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Pilot Bore Sprockets – 1/2” Pitch Roller Chain Sprockets

At Bolton Engineering Products Ltd, we stock a full range of pilot bore sprockets designed for reliable, efficient power transmission in machinery, conveyors, automation systems, and chain-driven equipment.

These plain bore sprockets (Type A) have an unprepared bore and require a keyway and set screw for installation, allowing them to be fully customized to fit any shaft size and meet your specific needs.

BEP Ltd have you covered – whether it be a light-duty sprocket or an item designed for continuous use, all our parts are made from high-strength materials and custom machined to tight tolerances at very competitive prices.

What Is a Pilot Bore Sprocket?

A pilot bore sprocket is a chain sprocket supplied with a basic, oversized bore, allowing engineers or machinists to finish-machine it to the exact shaft diameter or keyway required.

These sprockets are popular in:

  • Manufacturing & processing equipment
  • Agricultural and industrial machinery
  • Conveyors and material handling systems
  • Motorcycles, bicycles & chain-driven vehicles
  • General engineering and fabrication workshops

Their flexibility makes them a go-to choice for custom drive systems and OEM applications.

Technical Specifications

Specification

Details

Product Type

Pilot Bore / Plain Bore Sprocket

Chain Pitch

1/2” Pitch (BS Standard Roller Chain)

Tooth Count Options

8T to 50T+

Material

C45 Steel / Hardened Steel

Bore Type

Pilot Bore (Machinable to Required Shaft Size)

Mounting Style

Direct Shaft, Hub, or Bushing Mount

Tooth Profile

British Standard (BS / ISO Chain)

Applications

Industrial, Agricultural, Conveyor, Mechanical Drives

Finish

Untreated / Phosphate / Black Oxide (model dependent)

Key Features & Benefits

  • Customizable Bore: Machine the bore and keyway exactly as required.
  • Smooth Power Transfer: Precisely machined teeth ensure accurate chain engagement.
  • High-quality Steel made: Any types of metal work, 5” Heavy Duty.
  • Large Size Range: Will work small equipment all the way up to large industrial machinery.
  • Also compatible with BS standard: Suits all 1/2" pitch standard roller chains.
  • Bulk order discount: Great for OEMs, garages and maintenance facilities.

Why Choose Bolton Engineering Products Ltd?

As one of the UK’s trusted suppliers of pilot bore sprockets, BEP Ltd offers:

  • Large inventory of plain bore sprockets in multiple tooth counts
  • High-quality components sourced from reliable manufacturers
  • Competitive prices with trade & bulk discounts
  • Expert technical support for sizing and application queries
  • Fast UK dispatch with reliable shipping options

When you need precision, durability, and flexibility, BEP Ltd has the right pilot bore sprocket for your job.

FAQs

Q1: What is the difference between a pilot bore sprocket and a finished bore sprocket?

A pilot bore sprocket has an oversized bore that requires machining. A finished bore sprocket comes pre-machined to a specific shaft size.

Q2: Is a pilot bore the same as a plain bore?

Yes — plain bore sprockets and pilot bore sprockets describe the same unfinished, machinable bore design.

Q3: Can I machine the bore myself?

Yes. Many customers machine the bore, keyway, and grub-screw holes in-house. We can also advise on machining allowances.

Q4: Are these sprockets compatible with standard roller chains?

Absolutely. All our sprockets fit 1/2” pitch BS roller chains.

Roller Chain Pilot Bore Sprockets - 1/2"

Pilot Bore Sprockets – 1/2” Pitch Roller Chain Sprockets

At Bolton Engineering Products Ltd, we stock a full range of pilot bore sprockets designed for reliable, efficient power transmission in machinery, conveyors, automation systems, and chain-driven equipment.

These plain bore sprockets (Type A) have an unprepared bore and require a keyway and set screw for installation, allowing them to be fully customized to fit any shaft size and meet your specific needs.

BEP Ltd have you covered – whether it be a light-duty sprocket or an item designed for continuous use, all our parts are made from high-strength materials and custom machined to tight tolerances at very competitive prices.

What Is a Pilot Bore Sprocket?

A pilot bore sprocket is a chain sprocket supplied with a basic, oversized bore, allowing engineers or machinists to finish-machine it to the exact shaft diameter or keyway required.

These sprockets are popular in:

  • Manufacturing & processing equipment
  • Agricultural and industrial machinery
  • Conveyors and material handling systems
  • Motorcycles, bicycles & chain-driven vehicles
  • General engineering and fabrication workshops

Their flexibility makes them a go-to choice for custom drive systems and OEM applications.

