#40 Roller Chain Sprocket B Type 1ft Bore 24 Tooth - Hardened Rust

Our review of the #40 Roller Chain Sprocket finds it a solid choice for DIY mechanics and light industrial users who need a durable, low-maintenance sprocket for 1/2' pitch drives. The standout reason to buy is its hardened AISI 1045 steel construction with tooth surface quenching and blackening treatment, which delivers wear resistance and rust protection for prolonged service without frequent lubrication. Fit can vary by installation, but for users prioritizing longevity and low upkeep, this sprocket performs reliably.

Key Features

• Material: Made from AISI 1045 medium carbon steel, the sprocket offers stronger core toughness than many stamped alternatives, which helps resist deformation under load.
• Hardened teeth: Teeth are heat treated to HRC38-42, providing wear resistance that extends service life in continuous chain drives.
• Rust prevention: The overall blackening surface treatment reduces corrosion, making it suitable for environments where moisture is present.
• Standard fitment: 12.7mm (1/2') pitch and 24 teeth match common #40 roller chain applications for easy replacement or retrofit.
• Secure mounting: 1' bore with a 0.25' keyway plus two setscrews at 90 degrees gives a stable shaft connection when properly aligned.
• Low maintenance: The design and treatments mean lubrication is not required frequently, reducing routine upkeep for long-term stable operation.

Who It's For

The sprocket is best for hobbyists, workshop machinists, and light industrial users who use #40 roller chain and need a rugged replacement sprocket that resists wear and rust. It is especially appropriate where continuous operation and reduced maintenance are priorities, such as small conveyors, shop-built machinery, or agricultural equipment.

Users who require precision machine alignment or an exacting chain fit should check chain alignment carefully before purchase, since some customers reported mixed fit experiences; heavy industrial drives with specialized tolerances may be better served by customized or higher-specification sprockets.

Pros & Cons

Pros

• High hardness teeth (HRC38-42) give clear durability advantages for prolonged use.
• Blackening and surface hardening improve corrosion resistance and reduce visible wear.
• Solid AISI 1045 construction offers good strength compared with softer materials.
• Includes two setscrews and a keyed bore for dependable mounting when installed correctly.

Cons

• Some users report mixed fitment with their existing chain or shafts, so verification of dimensions and alignment is important before installation.
• While low-maintenance, it may still require occasional checks in heavy-duty or high-speed applications.

Specifications

Pitch	12.7mm (1/2')
Teeth	24
Bore diameter	1'
Keyway	0.25' with key
Mounting	2 setscrews at 90 degrees (included)
Material	AISI 1045 medium carbon steel
Hardness	Hardened teeth HRC38-42

Our Verdict

The #40 Roller Chain Sprocket delivers good value for users who need a durable, rust-resistant sprocket for common 1/2' pitch applications. Its hardened AISI 1045 construction and blackening treatment make it a practical replacement part that reduces maintenance and holds up well in routine use; just confirm chain alignment and shaft dimensions before fitting to avoid installation issues.

Frequently Asked Questions

Does this sprocket include mounting hardware?
Yes, the package includes two setscrews for securing the sprocket to the shaft.

Will this sprocket require regular lubrication?
The sprocket is treated to reduce the need for frequent lubrication, though occasional checks are recommended for heavy or high-speed drives.

What chain pitch and tooth count does it fit?
It fits 12.7mm (1/2') pitch #40 roller chain and has 24 teeth.