Fuji Locknuts | McMaster-Carr

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10 Products

Spring-Stop Locknuts

These locknuts withstand heavy vibration similar to distorted-thread nuts, and you can use them over and over. The prongs at the top bend when tightened to create tension for a secure hold. As you remove the locknut, the prongs spring back to their original shape, so you can install the nut again without losing holding power. Also known as Fuji locknuts.

Low-Strength Steel

Rated Grade 2, Class 6, or lower, these locknuts are about half as strong as medium-strength steel nuts. Use them with screws that have a similar strength rating to avoid stripping threads during installation.

Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M5 × 0.8 mm	8	4.6	Class 6	10	90508A110	000000


	M6 × 1 mm	10	5.1	Class 6	10	90508A120	00000
	M8 × 1.25 mm	12	7.3	Class 6	10	90508A130	00000
	M10 × 1.25 mm	14	8.5	Class 6	5	90508A150	0000
	M10 × 1.5 mm	17	8.5	Class 6	10	90508A140	00000
	M12 × 1.25 mm	17	10.4	Class 6	1	90508A160	0000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

	Wd., mm	Ht., mm	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M5 × 0.8 mm	8	4.8	10	90543A110	000000


	M6 × 1 mm	10	5.1	5	90543A120	0000
	M8 × 1.25 mm	13	7.2	5	90543A130	00000
	M10 × 1.5 mm	17	9.2	1	90543A140	0000