Hydraulics and Hydraulic Tools


If you have worked in a maintenance department, you will know how tiring the work is of bolt tightening. Here is how you do it by hydraulic bolt tensioners.


Manual Bolt Tensioning Limitations

A man can supply about 20 pounds of force while tightening a bolt and a woman generally less force at about 15 to 18 pounds. This force coupled with a long handle of about 3 to 4 feet, you can apply a force of not more than 100 ft-lb. with a jerk, the force applied can increase by about 3 to 4 times and a force of about 250 to 400 ft-lb can be applied.


The force applied with a jerk cannot be controlled and in such case, there is a possibility that the smaller bolts might just break.

Work Made Easy with Hydraulic Bolt Tensioners

If you continue the work of bolt tightening day in and day out, you will soon be tired and ready to quit your job next week. On some jobs you will not even be able to do it by hand. It is at such times that you require hydraulic bolt pensioners.

Benefits of using Hydraulic Bolt Tensioners

There are some major benefits of using hydraulic bolt tensioners. These include,

1.      You can do simultaneous tightening of many numbers of bolts at a time. This is of importance when you wish to tighten bolts on opposite sides of a flange. With normal bolt tightening only one team can work on a flange due to space limitations

2.      The bolt tightening force is equal on all the bolts. This means that a bolted joint is uniform in strength over the entire periphery of flange.

3.      You can load the bolt accurately and the force on each bolt is known. This makes the work of designer more accurate and he/she can load the material to its plastic limit. Thus there is saving in material costs.

4.      The manual power required for bolt tightening is reduced. The work can be automated easily and less human element is used in work.

5.      The hydraulic bolt tensioners reduce the number of bolts required for a flange joint as the bolts can be designed close to their plastic deformation point and thus carry more load per bolt.

6.      The possibility of accidents due to slippage of hand or the problem with spanners get reduced., thus making it more safe to use than the spanner and lever work of bolt tightening.

7.      Some times, the bolts have to be heated to get the pre-stress on the bolt. Hydraulic tensioners reduce chances of accident due to burning of skin.

8.      Where the non sparking bolt tightening is to be used (as in a fuel depot) hydraulic bolt tightening decreases the possibility of accidents due to fire.

9.      The workers doing the bolt tightening do not get fatigue. The productivity of worker increases due to hydraulic bolt tensioners.

10. Bolt tensioning load can be accurately measures as there is no shock to the bolt assembly. The bolt tightening with hammer introduces a fair amount of shock loads on the bolt assembly and the measurement device does not retain the position and require adjustments after every rotation of nut.