When selecting a heavy hex head bolt, it is essential to consider factors such as the specific application requirements, load capacity, and material compatibility

4) Allowable total eccentricity
Standard Sealing Case Designs
1) Oil seals for cars

Obtaining adequate adhesion of fluoroelastomer compounds to metal inserts is a major consideration in fabrication of shaft seals. Adhesive systems worked out for bisphenol-cured VDF/HFP/TFE elastomers often do not perform adequately for peroxide-curable fluoroelastomers and more base-resistant polymers that contain little or no VDF. The trend toward use of more resistant fluoroelastomers in shaft seals has necessitated considerable effort on compounding and adhesive system development to get adequate bonding of the new materials. Silane-type primers are often used to coat metal inserts; these contain residual active groups such as amine functions that interact with the fluoroelastomer compound to attain good adhesion, especially for VDF/HFP/TFE elastomers. Other adhesive systems, using epoxy compounds or tie-coats, may be necessary for difficult bonding situations.3
Sealing principle: Since there is an oil film controlled by the oil seal edge between the oil seal and the shaft, the oil film has fluid lubrication characteristics.