Extend Chain Life

Deal with Elongation: Chain elongation (“stretch”) is the increase in measured chain length due to wear between the pin and bushing. In general terms, 2% is considered the wear-elongation limit at which chain replacement is suggested. Use a chain-wear scale to easily measure this elongation.

Deal with Elongation: Chain elongation (“stretch”) is the increase in measured chain length due to wear between the pin and bushing. In general terms, 2% is considered the wear-elongation limit at which chain replacement is suggested. Use a chain-wear scale to easily measure this elongation.

Don’t overlook chains and components during your maintenance rounds.

The chain systems in your operations keep your production processes and profitability moving in the right direction. Although they may often be out of sight, don’t let the components in these critical systems slip your mind when it comes to equipment maintenance. The power-transmission experts at U.S. Tsubaki® offer these reminders for production facilities that want to achieve the longest service life and greatest returns possible from their chains and the processes they support.

Alignment:

• Use a level to verify that shafts are parallel.
• Confirm sprocket axial alignment with a straightedge or laser tool. Axial alignment is correct when there are no gaps between sprockets and the straightedge.

Lubrication:

Maintain a film of lubricant between pin and bushing to minimize chain-wear elongation and increase service life (see sidebar).

• Manual lubrication: Oil is applied with an oil filler or brush on the slack side of the chain. Apply at fixed intervals (usually about every 8 hr.) or as often as necessary to prevent the bearing areas from becoming dry.
• Drip lubrication: A simple case can be used. Oil from the oil cup is supplied by drip-feeding. Apply 5 to 20 drops of oil/min. for every strand of chain. Actual quantity depends on chain speed.
• Oil-bath lubrication: The chain is installed in a leak-free casing. Chain should be submerged in oil 1/4- to 1/2-in. deep. If too deep, the oil may overheat and lose effectiveness.

Tensioning:

• Adequate slack should be maintained for effective roller-chain operation. Excessively tensioned chain may reduce chain life.
• The chain slack that you can move by hand should be about 4% of the span. Reduce the slack to 2% if one of the following conditions apply:
  • centerline of sprockets is vertical or almost vertical
  • center distance of sprockets is more than 3 ft.
  • chain is subjected to heavy loads and frequent starts
  • chain is subjected to suddenly reversing loads.
• If the chain slack side is on top, eliminate the excess amount.
• When the center distance is short, chain slack should be adjusted by increasing the center distance.
• When the center distance is long, the chain slack should be adjusted by installing
  an idler.
• If vibration occurs, due to high chain speed, install a guide.
• If the centerline is vertical, install an idler, which functions to eliminate extra slack.  If the driving shaft is on the lower side, an idler must be installed. MT

To learn more about chains and other power transmission products, visit ustsubaki.com. To obtain a full-color poster on chain maintenance with a detailed troubleshooting guide and a U.S. Tsubaki Chain Wear Scale for measuring elongation, email information@ustsubaki.com.