Here you can find an assortment of mechanical design tools intended to help reduce the monotony of mechanical engineering. The hope is that these guides and help you located frequently need information and will help streamline your design process.
There are tables, formulas, shortcuts and advice. All these should be taken as aids, but never accepted without your own validation of the mechanical design tools within the context of your own application and your own analysis.
If there are any areas where you need further assistance, please feel free to contact us to recommend a new design tool.
Calculating Shaft Diameter Shafts transmit torque and support loads. Designing a shaft means finding the minimum diameter that can handle the combined bending and torsional stresses with an adequate safety factor. Here’s the practical approach. Pure Torsion (Torque Only) For a solid circular shaft transmitting torque T: Shear stress: τ = 16T / (πd³) Minimum … Read more
Quick Reference: Beam Deflection & Stress These are the formulas you’ll use most often in mechanical and structural design. Memorize the first two (center-loaded simply supported and end-loaded cantilever) — every other case is a variation. Simply Supported Beam Case 1: Center Point Load Parameter Formula Max Deflection (at center) δ = PL³ / 48EI … Read more
Understanding Bolt Preload Bolt preload is the tension (clamping force) induced in a bolt when it’s tightened. This preload is what holds your joint together — not the bolt’s ultimate tensile strength. A properly preloaded joint resists external loads by maintaining clamping force on the parts, preventing slippage and fatigue. Why Preload Matters More Than … Read more
What is Coefficient of Thermal Expansion (CTE)? The Coefficient of Thermal Expansion (CTE) tells you how much a material will expand or contract when its temperature changes. This is critical for assemblies where dissimilar materials are joined, or for parts that experience wide temperature swings. Formula: ΔL = α × L₀ × ΔT ΔL = … Read more
What is Young’s Modulus (Modulus of Elasticity)? Young’s Modulus (or modulus of elasticity) is a measure of a material’s stiffness. It tells you how much a material will deform elastically under a given load. A high Young’s Modulus means a stiff material (like steel); a low value means a flexible material (like rubber). Formula: E … Read more
Standard Dowel Pin Dimensions Dowel pins locate and align parts in assemblies. Unlike bolts (which have clearance), dowel pins are precision ground to tight tolerances and pressed into reamed holes. They’re the backbone of fixture design, mold tooling, and any assembly that needs to come apart and go back together in exactly the same position. … Read more
Standard Key & Keyway Dimensions Square and rectangular keys transmit torque between shafts and hubs (gears, pulleys, couplings). The key size is determined by the shaft diameter — there’s a standard match. Square & Rectangular Key Sizes (ANSI B17.1) Shaft Diameter (in) Key Width (in) Key Height (in) Key Type 5/16 to 7/16 3/32 3/32 … Read more
Set Screw Holding Power & Tightening Torque Set screws hold collars, pulleys, gears, and knobs on shafts. Their holding power depends on the point style, material hardness, and seating torque. Under-torqued set screws are the most common cause of components slipping on shafts. Recommended Tightening Torque Set Screw Size Cup Point Torque (in-lbs) Axial Holding … Read more
Interference Fits for Bearings, Pins & Bushings A press fit (interference fit) is when the shaft is slightly larger than the hole, requiring force to assemble. The interference creates a clamping force between the parts — no fasteners needed. Getting the interference right is critical: too little and the part slips, too much and you … Read more
Reading Weld Symbols Weld symbols on engineering drawings tell the welder exactly what joint to make, where to put it, and how big it should be — without writing paragraphs of notes. The system is defined by AWS A2.4 and it’s more logical than it looks once you understand the structure. The Weld Symbol Structure … Read more