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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.

4SR18 22mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 18 Tooth

£11.48 - £11.48
£11.48
£11.48 - £11.48
£11.48

Roller Chain Sprocket 08B 4SR18 22mm Bore Key & 2 Set Screws 1/2" Pitch 18 ToothChain Pitch:08B-1Number of Teeth:18Bore & Keyway(mm):22mmMf...

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£11.48 - £11.48
£11.48
£11.48 - £11.48
£11.48

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

£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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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£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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

£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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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£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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

£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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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£10.52 - £10.52
£10.52
£10.52 - £10.52
£10.52

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

£9.63 - £9.63
£9.63
£9.63 - £9.63
£9.63

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

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£9.63 - £9.63
£9.63
£9.63 - £9.63
£9.63

4SR15 14mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 15 Tooth

£9.63 - £9.63
£9.63
£9.63 - £9.63
£9.63

Roller Chain Sprocket 08B 4SR15 14mm Bore Key & 2 Set Screws 1/2" Pitch 15 ToothChain Pitch:08B-1Number of Teeth:15Bore & Keyway(mm):14mmMf...

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£9.63 - £9.63
£9.63
£9.63 - £9.63
£9.63

4SR14 15mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 14 Tooth

£9.35 - £9.35
£9.35
£9.35 - £9.35
£9.35

Roller Chain Sprocket 08B 4SR14 15mm Bore Key & 2 Set Screws 1/2" Pitch 14 ToothChain Pitch:08B-1Number of Teeth:14Bore & Keyway(mm):15mmMf...

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£9.35 - £9.35
£9.35
£9.35 - £9.35
£9.35

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

£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

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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£8.96 - £8.96
£8.96
£8.96 - £8.96
£8.96

4SR12 18mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 12 Tooth

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

Roller Chain Sprocket 08B 4SR12 18mm Bore Key & 2 Set Screws 1/2" Pitch 12 ToothChain Pitch:08B-1Number of Teeth:12Bore & Keyway(mm):18mmMf...

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£8.54 - £8.54
£8.54
£8.54 - £8.54
£8.54
4SR13-BS-Stainless-Steel-Simplex-Pilot-Bore-08B-1/2"-Pitch-Sprocket-13-Tooth

4SR13 (08B-1-13) - BS Stainless Steel Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 13 Tooth

£13.08 - £13.08
£13.08
£13.08 - £13.08
£13.08

4SR13 Stainless Steel Pilot Bore 08B 1/2" Pitch Sprocket   For use with 08B-1 Simplex Chain   Part Number 4SR13 Pitch 1/2 Teeth 13 Outside...

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£13.08 - £13.08
£13.08
£13.08 - £13.08
£13.08
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

£14.39 - £14.39
£14.39
£14.39 - £14.39
£14.39

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...

View full details
£14.39 - £14.39
£14.39
£14.39 - £14.39
£14.39
4SR15-BS-Stainless-Steel-Simplex-Pilot-Bore-08B-1/2"-Pitch-Sprocket-15-Tooth

4SR15 (08B-1-15) - BS Stainless Steel Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 15 Tooth

£15.37 - £15.37
£15.37
£15.37 - £15.37
£15.37

4SR15 Stainless Steel Pilot Bore 08B 1/2" Pitch Sprocket   For use with 08B-1 Simplex Chain   Part Number 4SR15 Pitch 1/2 Teeth 15 Outside...

View full details
£15.37 - £15.37
£15.37
£15.37 - £15.37
£15.37
4SR25-BS-Stainless-Steel-Simplex-Pilot-Bore-08B-1/2"-Pitch-Sprocket-25-Tooth

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

£29.07 - £29.07
£29.07
£29.07 - £29.07
£29.07

4SR25 Stainless Steel Pilot Bore 08B 1/2" Pitch Sprocket   For use with 08B-1 Simplex Chain   Part Number 4SR25 Pitch 1/2 Teeth 25 Outside...

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£29.07 - £29.07
£29.07
£29.07 - £29.07
£29.07
4tr14-pilot-bore-08b-1-2-pitch-sprocket

4TR14 (08B-3-14) - BS Triplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 14 Tooth

£5.48 - £5.48
£5.48
£5.48 - £5.48
£5.48

4TR14 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-3 Triplex Chain Part Number 4TR14 Pitch 1/2 Teeth 14 Outside Dia (mm) 61.8 ...

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£5.48 - £5.48
£5.48
£5.48 - £5.48
£5.48
4dr21-pilot-bore-08b-1-2-pitch-sprocket

4DR21 (08B-2-21) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 21 Tooth

£6.97 - £6.97
£6.97
£6.97 - £6.97
£6.97

4DR21 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR21 Pitch 1/2 Teeth 21 Outside Dia (mm) 89.7 ...

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£6.97 - £6.97
£6.97
£6.97 - £6.97
£6.97
4dr20-pilot-bore-08b-1-2-pitch-sprocket

4DR20 (08B-2-20) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 20 Tooth

£5.76 - £5.76
£5.76
£5.76 - £5.76
£5.76

4DR20 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR20 Pitch 1/2 Teeth 20 Outside Dia (mm) 85.8 ...

View full details
£5.76 - £5.76
£5.76
£5.76 - £5.76
£5.76
4dr19-pilot-bore-08b-1-2-pitch-sprocket

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

£5.76 - £5.76
£5.76
£5.76 - £5.76
£5.76

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 ...

View full details
£5.76 - £5.76
£5.76
£5.76 - £5.76
£5.76
4dr14-pilot-bore-08b-1-2-pitch-sprocket

4DR14 (08B-2-14) - BS Duplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 14 Tooth

£4.01 - £4.01
£4.01
£4.01 - £4.01
£4.01

4DR14 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-2 Duplex Chain Part Number 4DR14 Pitch 1/2 Teeth 14 Outside Dia (mm) 61.8 ...

View full details
£4.01 - £4.01
£4.01
£4.01 - £4.01
£4.01
4dr13-pilot-bore-08b-1-2-pitch-sprocket

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

£3.51 - £3.51
£3.51
£3.51 - £3.51
£3.51

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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£3.51 - £3.51
£3.51
£3.51 - £3.51
£3.51
4dr11-pilot-bore-08b-1-2-pitch-sprocket

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

£2.70 - £2.70
£2.70
£2.70 - £2.70
£2.70

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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£2.70 - £2.70
£2.70
£2.70 - £2.70
£2.70
4dr10-pilot-bore-08b-1-2-pitch-sprocket

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

£2.53 - £2.53
£2.53
£2.53 - £2.53
£2.53

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 ...

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£2.53 - £2.53
£2.53
£2.53 - £2.53
£2.53
4sr45-pilot-bore-08b-1-2-pitch-sprocket

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

£13.27 - £13.27
£13.27
£13.27 - £13.27
£13.27

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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£13.27 - £13.27
£13.27
£13.27 - £13.27
£13.27
4sr35-pilot-bore-08b-1-2-pitch-sprocket

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

£8.81 - £8.81
£8.81
£8.81 - £8.81
£8.81

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
£8.81 - £8.81
£8.81
£8.81 - £8.81
£8.81
4sr26-pilot-bore-08b-1-2-pitch-sprocket

4SR26 (08B-1-26) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 26 Tooth

£4.99 - £4.99
£4.99
£4.99 - £4.99
£4.99

4SR26 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR26 Pitch 1/2 Teeth 26 Outside Dia (mm) 110 ...

View full details
£4.99 - £4.99
£4.99
£4.99 - £4.99
£4.99

Hi. Need any help?