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Sheet Metal Joints by the Numbers
Riveted, clinched, screwed, self-clinching and seamed joints in sheet: strength checks, spacing, threads, seams, galvanic pairs, testing and cost
Design mechanical joints in sheet with numbers: rivet shear, bearing and tear-out, pitch and edge distance, clinches, threads in thin sheet, lock seams, galvanic pairs, testing and cost.
Start readingAbout this book
Most sheet metal products are held together by joints that involve no heat: rivets, clinches, self-clinching nuts and studs, screws and folded seams. They are quick, they keep coatings intact, they join metals that cannot be welded together, and they are easy to get wrong in ways that only show in service. A rivet strong enough on its data sheet can tear out of sheet that is too thin or too close to the edge; a thread tapped in 1.2 mm steel holds far less than the screw it carries; a stainless rivet in an aluminium door can corrode the door around it.
This book works through those joints with numbers. It starts with what each joint in a product must do, then covers how riveted joints fail and how to check them, blind and solid rivets, pitch and edge distance, clinching and self-piercing rivets, self-clinching fasteners, screws and threads in thin sheet, folded lock seams, galvanic corrosion and sealing, and testing and costing joints.
It suits mechanical designers, drafters and fabrication engineers. It assumes basic statics and stress, and some familiarity with sheet metal parts; Sheet Metal Parts by the Numbers covers the folded parts themselves, Brazing and Soldering by the Numbers the joints made with filler metal, and the Library’s resistance welding book the spot weld. This book stays with the mechanical joints.
The running case
Every chapter follows one fictional product. This is an illustration. A fabricator makes EN-700, an outdoor equipment enclosure 700 mm high, 500 mm wide and 250 mm deep. Its body is 1.2 mm galvanised steel, folded and joined; its door is 2.0 mm aluminium sheet on a riveted hinge; inside, a 25 kg equipment plate hangs from two brackets fixed to the back wall. The enclosure is built in batches and travels to site by road.
The product, the fabricator and the numbers are invented; none describes KEVOS® work or a real product. Material strengths and fastener ratings are labelled illustrations: real values come from the material’s certificate and the fastener maker’s published data. Prices are in Australian dollars, excluding GST.
Source limits and professional responsibility
The calculations in this book use standard strength-of-materials methods with stated simplifications, and every calculation was checked by running it. Joint design for structural, lifting, pressure or safety-critical duties is governed by the applicable Australian Standards, the fastener maker’s data and the product’s own requirements, and must be checked by a competent engineer. This book is educational; it does not replace a qualified design check or the testing a real joint requires.
Who this book is for
Mechanical designers, drafters and fabrication engineers who join sheet metal parts with rivets, clinches, inserts, screws or folded seams and need the joints to hold, seal and last.
What you will learn
- Check a riveted sheet joint for rivet shear, bearing, net-section tension and tear-out, and find which governs.
- Set rivet pitch, edge distance and row layout, and know where common rules of thumb come from.
- Choose between blind rivets, clinching, self-piercing rivets, self-clinching fasteners and screws for thin sheet.
- Estimate the strength of threads in thin sheet and of folded lock seams, and when each is adequate.
- Control galvanic corrosion at mixed-metal joints, and test and cost a joint before committing to it.
Inside this book
Chapters
- 01What each joint must doList every joint in a sheet metal product with its load, environment, access and service needs, choose a method from them, and catch spot welds that burnt the coating off 97 cm² of seam.
- 02How a riveted joint failsCheck a riveted sheet joint four ways, rivet shear, bearing, net section and tear-out, find which governs, see how edge distance moves it, and catch a bracket that tore out.
- 03Blind and solid rivetsChoose blind or solid rivets by access, load and sealing, match grip range and hole size to the joint, pick head and material, size a solid rivet's length, and catch hinge rivets with the wrong grip.
- 04Pitch, edge distance and eccentric loadsLay out rivets with sound pitch and edge distance, share an eccentric load as shear and prying tension, combine the two, and catch a layout that raised rivet tension 2.6 times.
- 05Clinching and self-piercing rivetsJoin sheet without holes or heat: how clinches and self-piercing rivets form, what their strength depends on, how to check them in production, and catch a clinch die left set for thicker sheet.
- 06Threads in thin sheetSee why a thread tapped in thin sheet is weak, compare extruded holes, self-clinching nuts and rivet nuts, set a torque below torque-out, and catch nuts that spun in their holes.
- 07Folded lock seamsJoin sheet by folding it: grooved, Pittsburgh, standing and double seams, what loads they carry and how they seal, which way the lock should face, and catch a rain-hood seam grooved too loose to grip.
- 08Galvanic pairs and sealingJudge a mixed-metal joint by galvanic order, wetness and area ratio, isolate and seal it, allow for thermal movement, and catch aluminium rivets corroding in a stainless hinge.
- 09Testing jointsTest sheet joints with coupons and product tests, decide specimen numbers and pass criteria first, read the spread and failure modes, and catch a low result hidden in an average.
- 10The cost of a jointCost a sheet joint as part, hole, setting time, tooling and quality, total a product's joints, compare methods with payback, and catch rivets priced against a tool by part cost alone.
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References and source notes
The manuscript and worked examples are original KEVOS® writing. References inform particular concepts; their authors do not endorse this book. Web references were consulted on 26 October 2026.
- Eugene C. Graham, High School Press, Evansville, Indiana. Shop Problems in Sheet Metal for Secondary Schools, with Notes on Equipment, Materials and Shop Methods (1918). Supplied source, read as a subject map of the sheet metal worker's materials, hand machines for folding, grooving, burring and setting down seams, fluxes and riveting practice. No text, drawings or projects are reproduced; this book's treatment, examples and figures are its own, in SI units and modern practice.
- Standards Australia. AS 4312:2019 Atmospheric corrosivity zones in Australia (2019). Named by number and scope only in Chapter 8, as the Australian guideline for classifying a site's atmospheric corrosivity. No categories or values are quoted from it.