Bolt Torque Spec Chart
In the workshopTightening specs, dry & lubed
Store name: “Bolt Torque Spec Chart”
Coming soon
Not out yet — but it’s close.
Bolt Torque Spec Chart is the shop torque chart without the ad-swamped web page: every common inch and metric bolt, every grade, dry and lubricated, i
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How do you find the right bolt torque spec?
Printed torque charts compute it as T = K × clamp load × bolt diameter, where the clamp load is 75% of the bolt's proof load — the proof stress (from its SAE grade or ISO class) times the thread's tensile stress area. The nut factor K rolls all the friction into one number: about 0.20 dry, 0.15 oiled, and 0.12 for moly or wax, so the same bolt needs roughly a quarter less torque lubricated than dry. Pick an inch size (1/4-inch to 1-inch, Grade 2/5/8) or a metric size (M6–M24, class 8.8/10.9/12.9) to read the tightening torque in both ft-lb and N·m — these are friction estimates, so a fastener maker's published spec always wins on a critical joint.
System
Grade
1/2-13 UNC · UNC · Ø 0.5000 in · 3 radial lines, 120° apart.
Thread condition (nut factor K)
Plain or zinc-plated steel, no lubricant — the printed-chart default.
Tightening torque · dry
75 ft-lb
102 N·m
Target clamp load
9,046 lbf
75% of proof · proof 85,000 psi · Aₛ 0.1419 in²
Same bolt, by thread condition
Dry
75 ft-lb
102 N·m
Oiled
57 ft-lb
77 N·m
Moly / waxed
45 ft-lb
61 N·m
T = K × clamp load × diameter, with clamp load = 75% of proof load. Same computed engine as the app — stress areas per ASME B1.1 / ISO 898-1, proof stresses per SAE J429 / ISO 898-1.
Estimates only. K is a typical handbook friction value, not a measured one, so real torque varies with plating, lubricant, and surface finish. A fastener or assembly maker's published spec always wins for a critical joint. Torque-to-yield / torque-angle fasteners and stainless are out of scope.
Take it with you
The full Bolt Torque Spec Chart app keeps the whole SAE and metric chart in your pocket — every size and grade dry and oiled, an adjustable nut factor with live clamp load, a reverse wrench lookup that turns a wrench setting into the bolts it fits, and head-marking ID to tell which grade is in your hand — all one-tap and fully offline under the car.
Coming soon to the App Store
What it is
The shop torque chart as an app. Pick a bolt size and grade — inch or metric — and get the recommended tightening torque, dry and lubricated, in ft-lb and N·m. Reverse lookup tells you what your wrench setting suits.
Why we built it
Mechanics look up torque specs constantly, and the go-to sources are ad-swamped web charts squinted at on a greasy phone — or a laminated card that only covers one system. Existing apps mostly hardcode a chart someone copied. This one computes every value from the published standards, so the details the copies miss — like Grade 2's strength drop above 3/4" — come out right.
Want one like this?
Bolt Torque Spec Chart is one of 92. We can build yours.
Every app on the shelf started as one honest problem, scoped small and built native, end to end. That’s exactly how we approach client work — designed, built and shipped, without the bloat.
