# Martin 40BS21 1 Bored-to-Size Sprocket #40 Chain 1/2" Pitch 21 Teeth 1" Bore Steel Type B Finished Bore - MROSupply.com

***Martin 40BS21 1 Type B finished bore roller chain sprocket for #40 chain, 1/2" pitch, 21 teeth, 1" bore with keyway and setscrews. Steel construction, 3.617" outside diameter. Single-strand sprocket with hub on one side for re-boring or direct mounting.***



## Product details:

- Catalog number: 40BS21 1
- SKU: 261440
- Price: ***$47.31*** Each
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [Martin Sprocket](https://www.mrosupply.com/brands/martin-sprocket/)
- Category: 
    - [Type B Finished Bore Sprockets](htts://www.mrosupply.com/chains-sprockets/sprockets/roller-chain-sprockets/finished-bore-sprockets/type-b-finished-bore-sprockets/)
    - [Finished Bore Sprockets](htts://www.mrosupply.com/chains-sprockets/sprockets/roller-chain-sprockets/finished-bore-sprockets/)
    - [Roller Chain Sprockets](htts://www.mrosupply.com/chains-sprockets/sprockets/roller-chain-sprockets/)
    - [Sprockets](htts://www.mrosupply.com/chains-sprockets/sprockets/)
    - [Chains & Sprockets](htts://www.mrosupply.com/chains-sprockets/)
- Unit of measure: each
- Weight: 1.590 lb
- Technicall support: contact supplier for technical support on 323-728-8117


## Product images:
- https://static.mrosupply.com/images/noimage.webp


## Product attributes;

  
- Bore: 1"
  

  
- Material: Steel
  

  
- Number Of Teeth: 21
  

  
- Outside Dia: 3.617"
  

  
- Pitch: 0.500 in.
  

  
- Teeth: 21
  

## Suggested products:
- [Renold Jeffrey 40-1R PREMIUM ROLLER CHAIN 10 RIVETED](https://www.mrosupply.com/products/2182855/as-markdown/)
- [Martin 40A12 Type A plain bore roller chain sprocket for #40 chain, 1/2" pitch, 12 teeth, 2.166" outside diameter. Flat plate design with no hub, steel construction. Suitable for light-duty applications where a simple, economical sprocket is required.](https://www.mrosupply.com/products/261212/as-markdown/)
- [HKK RC040R1A 40R10 ANSI 40 single strand roller chain, 1/2" pitch, 10 ft reel. Solid bushings and rollers, pin diameter 0.156", plate height 0.457", roller diameter 0.312", roller width 5/16". Average ultimate strength 4,300 lbs, maximum allowable load 940 lbs. ANSI B29.1 compliant, made in Japan.](https://www.mrosupply.com/products/2265612/as-markdown/)
- [Martin 40A14 Type A plain bore roller chain sprocket for #40 chain (1/2" pitch) with 14 teeth. Flat plate design with no hub, made of steel. Outside diameter: 2.491". Compatible with ANSI B29.1 standard chain.](https://www.mrosupply.com/products/261214/as-markdown/)
- [Martin 40A112 Type A plain bore roller chain sprocket for #40 chain, 1/2" pitch, 112 teeth, 18.121" outside diameter. Flat plate design with no hub, steel construction. Suitable for applications requiring a lightweight, compact sprocket where hub projection is not needed.](https://www.mrosupply.com/products/261211/as-markdown/)

## Product's reviews:
- Perfect - Perfect replacement part, Good purchase experience. I would use MRO again.
- Nice sprocket - sprocket is very nice.
- Martin s1036 gears - Great Item, for a great deal!
- Nice sprocket - sprocket is very nice.