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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.

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

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

£21.57 - £21.57
£21.57
£21.57 - £21.57
£21.57

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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£21.57 - £21.57
£21.57
£21.57 - £21.57
£21.57
4tr30-pilot-bore-08b-1-2-pitch-sprocket

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

£19.68 - £19.68
£19.68
£19.68 - £19.68
£19.68

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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£19.68 - £19.68
£19.68
£19.68 - £19.68
£19.68
4tr29-pilot-bore-08b-1-2-pitch-sprocket

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

£18.24 - £18.24
£18.24
£18.24 - £18.24
£18.24

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 ...

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£18.24 - £18.24
£18.24
£18.24 - £18.24
£18.24
4tr28-pilot-bore-08b-1-2-pitch-sprocket

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

£16.91 - £16.91
£16.91
£16.91 - £16.91
£16.91

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 ...

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£16.91 - £16.91
£16.91
£16.91 - £16.91
£16.91
4tr26-pilot-bore-08b-1-2-pitch-sprocket

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

£14.90 - £14.90
£14.90
£14.90 - £14.90
£14.90

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
£14.90 - £14.90
£14.90
£14.90 - £14.90
£14.90
4tr25-pilot-bore-08b-1-2-pitch-sprocket

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

£13.74 - £13.74
£13.74
£13.74 - £13.74
£13.74

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 ...

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£13.74 - £13.74
£13.74
£13.74 - £13.74
£13.74
4tr24-pilot-bore-08b-1-2-pitch-sprocket

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

£12.57 - £12.57
£12.57
£12.57 - £12.57
£12.57

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
£12.57 - £12.57
£12.57
£12.57 - £12.57
£12.57
4tr23-pilot-bore-08b-1-2-pitch-sprocket

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

£11.46 - £11.46
£11.46
£11.46 - £11.46
£11.46

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
£11.46 - £11.46
£11.46
£11.46 - £11.46
£11.46
4tr22-pilot-bore-08b-1-2-pitch-sprocket

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

£10.77 - £10.77
£10.77
£10.77 - £10.77
£10.77

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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£10.77 - £10.77
£10.77
£10.77 - £10.77
£10.77
4tr21-pilot-bore-08b-1-2-pitch-sprocket

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

£9.95 - £9.95
£9.95
£9.95 - £9.95
£9.95

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 ...

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£9.95 - £9.95
£9.95
£9.95 - £9.95
£9.95
4tr20-pilot-bore-08b-1-2-pitch-sprocket

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

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

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
£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54
4tr19-pilot-bore-08b-1-2-pitch-sprocket

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

£7.69 - £7.69
£7.69
£7.69 - £7.69
£7.69

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
£7.69 - £7.69
£7.69
£7.69 - £7.69
£7.69
4tr18-pilot-bore-08b-1-2-pitch-sprocket

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

£7.07 - £7.07
£7.07
£7.07 - £7.07
£7.07

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 ...

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£7.07 - £7.07
£7.07
£7.07 - £7.07
£7.07
4tr17-pilot-bore-08b-1-2-pitch-sprocket

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

£6.44 - £6.44
£6.44
£6.44 - £6.44
£6.44

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 ...

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£6.44 - £6.44
£6.44
£6.44 - £6.44
£6.44
4tr16-pilot-bore-08b-1-2-pitch-sprocket

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

£6.75 - £6.75
£6.75
£6.75 - £6.75
£6.75

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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£6.75 - £6.75
£6.75
£6.75 - £6.75
£6.75
4tr15-pilot-bore-08b-1-2-pitch-sprocket

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

£6.31 - £6.31
£6.31
£6.31 - £6.31
£6.31

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
£6.31 - £6.31
£6.31
£6.31 - £6.31
£6.31
4tr13-pilot-bore-08b-1-2-pitch-sprocket

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

£5.25 - £5.25
£5.25
£5.25 - £5.25
£5.25

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
£5.25 - £5.25
£5.25
£5.25 - £5.25
£5.25
4tr12-pilot-bore-08b-1-2-pitch-sprocket

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

£4.60 - £4.60
£4.60
£4.60 - £4.60
£4.60

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
£4.60 - £4.60
£4.60
£4.60 - £4.60
£4.60
4tr11-pilot-bore-08b-1-2-pitch-sprocket

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

£4.18 - £4.18
£4.18
£4.18 - £4.18
£4.18

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 ...

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£4.18 - £4.18
£4.18
£4.18 - £4.18
£4.18
4tr10-pilot-bore-08b-1-2-pitch-sprocket

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

£3.58 - £3.58
£3.58
£3.58 - £3.58
£3.58

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
£3.58 - £3.58
£3.58
£3.58 - £3.58
£3.58
4tr09-pilot-bore-08b-1-2-pitch-sprocket

4TR09 (08B-3-09) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 9 Tooth

£3.00 - £3.00
£3.00
£3.00 - £3.00
£3.00

4TR09 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR09 Pitch 1/2 Teeth 09 Outside Dia (mm) 41 O...

View full details
£3.00 - £3.00
£3.00
£3.00 - £3.00
£3.00
4tr08-pilot-bore-08b-1-2-pitch-sprocket

4TR08 (08B-3-08) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 8 Tooth

£2.76 - £2.76
£2.76
£2.76 - £2.76
£2.76

4TR08 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR08 Pitch 1/2 Teeth 08 Outside Dia (mm) 37.2...

View full details
£2.76 - £2.76
£2.76
£2.76 - £2.76
£2.76
4dr95-pilot-bore-08b-1-2-pitch-sprocket

4DR95 (08B-2-95) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 95 Tooth

£108.88 - £108.88
£108.88
£108.88 - £108.88
£108.88

4DR95 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR95 Pitch 1/2 Teeth 95 Outside Dia (mm) 390.1 ...

View full details
£108.88 - £108.88
£108.88
£108.88 - £108.88
£108.88
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 ...

View full details
£72.80 - £72.80
£72.80
£72.80 - £72.80
£72.80

Hi. Need any help?