Using an IRRI axial flow thresher

Positioning of the thresher

• Position the thresher on a level area close to the crop stack to minimize handling and shattering losses.
• Spread cloth, canvas, or mat underneath the thresher to collect spilled grain from the grain discharge chute or due to shattering during handling.
• Install the cylinder, cover, and feed tray if dismantled during field transport.
• Position the thresher so that the straw is thrown with the direction of the wind.  This will eliminate the blowing of straw, chaff, and dust back toward the operator and the threshed grain.

Check the machine

• Check each belt's alignment and tension.  Adjust the idler pulley on the blower/cylinder belt to correct tension. Improper alignment and tension are the major causes of premature belt failure.

• Check pulley surfaces.  Rough grooves must be smoothened with a fine file if nicked.  Cracked pulleys should be replaced immediately.

• Open the cover and check all pegs on the threshing cylinder for tightness.  Loose pegs will damage the machine and can be dangerous to the operators.

• Examine the pegteeth for wear.  Maximum wear occurs at the feed end of the cylinder and is more prominent at the leading side in the direction of rotation.  Worn pegs must be rotated 180 degrees or interchanged with those located near the straw paddles.  Badly worn pegs must be replaced or rebuilt by welding.
• Rotate the threshing cylinder manually at least five revolutions to ensure that there are no obstructions or interferences.
• Make sure there are no loose or missing bolts and set screws.  Tighten or replace as necessary.

• Lubricate all bearings with good quality grease  (see maintenance and service section)  The belt idler and oscillating screen eccentric bearings are lubricated for life, thus require no lubrication.
• Check engine oil and fuel levels.  Follow the engine manufacturer's recommendations.
• Start the engine and allow it  to warm up.  Feed the thresher with the crop to be threshed for performance checking. Increase cylinder speed if excessive amounts of unthreshed and unseparated grain are observed with the straw. Optimum threshing and cleaning is obtained with cylinder speeds of 600 to 700 rpm.

• Start the engine.

• Load the feed tray with harvested crop with the panicle away from the operator, so it is fed panicle first into the thresher.
• Feed the crop at a uniform rate. Adjust the feed rate to match the condition of the material. Maintain maximum feeding rate without overloading the engine.

• Adjust the cleaner to suit the threshing conditions.
• Adjust blower openings to ensure sufficient air flow needed for winnowing.  Open slowly to provide more air for the cleaner until a small amount of mature grain flows over the wind-board. For threshing dry paddy less air is needed while for wet paddy a higher airflow is required.

• Adjust the angle of the wind-board. For dry paddy, the wind-board should be set at its maximum inclination.  For threshing wet paddy, the inclination of the wind-board must be reduced. To obtain extra-clean paddy, set the wind-board at a low inclination and increase the air shutter opening.  This process will blow more grain over the wind-board, but this can be recovered by recycling the separated impurities through the thresher.
• Always use a stick to remove clinging straw from the oscillating screen to protect hands from possible injury.