Metric Flange Bolt and Nut Assortment Kit 320pcs - Organized High

In this review of the 320-piece metric flange bolt and nut assortment, the bottom line is simple: this kit is for technicians, mechanics, and DIYers who need a compact, well-organized selection of high-strength metric fasteners ready for equipment mounting and repairs. The reviewer found the combination of fully threaded Grade 10.9 carbon steel bolts, serrated flange nuts, and both flat and spring lock washers to be the single biggest reason to buy, because they deliver dependable holding power in vibration-prone and load-bearing applications while stored neatly in a reusable case.

Key Features

• Full thread metric bolts: Includes M6, M8 and M10 sizes across nine length options so the kit covers common metric fastening needs without guessing.
• Grade 10.9 carbon steel: Hardened material provides higher tensile strength and improved torque performance for mechanical and structural tasks.
• Serrated flange nuts: Built-in serrations increase grip and help resist loosening under vibration compared with plain nuts.
• Black oxide finish with light oil: Surface treatment helps protect parts in storage and makes the set compatible with additional anti-rust oiling for exposed use.
• Flat and spring lock washers: Included washers let the user tailor assemblies for clamping or anti-rotation protection in the same kit.
• Reusable plastic case with size chart: Pre-sorted compartments and a printed chart speed up part selection and keep the set portable for workshops or field service.

Who It's For

This kit suits maintenance crews, garage mechanics, and hobbyists who frequently work on equipment mounting, frame assemblies, engine brackets, or other projects where metric flange bolts and locking nuts are required. The range of M6 and M8 lengths plus an M10 option covers most light- to medium-duty fastening tasks encountered in a typical workshop.

Those who need stainless steel or specialized corrosion resistance for long-term outdoor marine exposure should look elsewhere, since this set uses black oxide carbon steel with light oil rather than stainless alloys. If you require long metric stud lengths beyond the supplied sizes, a custom fastener source may be preferable.

Pros & Cons

Pros

• High-strength Grade 10.9 bolts and serrated nuts provide secure clamping and good torque capacity.
• Comprehensive assortment with washers and a clear storage case keeps parts organized and portable.
• Black oxide plus factory oil gives reasonable protection in storage and accepts further anti-rust treatment for exposed use.

Cons

• Not stainless steel, so long-term corrosion resistance in harsh outdoor or marine environments is limited unless additional coatings are applied.

Specifications

Kit quantity	320 pieces
Bolt sizes	M6 x 1.0, M8 x 1.25, M10 x 1.5
Bolt lengths	M6: 12,16,20,25,30mm; M8: 16,20,25,30mm; M10: 30mm
Material and grade	Grade 10.9 carbon steel
Finish	Black oxide with light factory oil
Included hardware	Flange bolts, serrated flange nuts, flat washers, spring lock washers
Storage	Reusable plastic case with printed size chart

Our Verdict

For professionals and hobbyists who need a ready-to-use metric flange bolt assortment, this 320-piece kit is a practical value: the Grade 10.9 carbon steel fasteners and serrated nuts deliver strong, vibration-resistant fastening, and the organized case speeds workflow. It is a smart choice when high tensile strength and on-hand variety matter, though those needing inherent stainless corrosion resistance should consider alternative alloys.

Frequently Asked Questions

Are the bolts fully threaded?
Yes, all bolts in the set are fully threaded to the lengths listed, which helps when matching nut placement on short assemblies.

Is the kit suitable for outdoor use?
The black oxide finish and light oil protect parts in storage; for prolonged outdoor or marine exposure additional anti-rust treatment is recommended.

Does the case include a size chart?
Yes, the reusable plastic case includes a printed size chart to identify and sort parts quickly.