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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.

4dr13-pilot-bore-08b-1-2-pitch-sprocket

4DR13 (08B-2-13) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 13 Tooth

£3.63 - £3.63
£3.63
£3.63 - £3.63
£3.63

4DR13 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR13 Pitch 1/2 Teeth 13 Outside Dia (mm) 57.4 ...

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£3.63 - £3.63
£3.63
£3.63 - £3.63
£3.63
4dr11-pilot-bore-08b-1-2-pitch-sprocket

4DR11 (08B-2-11) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 11 Tooth

£2.79 - £2.79
£2.79
£2.79 - £2.79
£2.79

4DR11 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR11 Pitch 1/2 Teeth 11 Outside Dia (mm) 48.7 ...

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£2.79 - £2.79
£2.79
£2.79 - £2.79
£2.79
4dr09-pilot-bore-08b-1-2-pitch-sprocket

4DR09 (08B-2-09) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 9 Tooth

£2.43 - £2.43
£2.43
£2.43 - £2.43
£2.43

4DR09 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR09 Pitch 1/2 Teeth 9 Outside Dia (mm) 41 Ove...

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£2.43 - £2.43
£2.43
£2.43 - £2.43
£2.43
4sr45-pilot-bore-08b-1-2-pitch-sprocket

4SR45 (08B-1-45) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 45 Tooth

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

4SR45 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR45 Pitch 1/2 Teeth 45 Outside Dia (mm) 188 ...

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£13.74 - £13.74
£13.74
£13.74 - £13.74
£13.74
4sr17-pilot-bore-08b-1-2-pitch-sprocket

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

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

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 ...

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

4SR30 35mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 30 Tooth

£22.91 - £22.91
£22.91
£22.91 - £22.91
£22.91

Roller Chain Sprocket 08B 4SR30 35mm Bore Key & 2 Set Screws 1/2" Pitch 30 ToothChain Pitch:08B-1Number of Teeth:30Bore & Keyway(mm):35mmMf...

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£22.91 - £22.91
£22.91
£22.91 - £22.91
£22.91

4SR25 32mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 25 Tooth

£17.67 - £17.67
£17.67
£17.67 - £17.67
£17.67

Roller Chain Sprocket 08B 4SR25 32mm Bore Key & 2 Set Screws 1/2" Pitch 25 ToothChain Pitch:08B-1Number of Teeth:25Bore & Keyway(mm):32mmMf...

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£17.67 - £17.67
£17.67
£17.67 - £17.67
£17.67

4SR24 24mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 24 Tooth

£16.61 - £16.61
£16.61
£16.61 - £16.61
£16.61

Roller Chain Sprocket 08B 4SR24 24mm Bore Key & 2 Set Screws 1/2" Pitch 24 ToothChain Pitch:08B-1Number of Teeth:24Bore & Keyway(mm):24mmMf...

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£16.61 - £16.61
£16.61
£16.61 - £16.61
£16.61

4SR23 30mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 23 Tooth

£15.85 - £15.85
£15.85
£15.85 - £15.85
£15.85

Roller Chain Sprocket 08B 4SR23 30mm Bore Key & 2 Set Screws 1/2" Pitch 23 ToothChain Pitch:08B-1Number of Teeth:23Bore & Keyway(mm):30mmMf...

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£15.85 - £15.85
£15.85
£15.85 - £15.85
£15.85

4SR21 30mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 21 Tooth

£14.28 - £14.28
£14.28
£14.28 - £14.28
£14.28

Roller Chain Sprocket 08B 4SR21 30mm Bore Key & 2 Set Screws 1/2" Pitch 21 ToothChain Pitch:08B-1Number of Teeth:21Bore & Keyway(mm):30mmMf...

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£14.28 - £14.28
£14.28
£14.28 - £14.28
£14.28

4SR21 20mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 21 Tooth

£14.28 - £14.28
£14.28
£14.28 - £14.28
£14.28

Roller Chain Sprocket 08B 4SR21 20mm Bore Key & 2 Set Screws 1/2" Pitch 21 ToothChain Pitch:08B-1Number of Teeth:21Bore & Keyway(mm):20mmMf...

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£14.28 - £14.28
£14.28
£14.28 - £14.28
£14.28

4SR19 25mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 19 Tooth

£12.87 - £12.87
£12.87
£12.87 - £12.87
£12.87

Roller Chain Sprocket 08B 4SR19 25mm Bore Key & 2 Set Screws 1/2" Pitch 19 ToothChain Pitch:08B-1Number of Teeth:19Bore & Keyway(mm):25mmMf...

