Best Screw & Bolt Assortment Sets for Mechanical Assemblies (2026)

We ranked kits by mechanical fit (thread sizes and head types), included complementary hardware (nuts/washers), material/grade, user ratings, and overall value for workshop applications

This roundup covers screw and bolt assortment sets suited for mechanical assemblies, focusing on metric flange bolts, hex-socket machine screws, and multi-size bolt-and-nut kits with washers. Picks were chosen for mechanical fit (thread sizes and flange/socket types), included hardware variety, and value across common workshop needs

Top Picks

1
Kadrick metric flange bolt set 700Pcs M6-M10

Kadrick • ★ 4.0/5 • Budget

Comprehensive set of flange bolts, nuts, and washers totaling 700 pieces in metric sizes. Includes 175 bolts, 175 nuts, and 175 washers per size group, with black zinc plating for durability. Customers note good quality and handy case, with some mixed feedback on quantity
- comprehensive 700-piece set
- metric M6-M10 range
- case for organization
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2
Machine Screws Assortment Kit with hex socket bolts

mxuteuk • ★ 4.0/5 • Budget

Screws assortment including SAE & metric sizes with hex socket button head. Useful for multiple builds and drone motors, offering good variety and value
- mixed metric and SAE sizes
- high-strength 10.9 steel
- comprehensive hex socket bolt kit
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3
M6-M12 metric bolts and nuts set with washers

MYWISH • ★ 3.9/5 • Budget

Metric bolts and nuts assortment with M6 to M12 threads and washers. Includes variety of lengths and a universal socket tool for quick fittings. Customers note high quality and good value for a range of projects
- wide size range
- quality construction
- includes necessary hardware
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Buying Guide

Match bolt grades and material

Choose sets with the appropriate material and strength grade for your assembly—stainless or high-tensile steel for corrosion resistance and load-bearing applications

Confirm thread size range

Look for sets that cover the M6–M12 range if you need common metric sizes; smaller kits focused on M6–M10 are suitable for light-to-medium mechanical work

Prefer flange or socket heads by application

Flange bolts reduce the need for separate washers, while hex-socket (internal drive) bolts are better where a low-profile, tamper-resistant head is required

Check for included nuts and washers

Sets that include matched nuts and washers simplify assembly and ensure proper clamping; confirm washer types and quantities for your joint designs

Assess kit organization and labeling

Well-organized compartments and clear labeling speed selection and reduce fastener mismatch during repeated mechanical builds