Technical Specifications

Specification

Details

Product Type

Pilot Bore / Plain Bore Sprocket

Chain Pitch

1/2” Pitch (BS Standard Roller Chain)

Tooth Count Options

8T to 50T+

Material

C45 Steel / Hardened Steel

Bore Type

Pilot Bore (Machinable to Required Shaft Size)

Mounting Style

Direct Shaft, Hub, or Bushing Mount

Tooth Profile

British Standard (BS / ISO Chain)

Applications

Industrial, Agricultural, Conveyor, Mechanical Drives

Finish

Untreated / Phosphate / Black Oxide (model dependent)

Key Features & Benefits

  • Customizable Bore: Machine the bore and keyway exactly as required.
  • Smooth Power Transfer: Precisely machined teeth ensure accurate chain engagement.
  • High-quality Steel made: Any types of metal work, 5” Heavy Duty.
  • Large Size Range: Will work small equipment all the way up to large industrial machinery.
  • Also compatible with BS standard: Suits all 1/2" pitch standard roller chains.
  • Bulk order discount: Great for OEMs, garages and maintenance facilities.

Why Choose Bolton Engineering Products Ltd?

As one of the UK’s trusted suppliers of pilot bore sprockets, BEP Ltd offers:

  • Large inventory of plain bore sprockets in multiple tooth counts
  • High-quality components sourced from reliable manufacturers
  • Competitive prices with trade & bulk discounts
  • Expert technical support for sizing and application queries
  • Fast UK dispatch with reliable shipping options

When you need precision, durability, and flexibility, BEP Ltd has the right pilot bore sprocket for your job.

FAQs

Q1: What is the difference between a pilot bore sprocket and a finished bore sprocket?

A pilot bore sprocket has an oversized bore that requires machining. A finished bore sprocket comes pre-machined to a specific shaft size.

Q2: Is a pilot bore the same as a plain bore?

Yes — plain bore sprockets and pilot bore sprockets describe the same unfinished, machinable bore design.

Q3: Can I machine the bore myself?

Yes. Many customers machine the bore, keyway, and grub-screw holes in-house. We can also advise on machining allowances.

Q4: Are these sprockets compatible with standard roller chains?

Absolutely. All our sprockets fit 1/2” pitch BS roller chains.

4SR13 16mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 13 Tooth

£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

Roller Chain Sprocket 08B 4SR13 16mm Bore Key & 2 Set Screws 1/2" Pitch 13 ToothChain Pitch:08B-1Number of Teeth:13Bore & Keyway(mm):16mmMf...

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£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

4SR13 15mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 13 Tooth

£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

Roller Chain Sprocket 08B 4SR13 15mm Bore Key & 2 Set Screws 1/2" Pitch 13 ToothChain Pitch:08B-1Number of Teeth:13Bore & Keyway(mm):15mmMf...

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£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

4SR12 19mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 12 Tooth

£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54

Roller Chain Sprocket 08B 4SR12 19mm Bore Key & 2 Set Screws 1/2" Pitch 12 ToothChain Pitch:08B-1Number of Teeth:12Bore & Keyway(mm):19mmMf...

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£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54

4SR12 15mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 12 Tooth

£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54

Roller Chain Sprocket 08B 4SR12 15mm Bore Key & 2 Set Screws 1/2" Pitch 12 ToothChain Pitch:08B-1Number of Teeth:12Bore & Keyway(mm):15mmMf...

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£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54
4SR16-BS-Stainless-Steel-Simplex-Pilot-Bore-08B-1/2"-Pitch-Sprocket-16-Tooth

4SR16 (08B-1-16) - BS Stainless Steel Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 16 Tooth

£15.18 - £15.18
£15.18
£15.18 - £15.18
£15.18

4SR16 Stainless Steel Pilot Bore 08B 1/2" Pitch Sprocket   For use with 08B-1 Simplex Chain   Part Number 4SR16 Pitch 1/2 Teeth 16 Outsi...

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£15.18 - £15.18
£15.18
£15.18 - £15.18
£15.18
4tr27-pilot-bore-08b-1-2-pitch-sprocket

4TR27 (08B-3-27) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 27 Tooth

£14.12 - £14.12
£14.12
£14.12 - £14.12
£14.12

4TR27 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR27 Pitch 1/2 Teeth 27 Outside Dia (mm) 114 ...

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£14.12 - £14.12
£14.12
£14.12 - £14.12
£14.12
4dr57-pilot-bore-08b-1-2-pitch-sprocket

4DR57 (08B-2-57) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£38.90 - £38.90
£38.90
£38.90 - £38.90
£38.90

4DR57 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR57 Pitch 1/2 Teeth 57 Outside Dia (mm) 236.4 ...

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£38.90 - £38.90
£38.90
£38.90 - £38.90
£38.90
4dr40-pilot-bore-08b-1-2-pitch-sprocket

4DR40 (08B-2-40) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 40 Tooth

£20.55 - £20.55
£20.55
£20.55 - £20.55
£20.55

4DR40 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR40 Pitch 1/2 Teeth 40 Outside Dia (mm) 166.8 ...

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£20.55 - £20.55
£20.55
£20.55 - £20.55
£20.55
4dr38-pilot-bore-08b-1-2-pitch-sprocket

4DR38 (08B-2-38) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 38 Tooth

£19.13 - £19.13
£19.13
£19.13 - £19.13
£19.13

4DR38 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR38 Pitch 1/2 Teeth 38 Outside Dia (mm) 158.6 ...

