Fabreeka® Bushings & Washers Fabreeka® manufactures a wide variety of bushing and washer sizes to complement the Fabreeka® pads at bolted connections for the reduction of shock, vibration and structure-borne noise. Fabreeka® bushings and washers are available for all bolt sizes. This arrangement eliminates "shorting" of vibration or structure-borne noise by interrupting the metal-to-metal contact between the machine base and the hold-down bolt. A minimum wall thickness of 3/32" is recommended for bushings. Fabreeka® bushings are manufactured by wrapping a single ply of fabric in a "round and round" fashion over an arbor to give the inside diameter. The bushing is then placed in a mold and cured under heat and pressure in a vulcanizing press to give the outside diameter.

General Fabreeka® bushing information: Minimum wall thickness of 3/32" is recommended Fabreeka® bushing ID is the same as the bolt OD, and the bushing OD is the same as the hole it will fit into. To facilitate inserting Fabreeka® bushings, they can be lubricated with a soap solution. In general, tolerances on rubber impregnated bushings need not be controlled to the same closeness as required for metal fits, since Fabreeka® is a compressible/flexible material. In general production, the tolerance on bushing dimensions is ±1/32". If closer tolerance is required, please contact Fabreeka's® Engineering Department.

Fabreeka® washers are used under the steel washers of the hold-down bolts of Fabreeka® mountings to absorb the rebound shocks and afford complete isolation by eliminating the transmission of vibration through the bolts and steel washers. It also aids in preventing the bolts from becoming loose.

General Fabreeka® washer information: Always use a heavy steel washer, slightly larger than the Fabreeka® washer where possible, directly under the nut or bolt head to assure uniform stress distribution on the Fabreeka® washers. Following is a partial Torque Chart for standard washer/bolt sizes. Please contact Fabreeka's® Engineering Department for a complete guide.

Fabreeka® Washer Dimensions and Bolt Torque Guide*

*Notes:

1. The above recommended torque takes into consideration the creep/set of Fabreeka® material with time therefore DO NOT RETORQUE. In general, creep/set will reduce the torque to about one-half the above values. This usually occurs within 7 days of the original torquing.
2. The guide to proper torque is an aid to developing proper bolt force without overstressing the Fabreeka® washers. Steel-to-steel torque values must never be used with Fabreeka® washers because they would severely overstress the Fabreeka® material.
3. This guide supplements the "visual observance" method where the nut is tightened until the Fabreeka® washer begins to bulge.
4. The above is only a "Guide", consequently there will be instances where less and possibly greater torque is required. For example, when a relatively small Fabreeka® pad is used in conjunction with the above Fabreeka® washers and isolation requirements are critical, we would then recommend using one-half the above values and possibly less depending on the relative Fabreeka® pad to Fabreeka® washer size.
5. The torque values are based on the well known empirical formula: T = 0.2 x D x L
   
   T = Torque (in. - lbs.)
   D = Bolt Diameter (inches)
   L = Bolt Force (lbs.)



6. The Fabreeka® washer sizes listed are based on standard (U.S. Wrought) steel washer dimensions. Double steel washers can be used, if necessary, to avoid "dishing" which might load the Fabreeka® washer at the I.D. to the point of failure. For machines having oversized anchor bolt holes to facilitate locating, use single or double steel washers on both sides of the Fabreeka® washer.

Typical Applications include diverse uses on equipment such as:

• Elevators
• Compressors
• Light Poles
• Fork Lift Trucks
• Transformers
• Electric Motors
• Pumps
• Machine Tools
• Presses
• Packaging Machinery
• Railroad Cars
• Transit Cars
• Heavy Duty Off-Road Machinery

Please contact Fabreeka® to request a brochure.
Please visit our application section to learn more about Fabreeka's® diverse applications.