Bucking bars are used to create the back end of solid rivets which are also known as shop heads. They are held at the opposite side of the rivet. A pneumatic rivet hammer is then used to hammer blows at factory dome-heads.
Bucking bars are used to create the back end of solid rivets which are also known as shop heads. They are held at the opposite side of the rivet. A pneumatic rivet hammer is then used to hammer blows at factory dome-heads. The aircraft industry uses dozens of bars of different shapes and sizes. One shape that is used for all-round general riveting is the heel-toe shape bar.
The heel-toe shape bar is versatile in its applications. It eases access to areas that are tight and difficult to reach. It has just the right weight that makes it ideal for large and small rivets. Its shape and size makes it easy to handle and control. The bar has a weight of 1.9 pounds. It is manufactured from precision cast iron and its surfaces are polished to provide a smooth and trouble free working area. All its sharp edges are de-burred to make it safe for work materials and for handling. The smooth working surfaces can be re-polished using an agent that does not alter the material's hardness.
Bucking bars made from different materials but of the same shape were put to the test. Muscle grip and vibration activity were observed while riveting tasks were performed. One bar was composed of 90% tungsten, while the other was made of more than 90% tungsten. Two other bars, one cold rolled and the other stainless steel were also observed.
Less vibration was observed on the two tungsten bars compared to the stainless steel and cold rolled bars. No muscle activity was observed on the hands extensor and flexor muscles. The results suggested that using bars made of heavier materials reduced the vibration transmitted to the hand.
Riveting tasks in aircraft assembly may range from the use of power drills, rivet guns, and bucking bars. In attempts to minimize injuries, vibration dampened rivet guns have been designed. The downside to these new designs is that operators report low feel when riveting. This has led to overdriving of rivets because it is hard to determine when the rivet is set. Ultimately, these tools lead to low quality rivets. Such rivets usually have to be redone.
Reduction of vibration exposure has been identified as the best way to minimize injury. Other avenues of preventing vibration related conditions are minimizing the duration of exposure to vibration and reducing the vibration acceleration. Using alternate material in the manufacture of bucking bars like tungsten instead of steel has seen marked improvements. Tungsten bars have significantly minimized vibration.
Dangers of vibration include stiffness in the wrist, pain in the joint and white finger disease. Other complications are carpel tunnel syndrome and musculoskeletal disorders. Tungsten bucking bars produce significantly less vibration compared to cold rolled and stainless steel bars.
The effect of having a hard or loose grip on the rivet guns still remains unknown. When the vibration is high, the tools tend to be held more tightly. Less vibration means the riveting gun is not gripped tightly. Tungsten has been observed to be an effective material in designing bars that vibrate less. Tungsten is effective in reducing the chances of injury.
By Stanford Materials http://stanfordmaterials.com/
Stanford Materials Corporation is a worldwide supplier of various oxides, metals, alloys, advanced ceramic materials, and minerals. It was established in 1994 to supply high quality rare earth products to our customers in the research and development fields. To meet increasing demands for rare earth products and other materials, Stanford Materials now carries a variety of materials to serve not only our customers in research and development but also manufacturers in the ceramic, metallurgy and electronic industries. Stanford Materials carries both technical grade materials for industries as well as high purity chemicals (up to 99.99999%) for research institutes.