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£12.87 - £12.87
£12.87
£12.87 - £12.87
£12.87

4SR19 22mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 19 Tooth

£12.87 - £12.87
£12.87
£12.87 - £12.87
£12.87

Roller Chain Sprocket 08B 4SR19 22mm Bore Key & 2 Set Screws 1/2" Pitch 19 ToothChain Pitch:08B-1Number of Teeth:19Bore & Keyway(mm):22mmMf...

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£12.87 - £12.87
£12.87
£12.87 - £12.87
£12.87

4SR18 25mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 18 Tooth

£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

Roller Chain Sprocket 08B 4SR18 25mm Bore Key & 2 Set Screws 1/2" Pitch 18 ToothChain Pitch:08B-1Number of Teeth:18Bore & Keyway(mm):25mmMf...

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£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

4SR18 19mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 18 Tooth

£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

Roller Chain Sprocket 08B 4SR18 19mm Bore Key & 2 Set Screws 1/2" Pitch 18 ToothChain Pitch:08B-1Number of Teeth:18Bore & Keyway(mm):19mmMf...

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£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

4SR18 16mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 18 Tooth

£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

Roller Chain Sprocket 08B 4SR18 16mm Bore Key & 2 Set Screws 1/2" Pitch 18 ToothChain Pitch:08B-1Number of Teeth:18Bore & Keyway(mm):16mmMf...

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£11.88 - £11.88
£11.88
£11.88 - £11.88
£11.88

4SR16 28mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 16 Tooth

£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

Roller Chain Sprocket 08B 4SR16 28mm Bore Key & 2 Set Screws 1/2" Pitch 16 ToothChain Pitch:08B-1Number of Teeth:16Bore & Keyway(mm):28mmMf...

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£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

4SR16 24mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 16 Tooth

£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

Roller Chain Sprocket 08B 4SR16 24mm Bore Key & 2 Set Screws 1/2" Pitch 16 ToothChain Pitch:08B-1Number of Teeth:16Bore & Keyway(mm):24mmMf...

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£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

4SR16 22mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 16 Tooth

£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

Roller Chain Sprocket 08B 4SR16 22mm Bore Key & 2 Set Screws 1/2" Pitch 16 ToothChain Pitch:08B-1Number of Teeth:16Bore & Keyway(mm):22mmMf...

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£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

4SR16 16mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 16 Tooth

£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

Roller Chain Sprocket 08B 4SR16 16mm Bore Key & 2 Set Screws 1/2" Pitch 16 ToothChain Pitch:08B-1Number of Teeth:16Bore & Keyway(mm):16mmMf...

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£10.89 - £10.89
£10.89
£10.89 - £10.89
£10.89

4SR15 28mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 15 Tooth

£9.98 - £9.98
£9.98
£9.98 - £9.98
£9.98

Roller Chain Sprocket 08B 4SR15 28mm Bore Key & 2 Set Screws 1/2" Pitch 15 ToothChain Pitch:08B-1Number of Teeth:15Bore & Keyway(mm):28mmMf...

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£9.98 - £9.98
£9.98
£9.98 - £9.98
£9.98

4SR15 20mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 15 Tooth

£9.98 - £9.98
£9.98
£9.98 - £9.98
£9.98

Roller Chain Sprocket 08B 4SR15 20mm Bore Key & 2 Set Screws 1/2" Pitch 15 ToothChain Pitch:08B-1Number of Teeth:15Bore & Keyway(mm):20mmMf...

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£9.98 - £9.98
£9.98
£9.98 - £9.98
£9.98

4SR14 18mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 14 Tooth

£9.68 - £9.68
£9.68
£9.68 - £9.68
£9.68

Roller Chain Sprocket 08B 4SR14 18mm Bore Key & 2 Set Screws 1/2" Pitch 14 ToothChain Pitch:08B-1Number of Teeth:14Bore & Keyway(mm):18mmMf...

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£9.68 - £9.68
£9.68
£9.68 - £9.68
£9.68

4SR14 16mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 14 Tooth

£9.68 - £9.68
£9.68
£9.68 - £9.68
£9.68

Roller Chain Sprocket 08B 4SR14 16mm Bore Key & 2 Set Screws 1/2" Pitch 14 ToothChain Pitch:08B-1Number of Teeth:14Bore & Keyway(mm):16mmMf...

View full details
£9.68 - £9.68
£9.68
£9.68 - £9.68
£9.68

Hi. Need any help?