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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.

4SR14-BS-Stainless-Steel-Simplex-Pilot-Bore-08B-1/2"-Pitch-Sprocket-14-Tooth

4SR14 (08B-1-14) - BS Stainless Steel Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 14 Tooth

£15.96 - £15.96
£15.96
£15.96 - £15.96
£15.96

4SR14 Stainless Steel Pilot Bore 08B 1/2" Pitch Sprocket   For use with 08B-1 Simplex Chain   Part Number 4SR14 Pitch 1/2 Teeth 14 Outside...

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£15.96 - £15.96
£15.96
£15.96 - £15.96
£15.96
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

£16.85 - £16.85
£16.85
£16.85 - £16.85
£16.85

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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£16.85 - £16.85
£16.85
£16.85 - £16.85
£16.85
4tr27-pilot-bore-08b-1-2-pitch-sprocket

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

£15.68 - £15.68
£15.68
£15.68 - £15.68
£15.68

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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£15.68 - £15.68
£15.68
£15.68 - £15.68
£15.68
4tr14-pilot-bore-08b-1-2-pitch-sprocket

4TR14 (08B-3-14) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 14 Tooth

£6.09 - £6.09
£6.09
£6.09 - £6.09
£6.09

4TR14 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR14 Pitch 1/2 Teeth 14 Outside Dia (mm) 61.8 ...

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£6.09 - £6.09
£6.09
£6.09 - £6.09
£6.09
4dr57-pilot-bore-08b-1-2-pitch-sprocket

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

£43.17 - £43.17
£43.17
£43.17 - £43.17
£43.17

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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£43.17 - £43.17
£43.17
£43.17 - £43.17
£43.17
4dr38-pilot-bore-08b-1-2-pitch-sprocket

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

£21.23 - £21.23
£21.23
£21.23 - £21.23
£21.23

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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£21.23 - £21.23
£21.23
£21.23 - £21.23
£21.23
4dr23-pilot-bore-08b-1-2-pitch-sprocket

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

£8.22 - £8.22
£8.22
£8.22 - £8.22
£8.22

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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£8.22 - £8.22
£8.22
£8.22 - £8.22
£8.22
4dr21-pilot-bore-08b-1-2-pitch-sprocket

4DR21 (08B-2-21) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 21 Tooth

£7.74 - £7.74
£7.74
£7.74 - £7.74
£7.74

4DR21 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR21 Pitch 1/2 Teeth 21 Outside Dia (mm) 89.7 ...

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£7.74 - £7.74
£7.74
£7.74 - £7.74
£7.74
4dr20-pilot-bore-08b-1-2-pitch-sprocket

4DR20 (08B-2-20) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 20 Tooth

£6.40 - £6.40
£6.40
£6.40 - £6.40
£6.40

4DR20 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR20 Pitch 1/2 Teeth 20 Outside Dia (mm) 85.8 ...

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£6.40 - £6.40
£6.40
£6.40 - £6.40
£6.40
4dr19-pilot-bore-08b-1-2-pitch-sprocket

4DR19 (08B-2-19) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 19 Tooth

£6.40 - £6.40
£6.40
£6.40 - £6.40
£6.40

4DR19 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR19 Pitch 1/2 Teeth 19 Outside Dia (mm) 81.7 ...

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£6.40 - £6.40
£6.40
£6.40 - £6.40
£6.40
4dr10-pilot-bore-08b-1-2-pitch-sprocket

4DR10 (08B-2-10) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 10 Tooth

£2.81 - £2.81
£2.81
£2.81 - £2.81
£2.81

4DR10 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR10 Pitch 1/2 Teeth 10 Outside Dia (mm) 45.2 ...

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£2.81 - £2.81
£2.81
£2.81 - £2.81
£2.81
4sr40-pilot-bore-08b-1-2-pitch-sprocket

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

£11.69 - £11.69
£11.69
£11.69 - £11.69
£11.69

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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£11.69 - £11.69
£11.69
£11.69 - £11.69
£11.69
4sr31-pilot-bore-08b-1-2-pitch-sprocket

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

£8.71 - £8.71
£8.71
£8.71 - £8.71
£8.71

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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£8.71 - £8.71
£8.71
£8.71 - £8.71
£8.71
4sr30-pilot-bore-08b-1-2-pitch-sprocket

4SR30 (08B-1-30) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 30 Tooth

£7.64 - £7.64
£7.64
£7.64 - £7.64
£7.64

4SR30 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR30 Pitch 1/2 Teeth 30 Outside Dia (mm) 126.1 ...

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£7.64 - £7.64
£7.64
£7.64 - £7.64
£7.64
4sr25-pilot-bore-08b-1-2-pitch-sprocket

4SR25 (08B-1-25) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 25 Tooth

£6.50 - £6.50
£6.50
£6.50 - £6.50
£6.50

4SR25 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR25 Pitch 1/2 Teeth 25 Outside Dia (mm) 105.8 ...

View full details
£6.50 - £6.50
£6.50
£6.50 - £6.50
£6.50
4sr24-pilot-bore-08b-1-2-pitch-sprocket

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

£6.26 - £6.26
£6.26
£6.26 - £6.26
£6.26

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
£6.26 - £6.26
£6.26
£6.26 - £6.26
£6.26
4sr23-pilot-bore-08b-1-2-pitch-sprocket

4SR23 (08B-1-23) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 23 Tooth

£6.04 - £6.04
£6.04
£6.04 - £6.04
£6.04

4SR23 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR23 Pitch 1/2 Teeth 23 Outside Dia (mm) 98.2 ...

View full details
£6.04 - £6.04
£6.04
£6.04 - £6.04
£6.04
4sr22-pilot-bore-08b-1-2-pitch-sprocket

4SR22 (08B-1-22) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 22 Tooth

£5.74 - £5.74
£5.74
£5.74 - £5.74
£5.74

4SR22 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR22 Pitch 1/2 Teeth 22 Outside Dia (mm) 93.8 ...

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£5.74 - £5.74
£5.74
£5.74 - £5.74
£5.74
4sr17-pilot-bore-08b-1-2-pitch-sprocket

4SR17 (08B-1-17) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 17 Tooth

£3.84 - £3.84
£3.84
£3.84 - £3.84
£3.84

4SR17 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR17 Pitch 1/2 Teeth 17 Outside Dia (mm) 73.6 ...

View full details
£3.84 - £3.84
£3.84
£3.84 - £3.84
£3.84
4sr38-pilot-bore-08b-1-2-pitch-sprocket

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

£22.51 - £22.51
£22.51
£22.51 - £22.51
£22.51

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

£22.51 - £22.51
£22.51
£22.51 - £22.51
£22.51
4sr45-pilot-bore-08b-1-2-pitch-sprocket

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

£28.44 - £28.44
£28.44
£28.44 - £28.44
£28.44

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

£28.44 - £28.44
£28.44
£28.44 - £28.44
£28.44
4sr57-pilot-bore-08b-1-2-pitch-sprocket

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

£34.31 - £34.31
£34.31
£34.31 - £34.31
£34.31

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

£34.31 - £34.31
£34.31
£34.31 - £34.31
£34.31
4sr76-pilot-bore-08b-1-2-pitch-sprocket

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

£51.14 - £51.14
£51.14
£51.14 - £51.14
£51.14

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

£51.14 - £51.14
£51.14
£51.14 - £51.14
£51.14
4sr95-pilot-bore-08b-1-2-pitch-sprocket

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

£84.95 - £84.95
£84.95
£84.95 - £84.95
£84.95

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

£84.95 - £84.95
£84.95
£84.95 - £84.95
£84.95

Hi. Need any help?