BN Rings
BN style rings have a free-state diameter smaller than the shaft diameter over which they are to be installed, so that when mounted to the shaft the rings conform to and become self-retaining on the shaft. If used with the centered or half-centered arrangement, the ring will snap into the groove and no further handling of the ring is necessary. If used with the free arrangement, the ring must be axially supported during assembly of the mating parts.
The BN ring is cut to fit inside a nominal circumference. Examples for use of the BN ring include mounting a bearing inner race to a shaft, or assemblies in which modification of the shaft is more practical than modifying the bore of the outer member.
Typical Applications for BN Rings
TORQUE TRANSFER
Tolerance rings often mount ball bearing outer races to retain the bearing in thermal growth applications. Similarly, the rings can be used in high temperature applications involving dissimilar materials such as steel shafts to plastic glass filled fan hubs or impellers. Read more below
HANDLES & KNOBS
Quickly assembling a handle or knob onto a shaft reduces production time and labor costs. Using epoxy or adhesives can be messy and doesn’t allow for future replacement. A tolerance ring rapidly attaches handles or knobs onto shafts and still allows for future repair or replacement.
Bushings and Sleeves
A tolerance ring’s unique wave properties provide a secure grip for holding bushings (i.e., bronze, plastic) and sleeves both firmly and gently in place. Torque and axial retention requirements are met while cushioning them from thermally induced stresses from adjacent components.Standard BN Ring Size Chart
Below is our detailed chart of BN type rings, designed for typical bearing sizes. We keep many of these in stock, however, we often do custom ring development for specific needs. For anything not shown below, please fill out the New Project Information Form below, and we’ll work with you to develop a ring that meets or exceeds your needs.
| BN RINGS | DIAMETRAL 1 CLEARANCE | TYPICAL BORE FOR TORQUE | Typical Bearing Bore For Bearing Mount |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| d nominal | d (in) | 7/2 (in) | Part Number | d min (in) | D max (in) | G1 (in) | G2 (in) | Radial Capacity/ (lbs) | Torque Capacity @ G13 (in-lbs) | TC (in-lbs) | D min (in) | D max (in) | Dmin (in) | D max (in) |
| 3/16 | 0.188 | 0.250 | BN018025C | 0.149 | 0.189 | 0.032 | 0.039 | 50 | 3 | 1.8 | 0.153 | 0.155 | 0.149 | 0.150 |
| 5 mm | 0.197 | 0.236 | BN5X6C | 0.159 | 0.198 | 0.032 | 0.039 | 50 | 3 | 2 | 0.162 | 0.164 | 0.159 | 0.160 |
| 6 mm | 0.236 | 0.236 | BN6X6C | 0.198 | 0.237 | 0.032 | 0.039 | 85 | 4 | 2 | 0.201 | 0.203 | 0.198 | 0.200 |
| 1/4 | 0.250 | 0.250 | BN025025C | 0.211 | 0.251 | 0.032 | 0.039 | 105 | 7 | 4 | 0.215 | 0.217 | 0.211 | 0.213 |
| 5/16 | 0.313 | 0.250 | BN031025C | 0.254 | 0.314 | 0.048 | 0.058 | 55 | 11 | 8 | 0.262 | 0.264 | 0.254 | 0.256 |
| 8 mm | 0.315 | 0.197 | BN8X5S | 0.257 | 0.316 | 0.048 | 0.058 | 125 | 9 | 5 | 0.264 | 0.266 | 0.257 | 0.259 |
| 3/8 | 0.375 | 0.250 | BN037025S | 0.317 | 0.376 | 0.048 | 0.058 | 190 | 21 | 12 | 0.323 | 0.326 | 0.317 | 0.320 |
| 10 mm | 0.394 | 0.276 | BN10X7S | 0.336 | 0.395 | 0.048 | 0.058 | 200 | 24 | 17 | 0.342 | 0.345 | 0.336 | 0.339 |
| 12 mm | 0.472 | 0.197 | BN12X5S | 0.414 | 0.473 | 0.048 | 0.058 | 200 | 31 | 18 | 0.420 | 0.423 | 0.414 | 0.417 |
| 1/2 | 0.500 | 0.250 | BN050025S | 0.442 | 0.501 | 0.048 | 0.058 | 240 | 37 | 21 | 0.448 | 0.451 | 0.442 | 0.445 |
| 9/16 | 0.563 | 0.250 | BN056025S | 0.505 | 0.564 | 0.048 | 0.058 | 240 | 47 | 28 | 0.511 | 0.514 | 0.505 | 0.508 |
