The free reference for manufacturing engineers.
32 free calculators. 14 standards explained. Practical articles. FAI templates. Built and reviewed by working engineers — for QA, production, design, and tooling teams.
Six reference modules. One mission.
Calculators
32 free interactive calculators for tolerance, GD&T, SPC, surface finish, fits, materials, and machining.
Standards
AS9102, PPAP, ISO 13485, ASME Y14.5, ISO 286, ISO 2768 — explained with examples and Indian context.
GD&T Reference
All 14 GD&T symbols, datums, feature control frames, and rules — with diagrams and worked examples.
Templates
Editable AS9102 forms, PPAP checklists, GD&T quick cards, gauge R&R templates, audit prep guides.
Articles
Deep dives on FAI, GD&T, materials, inspection methods, and audit prep — all by working engineers.
Newsletter
One useful calculator, article, or template every Tuesday. 12,400 engineers subscribed. No spam.
Free interactive tools. No signup.
Tolerance Stack-Up
Worst-case & RSS analysis. Add up to 20 dimensions.
Position Tolerance
True position with bonus tolerance, MMC/LMC modifiers.
Cp / Cpk Calculator
Process capability from sample data. Paste up to 1000 readings.
Surface Finish Converter
Ra ↔ Rz ↔ Rmax ↔ µin ↔ N-grade in one click.
ISO 286 Fits Lookup
Hole-shaft fits — H7/g6, H8/h7, all classes.
Part Weight
Volume × density across 40+ engineering materials.
Gauge R&R
ANOVA method. 3 operators × 10 parts × 3 trials.
Sampling Plan (AQL)
ANSI Z1.4 / ISO 2859 — sample size, accept/reject limits.
Every standard your auditor cares about.
Read what your QA team is reading.
14 min read
How to fill AS9102 Form 3: a real example with a Tata Advanced Systems drawing
The five places Tier-2 suppliers lose audit points, the exact wording inspectors look for, and how to handle "characteristic accountability" without rework.
9 min read
Position tolerance with MMC: the bonus tolerance that saves your scrap rate
A worked example showing how the Maximum Material Condition modifier turns a 12% rejection rate into 1.4% for a hole pattern in a steel bracket.
11 min read
PPAP for Mahindra and Tata Motors — what's actually different from AIAG
Indian Tier-1s have specific PPAP variations from the AIAG manual. Here's what to add (and what you can skip) when submitting to either OEM.
7 min read
CMM measurement uncertainty: how to defend your numbers in an audit
The four sources of CMM uncertainty most QA teams forget to document, and how to write a one-page uncertainty budget that satisfies ISO 17025 reviewers.
6 min read
EN8 vs EN24 vs SAE 1045: choosing carbon steel for shafts and bushings
Hardness, machinability, cost per kg in Indian markets, and which OEMs accept which substitutions. With a comparison chart for procurement teams.
Editable forms. Free downloads.
AS9102 Form 1, 2, 3
Latest Rev C format with formulas pre-filled for characteristic accountability.
PPAP Submission Checklist
All 18 PPAP elements with Indian OEM variations (Tata, Mahindra, Bajaj).
GD&T Symbol Quick Card
Single-page laminate-ready reference. 14 symbols, datum rules, reading order.
Gauge R&R — ANOVA
Pre-formatted for 3 operators × 10 parts × 3 trials. Auto-calculates GRR%.