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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.

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

4DR76 (08B-2-76) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£72.80 - £72.80
£72.80
£72.80 - £72.80
£72.80

4DR76 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR76 Pitch 1/2 Teeth 76 Outside Dia (mm) 313.3 ...

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£72.80 - £72.80
£72.80
£72.80 - £72.80
£72.80
4dr45-pilot-bore-08b-1-2-pitch-sprocket

4DR45 (08B-2-45) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

£30.11 - £30.11
£30.11
£30.11 - £30.11
£30.11

4DR45 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR45 Pitch 1/2 Teeth 45 Outside Dia (mm) 188 O...

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£30.11 - £30.11
£30.11
£30.11 - £30.11
£30.11
4dr40-pilot-bore-08b-1-2-pitch-sprocket

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

£22.79 - £22.79
£22.79
£22.79 - £22.79
£22.79

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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£22.79 - £22.79
£22.79
£22.79 - £22.79
£22.79
4dr39-pilot-bore-08b-1-2-pitch-sprocket

4DR39 (08B-2-39) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 39 Tooth

£21.93 - £21.93
£21.93
£21.93 - £21.93
£21.93

4DR39 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR39 Pitch 1/2 Teeth 39 Outside Dia (mm) 162.7 ...

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£21.93 - £21.93
£21.93
£21.93 - £21.93
£21.93
4dr37-pilot-bore-08b-1-2-pitch-sprocket

4DR37 (08B-2-37) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 37 Tooth

£20.47 - £20.47
£20.47
£20.47 - £20.47
£20.47

4DR37 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR37 Pitch 1/2 Teeth 37 Outside Dia (mm) 154.6 ...

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£20.47 - £20.47
£20.47
£20.47 - £20.47
£20.47
4dr36-pilot-bore-08b-1-2-pitch-sprocket

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

£19.72 - £19.72
£19.72
£19.72 - £19.72
£19.72

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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£19.72 - £19.72
£19.72
£19.72 - £19.72
£19.72
4dr35-pilot-bore-08b-1-2-pitch-sprocket

4DR35 (08B-2-35) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 35 Tooth

£17.88 - £17.88
£17.88
£17.88 - £17.88
£17.88

4DR35 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR35 Pitch 1/2 Teeth 35 Outside Dia (mm) 146.7 ...

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£17.88 - £17.88
£17.88
£17.88 - £17.88
£17.88
4dr34-pilot-bore-08b-1-2-pitch-sprocket

4DR34 (08B-2-34) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 34 Tooth

£17.17 - £17.17
£17.17
£17.17 - £17.17
£17.17

4DR34 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR34 Pitch 1/2 Teeth 34 Outside Dia (mm) 142.6 ...

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£17.17 - £17.17
£17.17
£17.17 - £17.17
£17.17
4dr33-pilot-bore-08b-1-2-pitch-sprocket

4DR33 (08B-2-33) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 33 Tooth

£16.57 - £16.57
£16.57
£16.57 - £16.57
£16.57

4DR33 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR33 Pitch 1/2 Teeth 33 Outside Dia (mm) 138.4...

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£16.57 - £16.57
£16.57
£16.57 - £16.57
£16.57
4dr31-pilot-bore-08b-1-2-pitch-sprocket

4DR31 (08B-2-31) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 31 Tooth

£15.25 - £15.25
£15.25
£15.25 - £15.25
£15.25

4DR31 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR31 Pitch 1/2 Teeth 31 Outside Dia (mm) 130.2...

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£15.25 - £15.25
£15.25
£15.25 - £15.25
£15.25
4dr30-pilot-bore-08b-1-2-pitch-sprocket

4DR30 (08B-2-30) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 30 Tooth

£14.50 - £14.50
£14.50
£14.50 - £14.50
£14.50

4DR30 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR30 Pitch 1/2 Teeth 30 Outside Dia (mm) 126.1...

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£14.50 - £14.50
£14.50
£14.50 - £14.50
£14.50
4dr29-pilot-bore-08b-1-2-pitch-sprocket

4DR29 (08B-2-29) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 29 Tooth

£13.59 - £13.59
£13.59
£13.59 - £13.59
£13.59

4DR29 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR29 Pitch 1/2 Teeth 29 Outside Dia (mm) 122 ...

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£13.59 - £13.59
£13.59
£13.59 - £13.59
£13.59
4dr28-pilot-bore-08b-1-2-pitch-sprocket

4DR28 (08B-2-28) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 28 Tooth

£12.50 - £12.50
£12.50
£12.50 - £12.50
£12.50

4DR28 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR28 Pitch 1/2 Teeth 28 Outside Dia (mm) 118 ...

