Engineering Tools

Brass Engineering Tools & Calculators

Six free, instant tools for design engineers and buyers — bar weight, thread specs and tap drills across Metric/UNC/BSP/NPT, ISO 286 limits & fits, insert torque and alloy density. Built by a brass manufacturer, not a generic calculator site.

Brass, copper & aluminium bar weight calculator

Estimate the weight of round, hex or square bar stock by alloy — brass, copper or aluminium. Useful for costing raw material, freight and per-piece yield.

grams / piece
kg / metre
kg total

Densities are nominal; actual mass varies with exact composition and tolerance. Round: π·(d/2)²·L. Hex: (√3/2)·AF²·L. Square: side²·L.

Reference: alloy densities per EN 12164 / EN 12165 nominal values. See materials & alloys library.

Thread specification calculator — Metric · UNC · BSP · NPT

Live thread dimensions across four systems — ISO metric coarse, UNC inch, BSP parallel (G, ISO 228) and NPT taper. Pick a series and size; the table below follows your selection.

major Ø d (mm)
pitch P (mm)
pitch Ø d₂ (mm)
minor Ø (mm)
ThreadPitch / TPIMajor ØPitch ØMinor Ø (ext)Tap drillClearance

Coarse-pitch series per ISO 261. Basic diameters per ISO 724: d₂ = d − 0.6495·P, d₃ = d − 1.2269·P (external), D₁ = d − 1.0825·P (internal). Fine-pitch threads (e.g. M8×1) use different pitches — ask us for the full fine series.

References: ISO 261 / ISO 724 / ISO 965 / ISO 273 (metric), ASME B1.1 (UNC), ISO 228-1 (BSP parallel G), ASME B1.20.1 (NPT). See also our thread standards guide.

Tap-drill calculator — Metric · UNC · BSP · NPT

Select a thread series and size for the recommended tap-drill (~75% engagement for metric/UNC). The table follows your selected series.

tap drill (mm)
tap drill (inch)
pitch / TPI
clearance Ø (mm)
ThreadPitch / TPITap drill (mm)Tap drill (inch)Clearance (close / normal)

Metric/UNC tap-drill ≈ major Ø − pitch (≈75% engagement); use a slightly larger drill in free-machining brass to reduce tap load. BSP G drills are for parallel threads (ISO 228-1). NPT holes should be drilled then reamed with a 1:16 taper reamer before tapping for full thread form.

References: ISO 261 / ISO 724 / ISO 273 (metric), ASME B1.1 & Machinery's Handbook tapping data (UNC), ISO 228-1 (G), ASME B1.20.1 (NPT).

Machining tolerance reference — fits & general tolerances

For turned brass rod and CNC parts. Use the ISO 286 fits table to pick shaft/hole pairs for assemblies, the IT-grade table for the actual tolerance band at a given size, and ISO 2768 for untoleranced dimensions on the drawing.

ISO 286 limits & fits calculator

Type a nominal size and a tolerance class — e.g. 8 + H6 — or a complete fit like H7/g6 to get limit sizes and the fit character. Computed per ISO 286-1:2010 / ISO 286-2:2010 (the current editions, confirmed June 2026).

upper limit (mm)
lower limit (mm)
deviation ES/EI (µm)
tolerance IT (µm)

Covers Ø0–500 mm, grades IT1–IT16, deviation letters D–P / d–p incl. H, h, JS, js (uppercase = hole, lowercase = shaft). Press-fit classes r, s and beyond — ask our engineers.

Common ISO 286 fits (hole-basis, H)

FitTypeCharacterTypical use on turned brass parts
H7/g6ClearanceClose running / slidingSpindles, guided pins, rotating shafts needing fine fit
H7/h6ClearanceLocation / slideSlip-fit locating spigots, parts assembled by hand
H8/f7ClearanceFree runningBushings, bearings with lubrication, looser running fits
H11/c11ClearanceLooseWide clearance, weldments, non-critical assemblies
H7/k6TransitionLight keyingLocated parts needing accuracy but occasional disassembly
H7/n6TransitionTightPress-located parts, light-duty drive without slip
H7/p6InterferencePress / driveInserts, bushes & pins retained by interference
H7/s6InterferenceHeavy drivePermanent press fits, shrink/force assembly

ISO 286 tolerance grades (IT), value in µm

Tolerance band width for a given nominal size. A hole H7 = 0 to +IT7; a shaft h6 = 0 to −IT6. Apply the fundamental deviation for other letters.

Nominal size (mm)IT6IT7IT8IT9IT11
over 3 to 6812183075
over 6 to 10915223690
over 10 to 1811182743110
over 18 to 3013213352130
over 30 to 5016253962160
over 50 to 8019304674190
over 80 to 12022355487220

Worked example: a Ø20 mm H7 bore = 20.000 / 20.021 mm (0 to +21 µm). A Ø20 mm g6 shaft = 19.993 / 19.980 mm (−7 to −20 µm), giving a close-running clearance fit.

ISO 2768-1 general (untoleranced) linear dimensions, ± mm

Applies to dimensions without an individual tolerance. We work to class medium (m) by default; tighter classes available on request.

Nominal length (mm)Fine (f)Medium (m)Coarse (c)Very coarse (v)
0.5 to 3±0.05±0.1±0.2
over 3 to 6±0.05±0.1±0.3±0.5
over 6 to 30±0.1±0.2±0.5±1.0
over 30 to 120±0.15±0.3±0.8±1.5
over 120 to 400±0.2±0.5±1.2±2.5
over 400 to 1000±0.3±0.8±2.0±4.0

Typical turned-brass capability: we routinely hold IT7–IT8 on diameters and ISO 2768-m or finer on lengths; critical features can be held to IT6 / ±0.01 mm with in-process gauging. State the fit or tolerance on your drawing and we quote to it.

