Key takeaways
- Original Uncodemy revision notes in 8 units plus a practice question list.
- Worked examples on shaft diameter under combined loading, a helical spring and ball bearing life.
- Failure theories, fatigue lines and joint strength are high-scoring in most papers.
- Not official university notes. Check your own syllabus and allowed design data book.
- Free download after a short form.
About these Machine Design notes
These are original Uncodemy revision notes for Machine Design, written by the Uncodemy trainer team in a clean handwritten style. They follow the topics found in the common Indian B.Tech Mechanical syllabus. They are not official university notes, not a textbook and not a copy of any university's material. Unit names, order and depth differ between universities (AKTU, state technical universities and autonomous colleges all use their own scheme), so check your own syllabus and tick the units you need before you start.
Machine Design is often split into Design of Machine Elements I and II. The notes cover the common topics of both, so tick the units in your paper.
Each unit has short definitions, key formulas in highlighted boxes, comparison tables, "remember" points and worked examples with the steps shown. A list of commonly asked practice questions closes the notes. These are practice questions based on common syllabus topics, not verified past papers.
What's inside the Machine Design notes
The PDF has 8 units plus a practice question list. Here is what each unit covers, so you can match it with your syllabus.
Unit 1: Design Basics
- Design process: steps of machine design and selection of factor of safety.
- Material properties: strength, ductility, hardness and how they guide material choice.
Unit 2: Theories of Failure
- Static failure theories: maximum principal stress, maximum shear stress and distortion energy.
- Choosing a theory: which theory suits ductile and which suits brittle materials.
Unit 3: Fatigue and Stress Concentration
- S-N curve and endurance limit: fatigue behaviour and correction factors.
- Soderberg, Goodman and Gerber: fluctuating stress design lines and which is safest.
- Stress concentration: notch sensitivity and ways to reduce stress raisers.
Unit 4: Shafts, Keys and Couplings
- Shaft design: combined bending and torsion using equivalent torque and moment.
- Keys: types of keys and shear and crushing checks.
- Couplings: rigid and flexible couplings in short.
Unit 5: Riveted, Welded and Bolted Joints
- Riveted joints: failure modes and joint efficiency.
- Welded joints: butt and fillet welds and eccentric loading.
- Bolted joints: bolt stresses, preload and eccentric loads.
Unit 6: Springs
- Helical springs: Wahl factor, shear stress and deflection.
- Spring terms: spring index, stiffness and springs in series and parallel.
Unit 7: Bearings
- Rolling contact bearings: load-life relation and bearing selection.
- Sliding contact bearings: journal bearings and the basics of lubrication.
Unit 8: Gears, Clutches, Brakes and Power Screws
- Gear design: Lewis equation and gear tooth strength basics.
- Clutches and brakes: uniform pressure and uniform wear theories and brake torque.
- Power screws: torque and efficiency of square threads and self-locking.
How to revise Machine Design
Design answers need a clear sequence: data, assumptions, formula, result and check.
- Write the design steps: for shafts, springs, joints and bearings, list the order of calculations on one card each.
- Learn when to use each theory: maximum shear stress or distortion energy for ductile parts, maximum principal stress for brittle parts.
- Practise with the data book: use the same data book your university allows in the exam.
- Round up to standard sizes: always choose the next standard diameter or bearing and state it.
- Redo the worked examples: the shaft, spring and bearing examples are typical exam questions.
Exam focus: high-weightage Machine Design topics
These topics are common across syllabi:
- Theories of failure and factor of safety.
- Fatigue design with Soderberg or Goodman lines.
- Shaft design under combined bending and torsion.
- Riveted, welded and bolted joint strength, including eccentric loading.
- Helical spring stress and deflection with the Wahl factor.
- Bearing life and selection, clutch and brake torque.
Typical numericals worked in the notes
- Shaft carrying a bending moment of 1 kN m and a torque of 1.5 kN m with an allowable shear stress of 50 MPa: find the diameter.
- Helical spring with load 300 N, mean diameter 40 mm and wire diameter 5 mm: find stress and deflection.
- Ball bearing with dynamic capacity 30 kN, load 5 kN at 1000 rpm: life works out to 3600 hours.
Check answers with the factor of safety calculator, the stress-strain calculator and the gear ratio calculator.
A 7-day revision plan for Machine Design
Use this plan in the week before your exam, after you have studied the subject once in class. Spend about two to three hours a day.
- Day 1: Unit 1 (Design Basics), Unit 2 (Theories of Failure). Read, close the PDF, then write the key formulas and definitions from memory.
- Day 2: Unit 3 (Fatigue and Stress Concentration), Unit 4 (Shafts, Keys and Couplings). Read, close the PDF, then write the key formulas and definitions from memory.
- Day 3: Unit 5 (Riveted, Welded and Bolted Joints), Unit 6 (Springs). Read, close the PDF, then write the key formulas and definitions from memory.
- Day 4: Unit 7 (Bearings). Read, close the PDF, then write the key formulas and definitions from memory.
- Day 5: Unit 8 (Gears, Clutches, Brakes and Power Screws). Read, close the PDF, then write the key formulas and definitions from memory.
- Day 6: redo every worked example in the notes without looking at the solution, then check each step.
- Day 7: attempt the practice question list at the end of the PDF in exam time, then go back to the units where you got stuck.
Who these notes are for
- B.Tech semester exams: third-year Mechanical students preparing for Machine Design or Design of Machine Elements papers.
- GATE ME basics: GATE ME machine design questions often come from failure theories, fatigue, joints, bearings, clutches, brakes and springs. The notes cover basics and standard formulas; for GATE you still need a full question bank and previous papers from the official GATE site.
- Interviews: design and product roles often ask about factor of safety, fatigue, bearing selection and why a shaft fails.
- Diploma and lateral-entry students: the plain language and worked steps make the units easy to follow, but check which topics are in your own scheme.
How to use these notes with your textbook
These notes are short on purpose. They are meant for revision, not for learning Machine Design for the first time. Study each unit once from your class notes, a standard textbook or the matching NPTEL course, and then use the PDF to revise quickly. If a topic in your syllabus is missing from the notes, mark it in your syllabus copy and study it from your textbook. If your teacher uses a different method or notation, follow your teacher in the exam. You can also request notes for another subject through the Uncodemy handwritten notes request page.
Download Machine Design Handwritten Notes PDF
Machine Design Handwritten Notes PDF
The PDF carries the same content as this page in a clean, print-ready layout, so you can read it offline and keep it for revision.
8 pages · 263 KB · PDF · Updated 5 Nov 2026