You don't need to be a mathematician to use a screw size chart (M3–M30). The better moment to look at the numbers is now, while changing your mind is still cheap.
Different providers and institutions at times compute the same thing in different ways. Each step is shown openly, precisely so that you can verify it.
What you're calculating
18 MSG steel = 1.27 mm; 18 AWG aluminium = 1.02 mm — not the same. Screw size chart (M3–M30) turns technical references — thread sizes, pipe diameters, sheet-metal gauge, drill-bit sizes — from scattered tables into one fast converter. Industrial standards live in different systems (metric, imperial, DIN, ANSI, ISO), and a conversion error normally means an incompatible part.
Second: swapping BSP (British) with NPT (US) — different angles (55° vs 60°) don't mate without an adapter. Recalculate after changing one input at a time; this displays which assumption controls the computed value and makes an unexpected answer easier to diagnose. Always cross-verify with a table for the specific pipe type.
The arithmetic behind the result
Industrial standards look dry but they're exactly why tens of thousands of firms in different countries can build compatible parts. Keep the original measurement, invoice, specification or log beside the calculation so that a misplaced decimal point can be found. For 6.0 mm the closest fraction is 15/64" (5.95 mm) — the 0.05 mm gap is negligible for most work, but critical in precision machining. Use when handling international documentation (US spec on a European machine), ordering replacement parts, welding (right electrode for the sheet thickness), plumbing (matching BSP–NPT threads), or machining (drill for M6 tap = 5.0 mm, not 6.0).
Example: a 10 mm drill converts exactly to a fractional inch size. In the US — MSG (Manufacturers' Standard Gauge) for carbon steel, AWG for stainless and aluminium.
How to use it
Mark parts with permanent marker (M6, 1/4"-20) so they don't mix up. Keep the most-used conversion tables on hand in the workshop.
When ordering US parts, invariably request technical documentation with exact mm — don't rely on 'approximately'. Third: sheet-metal gauge for steel vs aluminium are different tables. Classic: confusing NPS with OD (2" NPS ≠ 2" pipe, it's 2.375"). For drill bits: keep a set in mm and in inches.
Which is exactly why the next section is hands-on.
Practical applications
- Currency & format: Singapore dollar (SGD, S$).
- Electrical supply: 230 V / 50 Hz, Type G plug (same as UK).
- Units of measure: Fully metric.
- Local notes: Numbers use SGD, metric units and IRAS defaults where applicable.
- VAT / sales tax: Singapore's GST is 9% (as of 1 Jan 2024). Financial services and residential rentals are exempt; exports zero-rated.
When it's worth using
Typical visitors are users across Singapore's CBD, Jurong and Tampines comparing offers or checking a bill, so the worked examples below use realistic local values rather than abstract numbers. DN 50 ≈ NPS 2, but at larger sizes the mismatch grows. Not exactly.
DN (Diameter Nominal) is European metric; NPS is US imperial.
Mistakes worth dodging
Start by checking the input fields rather than the final number. Screw size chart (M3–M30) applies the right tables for each combination. The values entered here are Metric size. With no marking, quantify with calipers: 6 mm ≈ 1/4"; if it visibly doesn't fit a M6 nut, it's 1/4"-20.
What to keep in mind
This Screw size chart (M3–M30) is tuned to practice in Singapore: amounts are shown in Singapore dollar (SGD, S$), formatted as S$1,234.56, and quantities use fully metric. Every figure above applies to Singapore specifically and is reviewed when the rules change. Singapore's rules are unusually flat and predictable, and Screw size chart (M3–M30) reflects that structure directly.
Where income, tax or contributions are involved, the reference framework is IRAS and CPF (Central Provident Fund) — personal income tax 0–24%, GST 9%.
In short
If the screw size chart (M3–M30) earned its keep today, it will again tomorrow. Keep your inputs honest and the screw size chart (M3–M30) will keep its results honest.
Singapore-specific questions
Is this Screw size chart (M3–M30) valid for Singapore?
Yes. It uses Singapore dollar (SGD, S$) and fully metric, and any tax or contribution reference follows IRAS rules.
Which units and number format are used?
Amounts display as S$1,234.56 and quantities in fully metric — the official convention in Singapore.
Which pension and tax model is assumed?
CPF LIFE payouts from 65. The tax framework is personal income tax 0–24%, GST 9%.