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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.

4tr36-pilot-bore-08b-1-2-pitch-sprocket

4TR36 (08B-3-36) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 36 Tooth

£26.03 - £26.03
£26.03
£26.03 - £26.03
£26.03

4TR36 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR36 Pitch 1/2 Teeth 36 Outside Dia (mm) 151 ...

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£26.03 - £26.03
£26.03
£26.03 - £26.03
£26.03
4tr35-pilot-bore-08b-1-2-pitch-sprocket

4TR35 (08B-3-35) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 35 Tooth

£23.95 - £23.95
£23.95
£23.95 - £23.95
£23.95

4TR35 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR35 Pitch 1/2 Teeth 35 Outside Dia (mm) 146.7 ...

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£23.95 - £23.95
£23.95
£23.95 - £23.95
£23.95
4tr34-pilot-bore-08b-1-2-pitch-sprocket

4TR34 (08B-3-34) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 34 Tooth

£23.05 - £23.05
£23.05
£23.05 - £23.05
£23.05

4TR34 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR34 Pitch 1/2 Teeth 34 Outside Dia (mm) 142.6 ...

View full details
£23.05 - £23.05
£23.05
£23.05 - £23.05
£23.05
4tr32-pilot-bore-08b-1-2-pitch-sprocket

4TR32 (08B-3-32) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 32 Tooth

£21.04 - £21.04
£21.04
£21.04 - £21.04
£21.04

4TR32 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR32 Pitch 1/2 Teeth 32 Outside Dia (mm) 134.3 ...

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£21.04 - £21.04
£21.04
£21.04 - £21.04
£21.04
4tr31-pilot-bore-08b-1-2-pitch-sprocket

4TR31 (08B-3-31) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 31 Tooth

£20.13 - £20.13
£20.13
£20.13 - £20.13
£20.13

4TR31 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR31 Pitch 1/2 Teeth 31 Outside Dia (mm) 130.2 ...

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£20.13 - £20.13
£20.13
£20.13 - £20.13
£20.13
4tr30-pilot-bore-08b-1-2-pitch-sprocket

4TR30 (08B-3-30) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 30 Tooth

£18.37 - £18.37
£18.37
£18.37 - £18.37
£18.37

4TR30 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR30 Pitch 1/2 Teeth 30 Outside Dia (mm) 126.1 ...

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£18.37 - £18.37
£18.37
£18.37 - £18.37
£18.37
4tr29-pilot-bore-08b-1-2-pitch-sprocket

4TR29 (08B-3-29) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 29 Tooth

£17.02 - £17.02
£17.02
£17.02 - £17.02
£17.02

4TR29 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR29 Pitch 1/2 Teeth 29 Outside Dia (mm) 122 ...

View full details
£17.02 - £17.02
£17.02
£17.02 - £17.02
£17.02
4tr28-pilot-bore-08b-1-2-pitch-sprocket

4TR28 (08B-3-28) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 28 Tooth

£15.78 - £15.78
£15.78
£15.78 - £15.78
£15.78

4TR28 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR28 Pitch 1/2 Teeth 28 Outside Dia (mm) 118 ...

View full details
£15.78 - £15.78
£15.78
£15.78 - £15.78
£15.78
4tr26-pilot-bore-08b-1-2-pitch-sprocket

4TR26 (08B-3-26) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 26 Tooth

£13.91 - £13.91
£13.91
£13.91 - £13.91
£13.91

4TR26 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR26 Pitch 1/2 Teeth 26 Outside Dia (mm) 110 ...

View full details
£13.91 - £13.91
£13.91
£13.91 - £13.91
£13.91
4tr25-pilot-bore-08b-1-2-pitch-sprocket

4TR25 (08B-3-25) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 25 Tooth

£12.82 - £12.82
£12.82
£12.82 - £12.82
£12.82

4TR25 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR25 Pitch 1/2 Teeth 25 Outside Dia (mm) 105.8 ...

View full details
£12.82 - £12.82
£12.82
£12.82 - £12.82
£12.82
4tr24-pilot-bore-08b-1-2-pitch-sprocket

4TR24 (08B-3-24) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 24 Tooth

£11.72 - £11.72
£11.72
£11.72 - £11.72
£11.72

4TR24 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR24 Pitch 1/2 Teeth 24 Outside Dia (mm) 101.8 ...

View full details
£11.72 - £11.72
£11.72
£11.72 - £11.72
£11.72
4tr23-pilot-bore-08b-1-2-pitch-sprocket

4TR23 (08B-3-23) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 23 Tooth

£10.69 - £10.69
£10.69
£10.69 - £10.69
£10.69

4TR23 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR23 Pitch 1/2 Teeth 23 Outside Dia (mm) 98.2 ...

