• Geometry Pack - Circle, ellipse (Ramanujan), hexagon, sphere.
• Dilution / Mixing Ratio - Concentrate volume and diluent volume from target strength.
• Slope from Digital Level - Bidirectional between degrees, percent, and inches per foot.
• GPS Distance (Haversine) - Great-circle distance and initial bearing between two coordinates.
• OSHA Trench Sloping - Maximum slope ratio per soil class A/B/C and benching geometry.
• NIOSH Lifting Equation - RWL and Lifting Index per the public NIOSH 1991 multipliers.
• Heat Stress (WBGT and Heat Index) - Heat index, WBGT estimate, and OSHA-style work / rest cycle.
• Wind Chill Exposure - NWS 2001 wind chill formula and frostbite-time exposure curves.
• Ladder Placement Angle - Base distance for the 4:1 rule and pass/fail at 75.5 deg.
• Pulley System Mechanical Advantage - Theoretical and actual MA across fixed/movable/block-and-tackle rigs.
• Ramp Slope (ADA) - Slope ratio, percent, and pass/fail against 1:12 maximum.
• Rainwater Harvesting Yield - Annual gallons from catchment area, rainfall, and collection efficiency.
• Catchment Area for a Target Harvest - The inverse of the rainwater-yield tile: the roof footprint needed to harvest a target volume a year, area = target_gal / (annual_in x 0.6233 x efficiency). Harvesting 11,593 gal a year where 30 in of rain falls, at 0.62 efficiency, needs about 1,000 ft^2; a metal roof at 0.85 efficiency needs only 730 ft^2. Answers 'how much roof do I need' instead of the yield from one roof. The area is the horizontal footprint. A planning estimate; local rainfall, storage, and demand govern.
• Daily Multi-Job Timesheet - Hours per job with overtime split, gross pay, and reimbursable miles.
• Fall Protection Clearance - Required clearance below anchor = free-fall + decel + worker height + harness stretch + safety factor; pass/fail vs actual clearance to next lower level.
• OSHA 1910.95 Noise Dose and TWA - Multi-row workshift dose with the OSHA 5 dB exchange formula, 8-hr TWA, and pass / fail against the 85 dBA action level and 90 dBA PEL.
• Vehicle Load Distribution - Front and rear axle weights with GVWR / GAWR flags.
• Pump Total Dynamic Head (TDH) - Total dynamic head from static lift, static discharge, and Hazen-Williams suction / discharge / fittings friction, with a pump-curve operating point.
• Hydraulic Cylinder Force and Speed - Cylinder force, extend / retract speed, oil per stroke, and cycle time from bore, rod, pressure, and pump flow (NFPA T2.13.7).
• V-Belt Sheave and Drive Sizing - Speed ratio, driven pitch diameter, belt length, service-factor design HP, and a belt-count planning estimate (ANSI/RMA IP-20 / IP-22).
• Belt Power from Tension and Speed - The power a belt actually transmits, from the two tensions and the belt speed: P = (T1 - T2) V / 33000 hp, with V = pi D N / 12 ft/min. The point people miss: only the DIFFERENCE of the tight- and slack-side tensions (the effective tension Te = T1 - T2) does work -- the average tension just clamps the belt for grip and transmits nothing. A 250-to-100 lb drive on a 6 in sheave at 1,750 rpm runs 2,749 ft/min and passes 12.5 HP; a tighter 400-to-250 lb drive keeps the same Te of 150 and the same 12.5 HP while carrying far more total tension into the bearings. Over-tensioning buys wear, not capacity. A design aid; the belt/sheave ratings and wrap angle govern.
• Gear Ratio and RPM Cascade - Per-stage and overall ratio, output RPM, and output torque across up to four gear stages with a per-stage efficiency.
• Rolling Offset - True offset, travel, and run advance for a pipe or conduit rolling offset.
• Wind Speed from Wind Chill and Temperature - The inverse of the wind-chill tile: the wind speed that produces a target or reported wind chill at a known air temperature, w = [ (WC - 35.74 - 0.6215 T) / (0.4275 T - 35.75) ]^(1/0.16) from the NWS 2001 formula. At 5 F air, a -19 F wind chill implies about a 30 mph wind. Valid for T <= 50 F and w >= 3 mph (below 3 mph the ambient temperature governs). A felt-temperature reference; the NWS advisory governs.
• Fitting Take-Out Cut Length - Cut length of pipe between two fittings from center-to-center or face-to-face, with take-out and thread make-up shown.
• Multi-Piece Miter Elbow Layout - Per-cut miter angle, weld count, and cutback for an n-piece lobster-back miter elbow.
• Pipe Wraparound Template Ordinates - Markback ordinate table for wrapping a template to scribe an angled pipe cut.