| 15 mm | 0.591 | 0.236 | BN15X6S | 0.532 | 0.592 | 0.048 | 0.058 | 270 | 49 | 30 | 0.539 | 0.542 | 0.532 | 0.535 |
| 5/8 | 0.625 | 0.250 | BN062025S | 0.567 | 0.627 | 0.048 | 0.058 | 300 | 75 | 38 | 0.573 | 0.576 | 0.567 | 0.570 |
| 17 mm | 0.669 | 0.472 | BN17X12S | 0.611 | 0.671 | 0.048 | 0.058 | 640 | 185 | 92 | 0.617 | 0.620 | 0.611 | 0.614 |
| 11/16 | 0.688 | 0.375 | BN068037S | 0.629 | 0.690 | 0.048 | 0.058 | 510 | 160 | 80 | 0.636 | 0.639 | 0.629 | 0.632 |
| 3/4 | 0.750 | 0.500 | BN075050S | 0.672 | 0.752 | 0.066 | 0.078 | 880 | 200 | 120 | 0.681 | 0.684 | 0.672 | 0.675 |
| 20 mm | 0.787 | 0.472 | BN20X12S | 0.710 | 0.789 | 0.066 | 0.078 | 840 | 175 | 110 | 0.718 | 0.721 | 0.710 | 0.713 |
| 7/8 | 0.875 | 0.500 | BN087050S | 0.797 | 0.877 | 0.066 | 0.078 | 1000 | 300 | 185 | 0.806 | 0.809 | 0.797 | 0.800 |
| 15/16 | 0.938 | 0.500 | BN093050S | 0.859 | 0.940 | 0.066 | 0.078 | 1125 | 405 | 245 | 0.869 | 0.869 | 0.859 | 0.862 |
| 25 mm | 0.984 | 0.472 | BN25X12S | 0.907 | 0.986 | 0.066 | 0.078 | 1100 | 275 | 170 | 0.915 | 0.918 | 0.907 | 0.910 |
| 1 | 1.000 | 0.500 | BN100050S | 0.922 | 1.002 | 0.066 | 0.078 | 1200 | 400 | 245 | 0.931 | 0.934 | 0.922 | 0.925 |
| 1 1/8 | 1.125 | 0.500 | BN112050S | 1.047 | 1.127 | 0.066 | 0.078 | 1300 | 515 | 315 | 1.056 | 1.059 | 1.047 | 1.050 |
| 30 mm | 1.181 | 0.512 | BN30X13S | 1.104 | 1.183 | 0.066 | 0.078 | 1400 | 550 | 340 | 1.112 | 1.115 | 1.104 | 1.107 |
| 1 3/16 | 1.188 | 0.875 | BN118087S | 1.109 | 1.190 | 0.066 | 0.078 | 2500 | 1150 | 700 | 1.119 | 1.122 | 1.109 | 1.112 |
| 1 1/4 | 1.250 | 0.750 | BN125075S | 1.172 | 1.252 | 0.066 | 0.078 | 1200 | 740 | 450 | 1.181 | 1.184 | 1.172 | 1.175 |
| 1 3/8 | 1.375 | 0.688 | BN137068S | 1.297 | 1.377 | 0.066 | 0.078 | 1170 | 770 | 410 | 1.305 | 1.309 | 1.297 | 1.301 |
| 35 mm | 1.378 | 0.669 | BN35X17S | 1.300 | 1.380 | 0.066 | 0.078 | 1220 | 785 | 415 | 1.308 | 1.312 | 1.300 | 1.304 |
| 1 1/2 | 1.500 | 0.750 | BN150075S | 1.422 | 1.502 | 0.066 | 0.078 | 1500 | 1120 | 595 | 1.430 | 1.434 | 1.422 | 1.426 |
| 40mm | 1.575 | 0.551 | BN40X14S | 1.497 | 1.577 | 0.066 | 0.078 | 1200 | 850 | 450 | 1.505 | 1.509 | 1.497 | 1.501 |
| 1 5/8 | 1.625 | 1.000 | BN162100S | 1.547 | 1.627 | 0.066 | 0.078 | 2200 | 1800 | 955 | 1.555 | 1.559 | 1.547 | 1.551 |
| 1 3/4 | 1.750 | 1.000 | BN175100S | 1.672 | 1.752 | 0.066 | 0.078 | 2400 | 2100 | 1115 | 1.680 | 1.684 | 1.672 | 1.676 |
| 2 | 2.000 | 1.000 | BN200100S | 1.922 | 2.002 | 0.066 | 0.078 | 2700 | 2900 | 1775 | 1.931 | 1.934 | 1.922 | 1.926 |
Tolerance Rings can be used to transmit torque from one cylindrical component to another, without the need for costly splines or expensive keyways. Gears, pulleys, disks, sprockets, flywheels, rollers, impellers are a sample of the many torque transmitting components that can be mounted with tolerance rings. Unlike a keyway’s tolerances which result in backlash with a change in rotational direction, the tolerance ring provides zero backlash.
Depending on the diameter of the mounting components and the configuration of the tolerance ring, torques from .015 ft.-lbs. to 175 ft.-lbs. and much higher can be handled prior to slippage. The amount of torque transmitted will vary with tolerance ring configurations, diameters, material hardness, surface finish, and the amount of thermal expansion/contraction occurring between components. The slippage can provide natural torque overload protection, acting as a “fuse” and preventing damage to less sturdy components such as plastic gear teeth.
New Project Information Form
Please fill out as much information about your project below as possible. We may respond with further questions about your project’s specs, so please let us know who we should reply to.
