#40 Roller Chain Sprocket B Type 1ft Bore 36 Tooth - Hardened Rust

In this review the #40 Roller Chain Sprocket B Type is evaluated for light industrial and hobby drive systems where durability and low maintenance matter. The bottom line: this sprocket is for users who need a hardened, wear-resistant 36-tooth sprocket with a 1' bore and double set-screw retention that resists rust without frequent lubrication. It reviews well as a robust replacement or retrofit part when matched to a 12.7mm (1/2') pitch chain, offering long service life because the gear teeth receive high-temperature quenching and localized hardening.

Key Features

• 12.7mm (1/2') pitch: Matches standard #40 roller chains so you can replace or retrofit drives with predictable alignment when the chain and shaft are compatible.
• Hardened teeth: Teeth are surface hardened to HRC38-42, delivering improved wear resistance and longer life under cyclic loading.
• 1' bore with 0.25' keyway: The full 1' bore and quarter-inch keyway provide secure mounting for moderate torque applications with positive key engagement.
• Two setscrews at 90 degrees: Dual setscrews reduce shaft slip risk and make installation straightforward in confined mounting orientations.
• AISI 1045 medium carbon steel: The core material combined with quenching treatment gives a good balance of toughness and hardness for industrial use.
• Blackening rust protection: Overall blackening treatment helps resist corrosion so the sprocket needs less frequent upkeep in non-fully-sealed environments.

Who It's For

This sprocket is intended for hobbyists, small shops, and light industrial users who run #40 roller chain (12.7mm/1/2' pitch) and need a durable replacement or spare part. It is especially useful where lubrication is minimal or periodic and where rust resistance and hardened teeth reduce downtime for maintenance.

It is not aimed at high-precision or high-speed servo systems that require matched pitch accuracy and dynamic balancing beyond standard sprocket tolerances. If your application demands custom bore machining, specialized coatings, or stainless steel corrosion immunity for marine environments, consider alternatives designed for those conditions.

Pros & Cons

Pros

• High hardness and tooth surface treatment improve wear resistance and extend service life under typical chain loads.
• Solid AISI 1045 steel construction with quenching treatment balances toughness and durability for industrial use.
• Dual setscrews and keyed bore give secure mounting and straightforward installation on 1' shafts.
• Blackening finish provides basic corrosion resistance so the part remains usable with less maintenance.

Cons

• Fit can be mixed depending on existing chain alignment; some users may need minor adjustment or shimming to achieve perfect mesh.
• Not stainless or specially coated for harsh marine or highly corrosive environments.

Specifications

Pitch	12.7mm (1/2')
Teeth	36
Bore diameter	1' (1 inch)
Keyway	0.25' (1/4'') keyway
Retention	2 setscrews at 90 degrees (included)
Material	AISI 1045 medium carbon steel, quenched
Tooth hardness	HRC38-42

Our Verdict

The #40 Roller Chain Sprocket B Type is a solid, value-oriented choice for anyone needing a hardened 36-tooth sprocket with a 1' bore and reliable mounting hardware. Its heat-treated teeth and blackening finish deliver durability and rust resistance for light industrial and workshop use, making it a smart buy for replacements and retrofits where stainless or specialty coatings are not required.

Frequently Asked Questions

Does this sprocket fit #40 chain?
Yes, it is designed for 12.7mm (1/2') pitch, which corresponds to #40 roller chain, so compatibility is expected when chain wear is within tolerance.

Are the setscrews included?
Yes, the package includes the sprocket and 2 setscrews installed for 90 degree retention.

Does it require lubrication?
The sprocket is surface hardened and blackened for rust resistance and does not require lubrication, though periodic chain lubrication will extend overall drive life.