• Flange Bolt-Up Torque - Target preload and short-form torque (T = K*D*F) per bolt plus the cross/star tightening sequence for a bolted flange joint.
• Center of Gravity from Two Scales - Total weight, CG distance, and the load split from a two-point weigh by moment balance (ASME B30.9 / ITI rigging).
• Insulated Pipe Rack Spacing - Center-to-center spacing, total bundle width, and rack fit for parallel insulated pipe runs from OD, insulation thickness, and clearance (ASTM C585).
• Bolt Circle Layout - Hole coordinates (X, Y) for a circle of N evenly spaced holes from a bolt-circle diameter, start angle, and center, plus the angular spacing and adjacent center-to-center chord (first-principles circle-of-holes trigonometry).
• Decimal to Fraction - Tape-measure math: round a decimal inches value to the nearest 1/8, 1/16, 1/32, or 1/64, reduce the fraction to lowest terms, break it into feet-inches, and report the rounding error (first-principles arithmetic).
• Sine Bar Angle Setup - Precision angle setup: the angle from a gauge-block stack on a sine bar (theta = arcsin(H / L)), or the stack height for a target angle (H = L x sin(theta)), for any roll-center length (first-principles sine-bar trigonometry).
• Thread Pitch and Lead - Thread pitch, lead, and 60-degree sharp-V height for UN/UNC/UNF inch (pitch = 1 / TPI) and ISO metric (pitch in mm) threads: lead = pitch x starts, H = pitch x sqrt(3)/2 (first-principles 60-degree thread geometry).
• Bolt Proof, Yield, and Tensile Load (SAE J429) - The fastener ceiling bolt-torque assumes but never shows: strength acts on the tensile stress area At = 0.7854 x (D - 0.9743/n)^2 (about 15% under the nominal shank, so a nominal-area guess over-predicts), and the grade -- read from the head markings -- sets every number. A 1/2-13 Grade 5 bolt (At 0.1419 in^2) has a 12,060 lb proof load, 17,030 lb tensile, and a 9,045 lb recommended clamp (75% of proof); the identical bolt in Grade 8 jumps to 17,028 lb proof and 12,771 lb clamp. Grade 2: 55/57/74 ksi; Grade 5 / A325: 85/92/120; Grade 8 / A490: 120/130/150. A design aid; the joint design, torque method, and preload requirement govern.
• Three-Wire Thread Measurement - Three-wire measurement over a 60-degree thread: best wire W = 0.57735 x pitch, acceptable wire range, and measurement over three wires M = E + 3W - 0.86603 x pitch from the user-supplied pitch diameter (first-principles thread geometry).
• Pitch Diameter from Three-Wire Measurement - The inverse of the three-wire tile and the way it is actually used on the bench: the pitch diameter from the measurement read over three wires, E = M - 3W + 0.86603 x pitch. A 1/2-13 thread read at M = 0.4900 in over best wires gives E = 0.4234 in. Compare E to the thread-class limits for the fit. First-principles 60-degree geometry.
• Punch / Shear Force - Punching force from the cut perimeter (round, rectangular, or entered directly), material thickness, and shear strength: F = perimeter x T x shear strength, in pounds and US tons, with an estimated stripping force (first-principles shear).
• Punch Capacity: Max Hole or Thickness - The inverse of the punch-force tile: the largest round hole (or the thickest material) a press of a given tonnage can punch, max thickness = F / (pi x D x shear) or max diameter = F / (pi x T x shear), with F = capacity_tons x 2000 lb. A 9.8 ton press punches a 0.5 in hole in 0.25 in of 50 ksi-shear steel - or a half-inch hole in that same quarter-inch plate. Answers 'what can my press punch' instead of the force for one hole. Shear strength ~0.8 x UTS; keep press and tooling margin. First-principles shear; the press and tooling govern.
• Interference Shrink-Fit Temperature - Heating temperature (or chilling temperature) to open an interference fit enough to assemble a hub, bearing, or bushing by hand, from the thermal-growth relation delta_dia = alpha x dia x delta_T (steel alpha 6.5e-6/degF). Sizes only the assembly temperature; a separate Lame contact-pressure check governs the holding capacity.
• Interference Press-Fit Pressure and Holding Force (Lame) - The Lame holding-force check shrink-fit defers: the diametral interference produces a contact pressure p = (E x interference / D) x (Do^2 - D^2)/(2 Do^2), an axial holding force = p x pi x D x length x friction, and a hub bore hoop stress = p x (Do^2 + D^2)/(Do^2 - D^2). A 2 in shaft, 0.002 in interference, 4 in hub, steel, mu 0.12, 3 in engagement grips at 11,250 psi -> 25,447 lb, with 18,750 psi bore stress (below yield); a thin 2.5 in hub drops to 5,400 psi -> 12,215 lb (under half) while the bore stress climbs to 24,600 psi. Too much interference bursts the hub. Same-material solid-shaft model; the materials and assembly method govern.
