Engineering Articles
Clear answers to real engineering questions.
In-depth articles on tolerance stackup, bolting, lifting, piping, and more — written to explain the reasoning behind the calculation, not just give you a formula to copy.
Jul 11, 2026
Section Weight Calculator Math: From Profile Area and Density to Mass
Learn how solid, hollow, built-up, custom, and DXF profile areas become kg/m, lb/ft, and total member mass, with formulas, unit checks, and a worked steel RHS example.
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Jun 12, 2026
1D Linear Tolerance Stackup: Will the Parts Fit in the Envelope?
Will the parts always fit in the envelope? Worst-case and RSS methods for 1D chains, with the sign conventions that prevent the most common stackup errors.
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Jun 12, 2026
Datum Shift and Bonus Tolerance: How Much Positional Budget Do You Really Have?
A 0.02 position callout at MMC can really give you 0.05. How stated tolerance, bonus, and datum shift add up - and when not to trust the sum.
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Jun 12, 2026
Press Fit or Clearance Fit? Checking Shaft and Bore Limits the Right Way
Guaranteed press, guaranteed clearance, or could it be either? The four limits that decide every shaft/bore fit - and why coating changes the answer.
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Jun 12, 2026
Minimum Thread Engagement: How Deep Must a Tapped Hole Be?
The bolt should break before the threads strip. How to size tapped-hole engagement from proof load and shear strength instead of rules of thumb.
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Jun 12, 2026
Padeye vs Shackle: The Two Fit Checks Every Lifting Lug Needs
A padeye can pass every stress check and still not accept the shackle. The two geometric fit checks to run before the lift plan goes out.
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May 27, 2026
Bolt Head Pull-Through Check: What It Is and How to Calculate It
A bolt head pull-through failure happens when a clearance hole is large enough — after tolerances, build variation, and coating — for the bolt head or washer to slip straight through under load. This guide explains the failure mode in plain terms, walks through the three dimensions that drive the check, and shows you how to run the calculation using the enggtools.in Bolt Head Check module
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Jun 13, 2026
Bolt Torque and Pretension Calculator: API and Metric Handbook Method Explained
A beginner-friendly but detailed guide to bolt preload, torque, pressure separation, structural shear, utilization, and PDF report checking in the EnggTools bolt torque calculator.
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May 27, 2026
How Clearance Hole to Clearance hole Stackup Works — Rectangular pattern
Learn how hole size, position tolerance, bolt camber, and coating thickness combine in a rectangular bolt pattern — explained with real numbers so you can understand exactly what the calculator is doing and why
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May 26, 2026
How Clearance Hole to Clearance Hole Stackup Works — Circular Pattern
When bolts must pass through holes arranged on a bolt circle, small errors in BCD, angle, and hole size all stack up. This guide walks you through the circular clearance hole stackup from scratch — explaining how BCD and angle tolerances convert into a positional shift, how worst-case and RSS results differ, and what to fix when the stackup fails.
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Jun 03, 2026
Tapped Hole to Clearance Hole Stackup — Circular Pattern
When bolts thread directly into tapped holes on a bolt circle — no nuts — every tiny error stacks: off-position clearance holes, an off-size bolt circle, holes a hair off their angle, and a bolt that tilts as it threads in. This beginner-friendly guide shows exactly how BCD tolerance, angle tolerance, hole EBT, coating, the projection lever-arm effect, and bolt camber combine to decide whether the bolts will assemble — with every formula and two fully worked examples.
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May 31, 2026
Tapped Hole to Clearance Hole Stackup — Rectangular Pattern
A practical guide to tapped rectangular tolerance stackups: what makes a threaded joint different from a clearance one, the five inputs that drive the result, and how the projection (lever-arm) effect and bolt camber feed into worst-case and RSS calculations—followed by a complete worked example.
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May 23, 2026
What Is Tolerance Stackup — and Why It Matters
When every part is within spec yet nothing fits together, tolerance stackup is usually to blame. Understanding it is the difference between a product that works and one that doesn't.
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