FAQ – Frequently Asked Questions


To maintain the good quality of a bar clamp in the long-term, proper care is essential. 

The function of a screw clamp is based on the friction and tilting between rail and sliding arm. It is important, therefore, that the rail is always kept free of grease, oil or dried glue. Particularly critical on the rail are waxes and release agents containing silicone. Such residues must be removed as quickly as possible using solvents, wire brushes or sandpaper. Both the spindle and the pressure plate joint should be lubricated regularly with a little oil. Spray oil is especially suitable for this purpose. In this way, the smooth running of the screw clamp is maintained for a long time with optimum clamping force.

If there is a grub screw on a malleable cast iron screw clamp, which prevents the sliding arm from slipping through, it can be readjusted by a quarter turn when the support starts to diminish. With all-steel screw clamps, attention should be paid to any shine forming on the rail, as this can lead to slipping of the sliding yoke. If shiny spots are visible, they can be roughened on both sides with emery cloth in grain size 100 to ensure safe working again.



There are several ways to identify a clamp. The most accurate way is by the product part number. Part numbers can be found on the rail, operating jaw, and the handle, depending on the style of clamp. If the part number is worn off due to use, the end user can take pictures of the whole clamp, take specific measurements of the opening capacity and throat depth (from the center of the spindle to the nearest edge of the rail) and provide these to BESSEY Tools to help identify the clamp.