Skip to content
We are Open 9am - 4pm GMT
We are Open 9am - 4pm GMT
FREE UK DELIVERY OVER £100
LOW COST WORLDWIDE DISTRIBUTION
NEXT / SAME DAY DELIVERY AVAILABLE
NEED HELP? EMAIL US....

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.

4dr14-pilot-bore-08b-1-2-pitch-sprocket

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

£4.44 - £4.44
£4.44
£4.44 - £4.44
£4.44

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
£4.44 - £4.44
£4.44
£4.44 - £4.44
£4.44
4dr13-pilot-bore-08b-1-2-pitch-sprocket

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

£3.89 - £3.89
£3.89
£3.89 - £3.89
£3.89

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 ...

View full details
£3.89 - £3.89
£3.89
£3.89 - £3.89
£3.89
4dr11-pilot-bore-08b-1-2-pitch-sprocket

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

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

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 ...

View full details
£3.00 - £3.00
£3.00
£3.00 - £3.00
£3.00
4dr09-pilot-bore-08b-1-2-pitch-sprocket

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

£2.60 - £2.60
£2.60
£2.60 - £2.60
£2.60

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...

View full details
£2.60 - £2.60
£2.60
£2.60 - £2.60
£2.60
4sr45-pilot-bore-08b-1-2-pitch-sprocket

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

£14.73 - £14.73
£14.73
£14.73 - £14.73
£14.73

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 ...

View full details
£14.73 - £14.73
£14.73
£14.73 - £14.73
£14.73
4sr38-pilot-bore-08b-1-2-pitch-sprocket

4SR38 (08B-1-38) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 38 Tooth

£11.06 - £11.06
£11.06
£11.06 - £11.06
£11.06

4SR38 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR38 Pitch 1/2 Teeth 38 Outside Dia (mm) 158.6 ...

View full details
£11.06 - £11.06
£11.06
£11.06 - £11.06
£11.06
4sr08-pilot-bore-08b-1-2-pitch-sprocket

4SR08 (08B-1-08) - BS Simplex Roller Chain Sprocket Pilot Bore 08B 1/2" - 8 Tooth

£1.00 - £1.00
£1.00
£1.00 - £1.00
£1.00

4SR08 Pilot Bore 08B 1/2" Pitch Sprocket For use with 08B-1 Simplex Chain Part Number 4SR08 Pitch 1/2 Teeth 8 Outside Dia (mm) 37.2 ...

View full details
£1.00 - £1.00
£1.00
£1.00 - £1.00
£1.00

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

£24.56 - £24.56
£24.56
£24.56 - £24.56
£24.56

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...

View full details
£24.56 - £24.56
£24.56
£24.56 - £24.56
£24.56

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

£18.94 - £18.94
£18.94
£18.94 - £18.94
£18.94

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...

View full details
£18.94 - £18.94
£18.94
£18.94 - £18.94
£18.94

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

£16.98 - £16.98
£16.98
£16.98 - £16.98
£16.98

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...

View full details
£16.98 - £16.98
£16.98
£16.98 - £16.98
£16.98

4SR20 25mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 20 Tooth

£14.55 - £14.55
£14.55
£14.55 - £14.55
£14.55

Roller Chain Sprocket 08B 4SR20 25mm Bore Key & 2 Set Screws 1/2" Pitch 20 ToothChain Pitch:08B-1Number of Teeth:20Bore & Keyway(mm):25mmMf...

View full details
£14.55 - £14.55
£14.55
£14.55 - £14.55
£14.55

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

£13.79 - £13.79
£13.79
£13.79 - £13.79
£13.79

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...

View full details
£13.79 - £13.79
£13.79
£13.79 - £13.79
£13.79

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

£13.79 - £13.79
£13.79
£13.79 - £13.79
£13.79

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...

View full details
£13.79 - £13.79
£13.79
£13.79 - £13.79
£13.79

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

£12.73 - £12.73
£12.73
£12.73 - £12.73
£12.73

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...

View full details
£12.73 - £12.73
£12.73
£12.73 - £12.73
£12.73

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

£12.73 - £12.73
£12.73
£12.73 - £12.73
£12.73

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...

View full details
£12.73 - £12.73
£12.73
£12.73 - £12.73
£12.73

4SR17 25mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 17 Tooth

£12.06 - £12.06
£12.06
£12.06 - £12.06
£12.06

Roller Chain Sprocket 08B 4SR17 25mm Bore Key & 2 Set Screws 1/2" Pitch 17 ToothChain Pitch:08B-1Number of Teeth:17Bore & Keyway(mm):25mmMf...

View full details
£12.06 - £12.06
£12.06
£12.06 - £12.06
£12.06

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

£11.67 - £11.67
£11.67
£11.67 - £11.67
£11.67

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...

View full details
£11.67 - £11.67
£11.67
£11.67 - £11.67
£11.67

4SR15 25mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 15 Tooth

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

Roller Chain Sprocket 08B 4SR15 25mm Bore Key & 2 Set Screws 1/2" Pitch 15 ToothChain Pitch:08B-1Number of Teeth:15Bore & Keyway(mm):25mmMf...

View full details
£10.69 - £10.69
£10.69
£10.69 - £10.69
£10.69

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

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

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...

View full details
£10.69 - £10.69
£10.69
£10.69 - £10.69
£10.69

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

£10.38 - £10.38
£10.38
£10.38 - £10.38
£10.38

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...

View full details
£10.38 - £10.38
£10.38
£10.38 - £10.38
£10.38

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

£10.38 - £10.38
£10.38
£10.38 - £10.38
£10.38

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
£10.38 - £10.38
£10.38
£10.38 - £10.38
£10.38

4SR13 28mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 13 Tooth

£11.34 - £11.34
£11.34
£11.34 - £11.34
£11.34

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...

View full details
£11.34 - £11.34
£11.34
£11.34 - £11.34
£11.34

4SR12 20mm Bore, Keyway & Grub Screws Roller Chain Sprocket 1/2" Pitch 12 Tooth

£9.48 - £9.48
£9.48
£9.48 - £9.48
£9.48

Roller Chain Sprocket 08B 4SR12 20mm Bore Key & 2 Set Screws 1/2" Pitch 12 ToothChain Pitch:08B-1Number of Teeth:12Bore & Keyway(mm):20mmMf...

View full details
£9.48 - £9.48
£9.48
£9.48 - £9.48
£9.48

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

£9.48 - £9.48
£9.48
£9.48 - £9.48
£9.48

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...

View full details
£9.48 - £9.48
£9.48
£9.48 - £9.48
£9.48

Hi. Need any help?