References: ISO 286-1:2010 & ISO 286-2:2010 (GPS — code system for tolerances on linear sizes; current editions), ISO 1829 (selection of tolerance zones), ISO 2768-1 (general tolerances — linear & angular), ISO 2768-2 (geometrical). Values cross-checked against Machinery's Handbook. See our tolerances guide.

Threaded brass insert — installation reference

Typical guidance for heat-set and press-in brass inserts in thermoplastics. Values are a starting point — always confirm with pull-out and jack-out testing on your own host material.

ThreadTypical insert OD (mm)Boss hole Ø (mm)Heat-set tip tempTypical seating force
M23.2–3.63.0–3.2200–260 °CLight hand press
M2.53.6–4.03.4–3.6200–260 °CLight hand press
M34.0–4.63.8–4.2220–280 °CLight–medium
M45.6–6.05.4–5.6220–280 °CMedium
M56.4–7.16.2–6.5240–300 °CMedium
M68.0–8.57.8–8.0240–300 °CFirm
M89.5–10.59.3–9.6260–320 °CFirm (press)

Boss hole sizes assume amorphous/semi-crystalline thermoplastics; glass-filled grades may need a larger hole. Heat-set tip temperature is set above the polymer melt point, not the insert. Brassland supplies inserts to DIN 16903, IUTB/IUTC/IUTD and customer-specific profiles.

References: DIN 16903 (threaded inserts for plastics) and published heat-set boss-design guidance. Always validate with pull-out / jack-out testing on your own host material. See our brass inserts range.

Brass & copper alloy density reference

Nominal densities for all 19 alloys in the Brassland materials library. Each links to its full datasheet.

Alloy (EN / UNS)Common nameDensity (g/cm³)Typical use
CW614N / CuZn39Pb3Free-machining brass (machining std.)8.50Precision turned components
CW617N / CuZn40Pb2Hot-working brass8.47Forged & machined fittings
CW602N / CuZn36Pb2AsDZR brass8.52Potable-water fittings
CW607N / CuZn36Pb2AsDZR machining brass8.52Water-side components
CW612N / CuZn39Pb2Machining/forging brass8.50Forged blanks, machined parts
CW625N / CuZn35Pb1.5AlAsLow-lead DZR brass8.50Drinking-water components
CW510L / CuZn42Lead-free brass8.37Low-lead turned parts
CuZn37 / CW508LDeep-drawing brass8.44Cold-formed parts
CuZn40 / CW509LDuplex brass8.39General engineering
CW724R / CuZn21Si3PLead-free silicon brass8.30Drinking-water, RoHS-critical
C36000Free-cutting brass (UNS)8.49High-speed turned parts
C37700Forging brass (UNS)8.44Hot-forged components
C35330DZR brass (UNS)8.47Potable-water fittings
C27450Low-lead brass (UNS)8.52Plumbing & hardware
C46400Naval brass8.41Marine & corrosive duty
C69300 / CuZn21Si3PLead-free silicon brass (UNS)8.30Lead-free programmes
C6802Silicon brass (JIS)8.69Lead-free applications
C11000 (ETP)Electrolytic tough pitch copper8.90Electrical / EV terminals
C14500Tellurium copper8.94High-conductivity machined parts

See the full materials & alloys library for chemistry, mechanical properties and standards equivalents.

References: densities per EN 12164 / EN 12165 / EN 1652 nominal values and ASTM B16 / B124. Cross-checked against supplier mill datasheets.

Frequently asked questions

How do you calculate the weight of a brass bar?
Multiply the cross-sectional area by the length to get the volume, then multiply by the alloy density. For a round bar: weight = π × (diameter/2)² × length × density. Common free-machining brass CW617N has a density of about 8.47 g/cm³.
What is the density of brass?
Most leaded machining brasses are 8.4–8.5 g/cm³ — CW614N about 8.50, CW617N about 8.47, DZR CW602N about 8.52. Lead-free silicon brass CW724R is about 8.30 g/cm³ and pure copper C11000 about 8.90 g/cm³.
How do I read a fit like H7/g6?
The capital letter+number is the hole (H7), the lowercase pair the shaft (g6). Each defines a tolerance band per ISO 286 — H7/g6 at Ø20 gives a hole of 20.000–20.021 mm and a shaft of 19.980–19.993 mm: a guaranteed small clearance for close running. Use the Tolerances tab to compute any size.
What is the difference between BSP and NPT threads?
BSP (G, ISO 228-1) is a parallel 55° thread that seals on a washer or O-ring face — common in Europe and Asia. NPT (ASME B1.20.1) is a tapered 60° thread that seals on the thread flanks with sealant — the North American standard. They are not interchangeable.
What torque should I use to install a brass threaded insert?
Installation and seating torque depends on insert type, host material and thread size. The values in the Brassland reference chart are typical guidance for heat-set and press-in brass inserts in thermoplastics; always validate against your own pull-out and jack-out testing for production parts.

Sources & references

ISO 261 / ISO 965 — metric threads
Thread series & tolerance data; UNC per ASME B1.1, NPT per ASME B1.20.1
ISO 286-1:2010 — tolerances & fits
General tolerances & hole/shaft fits
Copper Development Association
Alloy density & property reference
EN 12164 / EN 12165 — brass rod & stock (CEN)
Density & dimensional basis for bar weights
Brassland — Tolerances & fits
Tolerance reference guide
Brassland — Brass Alloy Guide
Alloy density & composition

Last reviewed: June 2026. Calculator outputs are estimates; verify against the governing standard and your drawing for procurement-critical work.

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