View full details
£10.69 - £10.69
£10.69
£10.69 - £10.69
£10.69
4tr22-pilot-bore-08b-1-2-pitch-sprocket

4TR22 (08B-3-22) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 22 Tooth

£10.05 - £10.05
£10.05
£10.05 - £10.05
£10.05

4TR22 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR22 Pitch 1/2 Teeth 22 Outside Dia (mm) 93.8 ...

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£10.05 - £10.05
£10.05
£10.05 - £10.05
£10.05
4tr21-pilot-bore-08b-1-2-pitch-sprocket

4TR21 (08B-3-21) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 21 Tooth

£9.29 - £9.29
£9.29
£9.29 - £9.29
£9.29

4TR21 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR21 Pitch 1/2 Teeth 21 Outside Dia (mm) 89.7 ...

View full details
£9.29 - £9.29
£9.29
£9.29 - £9.29
£9.29
4tr20-pilot-bore-08b-1-2-pitch-sprocket

4TR20 (08B-3-20) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 20 Tooth

£7.97 - £7.97
£7.97
£7.97 - £7.97
£7.97

4TR20 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR20 Pitch 1/2 Teeth 20 Outside Dia (mm) 85.8 ...

View full details
£7.97 - £7.97
£7.97
£7.97 - £7.97
£7.97
4tr19-pilot-bore-08b-1-2-pitch-sprocket

4TR19 (08B-3-19) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 19 Tooth

£7.18 - £7.18
£7.18
£7.18 - £7.18
£7.18

4TR19 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR19 Pitch 1/2 Teeth 19 Outside Dia (mm) 81.7 ...

View full details
£7.18 - £7.18
£7.18
£7.18 - £7.18
£7.18
4tr18-pilot-bore-08b-1-2-pitch-sprocket

4TR18 (08B-3-18) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 18 Tooth

£6.59 - £6.59
£6.59
£6.59 - £6.59
£6.59

4TR18 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR18 Pitch 1/2 Teeth 18 Outside Dia (mm) 77.8 ...

View full details
£6.59 - £6.59
£6.59
£6.59 - £6.59
£6.59
4tr17-pilot-bore-08b-1-2-pitch-sprocket

4TR17 (08B-3-17) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 17 Tooth

£6.01 - £6.01
£6.01
£6.01 - £6.01
£6.01

4TR17 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR17 Pitch 1/2 Teeth 17 Outside Dia (mm) 73.6 ...

View full details
£6.01 - £6.01
£6.01
£6.01 - £6.01
£6.01
4tr16-pilot-bore-08b-1-2-pitch-sprocket

4TR16 (08B-3-16) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 16 Tooth

£6.30 - £6.30
£6.30
£6.30 - £6.30
£6.30

4TR16 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR16 Pitch 1/2 Teeth 16 Outside Dia (mm) 69.5 ...

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£6.30 - £6.30
£6.30
£6.30 - £6.30
£6.30
4tr15-pilot-bore-08b-1-2-pitch-sprocket

4TR15 (08B-3-15) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 15 Tooth

£5.89 - £5.89
£5.89
£5.89 - £5.89
£5.89

4TR15 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR15 Pitch 1/2 Teeth 15 Outside Dia (mm) 65.5 ...

View full details
£5.89 - £5.89
£5.89
£5.89 - £5.89
£5.89
4tr13-pilot-bore-08b-1-2-pitch-sprocket

4TR13 (08B-3-13) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 13 Tooth

£4.90 - £4.90
£4.90
£4.90 - £4.90
£4.90

4TR13 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR13 Pitch 1/2 Teeth 13 Outside Dia (mm) 57.4 ...

View full details
£4.90 - £4.90
£4.90
£4.90 - £4.90
£4.90
4tr12-pilot-bore-08b-1-2-pitch-sprocket

4TR12 (08B-3-12) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 12 Tooth

£4.30 - £4.30
£4.30
£4.30 - £4.30
£4.30

4TR12 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR12 Pitch 1/2 Teeth 12 Outside Dia (mm) 53 O...

View full details
£4.30 - £4.30
£4.30
£4.30 - £4.30
£4.30
4tr11-pilot-bore-08b-1-2-pitch-sprocket

4TR11 (08B-3-11) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 11 Tooth

£3.90 - £3.90
£3.90
£3.90 - £3.90
£3.90

4TR11 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR11 Pitch 1/2 Teeth 11 Outside Dia (mm) 48.7 ...

View full details
£3.90 - £3.90
£3.90
£3.90 - £3.90
£3.90
4tr10-pilot-bore-08b-1-2-pitch-sprocket

4TR10 (08B-3-10) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 10 Tooth

£3.35 - £3.35
£3.35
£3.35 - £3.35
£3.35

4TR10 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR10 Pitch 1/2 Teeth 10 Outside Dia (mm) 45.2 ...

View full details
£3.35 - £3.35
£3.35
£3.35 - £3.35
£3.35

Hi. Need any help?