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£12.50 - £12.50
£12.50
£12.50 - £12.50
£12.50
4dr27-pilot-bore-08b-1-2-pitch-sprocket

4DR27 (08B-2-27) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 27 Tooth

£11.51 - £11.51
£11.51
£11.51 - £11.51
£11.51

4DR27 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR27 Pitch 1/2 Teeth 27 Outside Dia (mm) 114 ...

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£11.51 - £11.51
£11.51
£11.51 - £11.51
£11.51
4dr26-pilot-bore-08b-1-2-pitch-sprocket

4DR26 (08B-2-26) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 26 Tooth

£11.02 - £11.02
£11.02
£11.02 - £11.02
£11.02

4DR26 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR26 Pitch 1/2 Teeth 26 Outside Dia (mm) 110 ...

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£11.02 - £11.02
£11.02
£11.02 - £11.02
£11.02
4dr25-pilot-bore-08b-1-2-pitch-sprocket

4DR25 (08B-2-25) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 25 Tooth

£10.03 - £10.03
£10.03
£10.03 - £10.03
£10.03

4DR25 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR25 Pitch 1/2 Teeth 25 Outside Dia (mm) 105.8...

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£10.03 - £10.03
£10.03
£10.03 - £10.03
£10.03
4dr24-pilot-bore-08b-1-2-pitch-sprocket

4DR24 (08B-2-24) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 24 Tooth

£9.32 - £9.32
£9.32
£9.32 - £9.32
£9.32

4DR24 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR24 Pitch 1/2 Teeth 24 Outside Dia (mm) 101.8...

View full details
£9.32 - £9.32
£9.32
£9.32 - £9.32
£9.32
4dr22-pilot-bore-08b-1-2-pitch-sprocket

4DR22 (08B-2-22) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 22 Tooth

£7.80 - £7.80
£7.80
£7.80 - £7.80
£7.80

4DR22 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR22 Pitch 1/2 Teeth 22 Outside Dia (mm) 93.8 ...

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£7.80 - £7.80
£7.80
£7.80 - £7.80
£7.80
4dr18-pilot-bore-08b-1-2-pitch-sprocket

4DR18 (08B-2-18) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 18 Tooth

£5.77 - £5.77
£5.77
£5.77 - £5.77
£5.77

4DR18 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR18 Pitch 1/2 Teeth 18 Outside Dia (mm) 77.8 ...

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£5.77 - £5.77
£5.77
£5.77 - £5.77
£5.77
4dr16-pilot-bore-08b-1-2-pitch-sprocket

4DR16 (08B-2-16) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 16 Tooth

£5.15 - £5.15
£5.15
£5.15 - £5.15
£5.15

4DR16 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR16 Pitch 1/2 Teeth 16 Outside Dia (mm) 69.5 ...

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£5.15 - £5.15
£5.15
£5.15 - £5.15
£5.15
4dr08-pilot-bore-08b-1-2-pitch-sprocket

4DR08 (08B-2-08) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 8 Tooth

£2.27 - £2.27
£2.27
£2.27 - £2.27
£2.27

4DR08 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR08 Pitch 1/2 Teeth 8 Outside Dia (mm) 37.2 O...

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£2.27 - £2.27
£2.27
£2.27 - £2.27
£2.27
4sr95-pilot-bore-08b-1-2-pitch-sprocket

4SR95 (08B-1-95) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£47.76 - £47.76
£47.76
£47.76 - £47.76
£47.76

4SR95 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR95 Pitch 1/2 Teeth 95 Outside Dia (mm) 390.1 ...

View full details
£47.76 - £47.76
£47.76
£47.76 - £47.76
£47.76
4sr76-pilot-bore-08b-1-2-pitch-sprocket

4SR76 (08B-1-76) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 76 Tooth

£33.38 - £33.38
£33.38
£33.38 - £33.38
£33.38

4SR76 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR76 Pitch 1/2 Teeth 76 Outside Dia (mm) 313.3 ...

View full details
£33.38 - £33.38
£33.38
£33.38 - £33.38
£33.38
4sr57-pilot-bore-08b-1-2-pitch-sprocket

4SR57 (08B-1-57) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 57 Tooth

£20.42 - £20.42
£20.42
£20.42 - £20.42
£20.42

4SR57 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR57 Pitch 1/2 Teeth 57 Outside Dia (mm) 236.4 ...

View full details
£20.42 - £20.42
£20.42
£20.42 - £20.42
£20.42

Hi. Need any help?