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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 28mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 13 Tooth

£10.57 - £10.57
£10.57
£10.57 - £10.57
£10.57

Roller Chain Sprocket 08B 4SR13 28mm Bore Key & 2 Set Screws 1/2" Pitch 13 ToothChain Pitch:08B-1Number of Teeth:13Bore & Keyway(mm):28mmMf...

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£10.57 - £10.57
£10.57
£10.57 - £10.57
£10.57

4SR13 22mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 13 Tooth

£9.27 - £9.27
£9.27
£9.27 - £9.27
£9.27

Roller Chain Sprocket 08B 4SR13 22mm Bore Key & 2 Set Screws 1/2" Pitch 13 ToothChain Pitch:08B-1Number of Teeth:13Bore & Keyway(mm):22mmMf...

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£9.27 - £9.27
£9.27
£9.27 - £9.27
£9.27

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

£9.27 - £9.27
£9.27
£9.27 - £9.27
£9.27

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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£9.27 - £9.27
£9.27
£9.27 - £9.27
£9.27

4SR12 14mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 12 Tooth

£8.84 - £8.84
£8.84
£8.84 - £8.84
£8.84

Roller Chain Sprocket 08B 4SR12 14mm Bore Key & 2 Set Screws 1/2" Pitch 12 ToothChain Pitch:08B-1Number of Teeth:12Bore & Keyway(mm):14mmMf...

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£8.84 - £8.84
£8.84
£8.84 - £8.84
£8.84
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

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

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

£15.72 - £15.72
£15.72
£15.72 - £15.72
£15.72

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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£15.72 - £15.72
£15.72
£15.72 - £15.72
£15.72
4tr27-pilot-bore-08b-1-2-pitch-sprocket

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

£14.62 - £14.62
£14.62
£14.62 - £14.62
£14.62

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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£14.62 - £14.62
£14.62
£14.62 - £14.62
£14.62
4dr57-pilot-bore-08b-1-2-pitch-sprocket

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

£40.28 - £40.28
£40.28
£40.28 - £40.28
£40.28

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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£40.28 - £40.28
£40.28
£40.28 - £40.28
£40.28
4dr40-pilot-bore-08b-1-2-pitch-sprocket

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

£21.28 - £21.28
£21.28
£21.28 - £21.28
£21.28

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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£21.28 - £21.28
£21.28
£21.28 - £21.28
£21.28
4dr38-pilot-bore-08b-1-2-pitch-sprocket

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

£19.81 - £19.81
£19.81
£19.81 - £19.81
£19.81

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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£19.81 - £19.81
£19.81
£19.81 - £19.81
£19.81
4dr36-pilot-bore-08b-1-2-pitch-sprocket

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

£18.40 - £18.40
£18.40
£18.40 - £18.40
£18.40

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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£18.40 - £18.40
£18.40
£18.40 - £18.40
£18.40
4dr23-pilot-bore-08b-1-2-pitch-sprocket

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

£7.66 - £7.66
£7.66
£7.66 - £7.66
£7.66

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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£7.66 - £7.66
£7.66
£7.66 - £7.66
£7.66
4dr19-pilot-bore-08b-1-2-pitch-sprocket

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

£5.97 - £5.97
£5.97
£5.97 - £5.97
£5.97

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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£5.97 - £5.97
£5.97
£5.97 - £5.97
£5.97
4dr10-pilot-bore-08b-1-2-pitch-sprocket

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

£2.62 - £2.62
£2.62
£2.62 - £2.62
£2.62

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 ...

View full details
£2.62 - £2.62
£2.62
£2.62 - £2.62
£2.62
4sr40-pilot-bore-08b-1-2-pitch-sprocket

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

£10.91 - £10.91
£10.91
£10.91 - £10.91
£10.91

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 ...

View full details
£10.91 - £10.91
£10.91
£10.91 - £10.91
£10.91
4sr35-pilot-bore-08b-1-2-pitch-sprocket

4SR35 (08B-1-35) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 35 Tooth

£9.12 - £9.12
£9.12
£9.12 - £9.12
£9.12

4SR35 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR35 Pitch 1/2 Teeth 35 Outside Dia (mm) 14.7 ...

View full details
£9.12 - £9.12
£9.12
£9.12 - £9.12
£9.12
4sr31-pilot-bore-08b-1-2-pitch-sprocket

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

£8.13 - £8.13
£8.13
£8.13 - £8.13
£8.13

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 ...

View full details
£8.13 - £8.13
£8.13
£8.13 - £8.13
£8.13
4sr25-pilot-bore-08b-1-2-pitch-sprocket

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

£6.07 - £6.07
£6.07
£6.07 - £6.07
£6.07

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
£6.07 - £6.07
£6.07
£6.07 - £6.07
£6.07
4sr24-pilot-bore-08b-1-2-pitch-sprocket

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

£5.84 - £5.84
£5.84
£5.84 - £5.84
£5.84

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
£5.84 - £5.84
£5.84
£5.84 - £5.84
£5.84
4sr38-pilot-bore-08b-1-2-pitch-sprocket

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

£21.00 - £21.00
£21.00
£21.00 - £21.00
£21.00

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

£21.00 - £21.00
£21.00
£21.00 - £21.00
£21.00
4sr45-pilot-bore-08b-1-2-pitch-sprocket

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

£26.53 - £26.53
£26.53
£26.53 - £26.53
£26.53

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

£26.53 - £26.53
£26.53
£26.53 - £26.53
£26.53
4sr57-pilot-bore-08b-1-2-pitch-sprocket

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

£32.02 - £32.02
£32.02
£32.02 - £32.02
£32.02

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

£32.02 - £32.02
£32.02
£32.02 - £32.02
£32.02
4sr76-pilot-bore-08b-1-2-pitch-sprocket

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

£47.72 - £47.72
£47.72
£47.72 - £47.72
£47.72

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

£47.72 - £47.72
£47.72
£47.72 - £47.72
£47.72
4sr95-pilot-bore-08b-1-2-pitch-sprocket

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

£79.27 - £79.27
£79.27
£79.27 - £79.27
£79.27

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

£79.27 - £79.27
£79.27
£79.27 - £79.27
£79.27

Hi. Need any help?