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£19.13 - £19.13
£19.13
£19.13 - £19.13
£19.13
4dr36-pilot-bore-08b-1-2-pitch-sprocket

4DR36 (08B-2-36) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 36 Tooth

£17.77 - £17.77
£17.77
£17.77 - £17.77
£17.77

4DR36 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR36 Pitch 1/2 Teeth 36 Outside Dia (mm) 151 O...

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£17.77 - £17.77
£17.77
£17.77 - £17.77
£17.77
4dr23-pilot-bore-08b-1-2-pitch-sprocket

4DR23 (08B-2-23) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 23 Tooth

£7.40 - £7.40
£7.40
£7.40 - £7.40
£7.40

4DR23 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR23 Pitch 1/2 Teeth 23 Outside Dia (mm) 98.2 ...

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£7.40 - £7.40
£7.40
£7.40 - £7.40
£7.40
4sr40-pilot-bore-08b-1-2-pitch-sprocket

4SR40 (08B-1-40) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 40 Tooth

£10.54 - £10.54
£10.54
£10.54 - £10.54
£10.54

4SR40 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR40 Pitch 1/2 Teeth 40 Outside Dia (mm) 166.8 ...

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£10.54 - £10.54
£10.54
£10.54 - £10.54
£10.54
4sr31-pilot-bore-08b-1-2-pitch-sprocket

4SR31 (08B-1-31) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 31 Tooth

£7.85 - £7.85
£7.85
£7.85 - £7.85
£7.85

4SR31 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR31 Pitch 1/2 Teeth 31 Outside Dia (mm) 130.2 ...

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£7.85 - £7.85
£7.85
£7.85 - £7.85
£7.85
4sr28-pilot-bore-08b-1-2-pitch-sprocket

4SR28 (08B-1-28) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 28 Tooth

£5.32 - £5.32
£5.32
£5.32 - £5.32
£5.32

4SR28 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR28 Pitch 1/2 Teeth 28 Outside Dia (mm) 118 ...

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£5.32 - £5.32
£5.32
£5.32 - £5.32
£5.32
4sr24-pilot-bore-08b-1-2-pitch-sprocket

4SR24 (08B-1-24) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 24 Tooth

£5.64 - £5.64
£5.64
£5.64 - £5.64
£5.64

4SR24 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR24 Pitch 1/2 Teeth 24 Outside Dia (mm) 101.8 ...

View full details
£5.64 - £5.64
£5.64
£5.64 - £5.64
£5.64
4sr38-pilot-bore-08b-1-2-pitch-sprocket

4SR38C (08B-1-38) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 38 Tooth

£20.28 - £20.28
£20.28
£20.28 - £20.28
£20.28

4SR38C (08B-1-38) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 38 Tooth

£20.28 - £20.28
£20.28
£20.28 - £20.28
£20.28
4sr45-pilot-bore-08b-1-2-pitch-sprocket

4SR45C (08B-1-45) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

£25.62 - £25.62
£25.62
£25.62 - £25.62
£25.62

4SR45C (08B-1-45) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

£25.62 - £25.62
£25.62
£25.62 - £25.62
£25.62
4sr57-pilot-bore-08b-1-2-pitch-sprocket

4SR57C (08B-1-57) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£30.92 - £30.92
£30.92
£30.92 - £30.92
£30.92

4SR57C (08B-1-57) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£30.92 - £30.92
£30.92
£30.92 - £30.92
£30.92
4sr76-pilot-bore-08b-1-2-pitch-sprocket

4SR76C (08B-1-76) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£46.09 - £46.09
£46.09
£46.09 - £46.09
£46.09

4SR76C (08B-1-76) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£46.09 - £46.09
£46.09
£46.09 - £46.09
£46.09
4sr95-pilot-bore-08b-1-2-pitch-sprocket

4SR95C (08B-1-95) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£76.56 - £76.56
£76.56
£76.56 - £76.56
£76.56

4SR95C (08B-1-95) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£76.56 - £76.56
£76.56
£76.56 - £76.56
£76.56
4dr45-pilot-bore-08b-1-2-pitch-sprocket

4DR45C (08B-2-45) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

£40.29 - £40.29
£40.29
£40.29 - £40.29
£40.29

4DR45C (08B-2-45) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

£40.29 - £40.29
£40.29
£40.29 - £40.29
£40.29
4dr57-pilot-bore-08b-1-2-pitch-sprocket

4DR57C (08B-2-57) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£41.85 - £41.85
£41.85
£41.85 - £41.85
£41.85

4DR57C (08B-2-57) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£41.85 - £41.85
£41.85
£41.85 - £41.85
£41.85
4dr76-pilot-bore-08b-1-2-pitch-sprocket

4DR76C (08B-2-76) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£73.17 - £73.17
£73.17
£73.17 - £73.17
£73.17

4DR76C (08B-2-76) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£73.17 - £73.17
£73.17
£73.17 - £73.17
£73.17
4dr95-pilot-bore-08b-1-2-pitch-sprocket

4DR95C (08B-2-95) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£94.40 - £94.40
£94.40
£94.40 - £94.40
£94.40

4DR95C (08B-2-95) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£94.40 - £94.40
£94.40
£94.40 - £94.40
£94.40

Hi. Need any help?