• Interference for a Target Press-Fit Holding Force - The inverse of the press-fit-pressure tile: the diametral interference that reaches a target axial holding force, i = holding x 2 Do^2 / (E x (Do^2 - D^2) x pi x D x L x mu) -- the holding force is linear in the interference and the interface diameter D cancels. A 25,447 lb target on a 2 in shaft, 4 in steel hub, mu 0.12, 3 in engagement wants 0.0020 in, developing 11,250 psi contact pressure and 18,750 psi hub bore stress. Enter the hub yield to flag a burst. Same-material solid-shaft model; the materials and assembly method govern.
• Rolled Plate Blank Length - Developed flat blank length to roll plate into a cylinder or ring at the neutral axis: L = pi x neutral-diameter, with neutral axis k x T from the inside (D_neutral = OD - 2T(1-k) = ID + 2kT; default k = 0.5 mid-thickness gives pi x (OD - T)) (first-principles arc-length geometry).
• Tolerance Stack-Up: Worst-Case and RSS - Worst-case tolerance = sum of the half-widths; statistical RSS = sqrt(sum of squares), always tighter. Three dims at +/-0.005 -> +/-0.015 worst-case, +/-0.00866 RSS; a 0.020 gap fits 0.005-0.035 (WC) or 0.0113-0.0287 (RSS). The RSS benefit widens as the chain grows. A design aid; the drawing tolerances govern.
• Cone Flat-Pattern Development (Radial Line) - Flat pattern of a right cone: slant L = sqrt(r^2 + h^2), sector radius = L, sweep = 360 r / L. R 6 in, h 8 in -> L 10 in, 216-degree sector; a taller R 6/h 16 cone -> 17.09 in slant, a narrower 126-degree sector. Add seam and bend allowance. A layout aid; verify against a test piece.
• Tank Volume (Dipstick) - Partial liquid volume of a horizontal or vertical cylindrical tank from a depth (dipstick) reading: horizontal uses the circular-segment area R^2 x acos((R-h)/R) - (R-h) x sqrt(2Rh-h^2) times length, vertical uses pi x R^2 x depth, reported in US gallons, liters, and cubic feet with percent full (first-principles geometry, flat ends).
• Linear Interpolation - Read a value between two known points off a chart or table: y = y1 + (x - x1) x (y2 - y1) / (x2 - x1), with the slope and an extrapolation flag when the query falls outside the two points (first-principles linear interpolation for derating, pump-curve, steam, psychrometric, and calibration tables).
• Circular Arc Layout - Radius, arc length, and central angle of a circular arc from a measured chord (span) and rise (sagitta / middle ordinate) at midspan: R = (chord^2/4 + rise^2) / (2 x rise), central angle = 2 x acos((R - rise)/R), arc length = R x angle - the everyday layout question for an arch, curved trim, sheet-metal radius, or road curve (first-principles circle geometry).
• Arc Rise (Sagitta) from Radius and Chord - The inverse of the circular-arc tile: the rise (sagitta / middle ordinate) of an arc from a known radius and chord, rise = R - sqrt(R^2 - (chord/2)^2). A 24 in chord on a 20 in radius rises 4.0 in at midspan; also reports the arc length and central angle. Answers 'how high is the arc' when the radius is set (a curved wall, arch, or road curve). The chord cannot exceed the diameter. First-principles circle geometry.
• Circle Through Three Points - Center and radius of the circle through three measured points on an arc (the circumcircle - the inverse of bolt-circle): center = circumcenter of the triangle, radius = distance from the center to any point, with the diameter and circumference. Recovers a curve's radius from three field points when the chord and midspan rise cannot be measured directly (first-principles coordinate geometry).
• Regular Polygon Miter and Layout - Saw miter and piece sizing to build any N-sided frame (octagon column wrap, hexagon planter, picture frame, segmented ring): each joint is mitered at 180/N degrees off square, the interior angle is (N-2) x 180/N, and the side relates to the across-flats width (s = flats x tan(180/N)) and across-corners diameter (s = corners x sin(180/N)), with perimeter and area (first-principles regular-polygon geometry; square 45, hexagon 30, octagon 22.5).
• Equal Spacing Layout - Evenly space balusters, pickets, studs, shelf pins, or layout marks in a run: N items of width w have N+1 equal gaps of (run - N x w)/(N+1) and a center-to-center pitch of gap + w. Solve for the count from a maximum gap (the smallest N with gap at or below the limit, e.g. the IRC 4-inch-sphere guard rule) or the gap from a desired count, with the mark positions (first-principles layout arithmetic).