Biloc Pulleys: Making Pulley Installation Easy
Pilot bore and taper lock pulleys are still widely used, but many applications need easy installation, better shaft protection, easier maintenance, and greater flexibility.
Biloc pulleys, also known as Miloc, Mi-Lock, Bifit and Bi-lock, offer a practical alternative to conventional pulley systems by removing keyways, reducing installation time, and simplifying maintenance. RR Fisher supplies Biloc pulleys right throughout New Zealand to a wide range of users.
What Is a Biloc Pulley?
A Biloc pulley is a keyless pulley system that uses a precision locking bush to create a high-strength friction connection between the pulley and shaft.
Unlike traditional pilot bore pulleys that require machining, or taper lock pulleys that rely on keyed connections, Biloc systems use a mechanical locking assembly that grips the shaft uniformly around its entire circumference.
The result is:
- No keyways
- No reboring
- No shaft weakening
- No backlash
- Faster installation
- Greater flexibility
Biloc pulleys are supplied as finished components and can be fitted to a wide range of shaft sizes simply by selecting the appropriate locking bush. A particularly useful feature is the ability to mount two pulleys of different diameters on a single bush assembly, making Biloc ideal for variable-speed machinery and retrofit applications.
Traditional Pulley Options
Pilot bore pulleys are supplied with an unfinished bore and usually need machining, keyway cutting, and additional fitting work before installation.
That adds time, cost, and complexity, especially when different shaft sizes require different pulley setups.
Taper lock pulleys improve on pilot bore designs with interchangeable bushes and easier installation, but they still usually rely on keyways and localised shaft loading.
Why Biloc Pulleys Are Better
1. No keyways, less shaft stress
One of the biggest advantages of Biloc pulleys is that they eliminate the need for keyways. That helps preserve shaft strength, reduce stress concentrations, and improve long-term reliability.
2. Better grip and torque transmission
Biloc locking assemblies grip around the full shaft circumference rather than transmitting load through a small key. That improves load distribution, reduces movement under shock loads, and supports strong torque transmission.
3. Faster installation and easier maintenance
Because Biloc pulleys do not need machining, keyway alignment, or the same level of fitting work as traditional options, they are quicker to install and easier to remove later for maintenance.
4. More flexibility in positioning and stockholding
Biloc systems allow precise axial positioning and easy repositioning, which helps with belt alignment and makes them useful for conveyor systems, pumps, fans, packaging equipment, and multi-speed drives.
They can also reduce inventory requirements because a smaller pulley and bush range can cover a broader spread of shaft sizes.
5. Good dynamic performance and multi-speed capability
Biloc pulleys centre accurately on the shaft, which can help improve concentricity, reduce vibration, and support smoother running. They are also well suited to multi-speed drive arrangements where two pulleys of different diameters may need to be mounted on one bush assembly.
Biloc vs Cast Iron Pilot Bore vs Taper Lock
|
Feature |
Pilot Bore |
Taper Lock |
Biloc |
|
Requires machining |
Yes |
No |
No |
|
Requires keyway |
Yes |
Usually Yes |
No |
|
Shaft weakening |
High |
Moderate |
None |
|
Installation speed |
Slow |
Medium |
Fast |
|
Repositioning |
Difficult |
Moderate |
Easy |
|
Torque transmission |
Good |
Very Good |
Excellent |
|
Inventory flexibility |
Poor |
Good |
Excellent |
|
Maintenance removal |
Difficult |
Moderate |
Easy |
|
Multi-speed applications |
Limited |
Good |
Excellent |
|
Shaft protection |
Poor |
Good |
Excellent |
Typical Applications
Biloc pulleys are commonly used in:
- Manufacturing plants
- Food processing
- Packaging machinery
- Agricultural equipment
- Pumps
- Compressors
- HVAC systems
- Conveyor systems
- Quarry and mining equipment
- Multi-speed drive systems
Where downtime is expensive, the advantages become even more significant.
Biloc Pulley Sizes
|
Code |
Pitch A Dia (mm) |
Pitch B Dia (mm) |
Outside Dia (mm) |
Weight (kg) |
Bush Size |
|
71 |
81 |
88 |
0.42 |
No. 1 |
|
|
75 |
85 |
92 |
0.47 |
No. 1 |
|
|
80 |
90 |
97 |
0.53 |
No. 1 |
|
|
85 |
95 |
102 |
0.62 |
No. 1 |
|
|
90 |
100 |
107 |
0.72 |
No. 1 |
|
|
95 |
105 |
111 |
0.8 |
No. 1 |
|
|
100 |
110 |
117 |
0.91 |
No. 1 |
|
|
106 |
116 |
123 |
1.02 |
No. 1 |
|
|
112 |
122 |
129 |
0.98 |
No. 1 |
|
|
118 |
128 |
135 |
1.05 |
No. 1 |
|
|
125 |
135 |
142 |
1.17 |
No. 1 |
|
|
132 |
142 |
149 |
1.28 |
No. 1 |
|
|
140 |
150 |
157 |
1.49 |
No. 2 |
|
|
150 |
160 |
167 |
1.61 |
No. 2 |
|
|
160 |
170 |
177 |
1.75 |
No. 2 |
|
|
180 |
190 |
197 |
2.03 |
No. 2 |
|
|
200 |
209 |
216 |
2.38 |
No. 2 |
|
|
224 |
233 |
240 |
3.34 |
No. 2 |
|
|
250 |
259 |
266 |
4.22 |
No. 2 |
|
|
280 |
289 |
296 |
4.34 |
No. 2 |
|
|
315 |
324 |
331 |
4.45 |
No. 2 |
|
|
355 |
264 |
371 |
4.94 |
No. 2 |
|
|
400 |
409 |
416 |
7.51 |
No. 2 |
|
|
450 |
459 |
466 |
9.05 |
No. 2 |
Conclusion
Biloc pulleys offer a simpler, more flexible alternative to both pilot bore and taper lock systems. They remove keyways, reduce fitting time, protect the shaft, and make maintenance easier, while also supporting strong torque transmission and flexible positioning.
For applications where downtime, reliability, and ease of maintenance matter, Biloc can offer a clear practical advantage. RR Fisher dispatches Biloc Pulleys the same day for overnight delivery to Whangarei, Auckland, Hamilton, Tauranga, Rotorua, Taupo, New Plymouth, Gisborne, Palmerston North, Wellington, Nelson, Christchurch, Dunedin and Invercargill.