In the Shop
As a farm machinery mechanic and writer, Dan brings a hands-on approach that only a pro can muster. Along with his In the Shop blog, Dan writes a column by the same name as well as the Shop Series for Farm Journal magazine. Always providing practical information, he is a master at tackling technical topics and making them easy for all of our readers to understand. He and his wife, Becky, live near Bouton, Iowa.
Perfect Platform Performance
Aug 31, 2009
Everybody wants their small grain platforms to cut well enough to leave soybean and other small grain fields as smooth as a pool table's top. Money, painstaking adjustments and a roll of electrician's tape can improve the performance of most platforms.
Money is the first component necessary to improve platform performance because it's expensive to keep knife sections, guards and other components in top condition. Everybody accepts that knife sections must be razor sharp, but even a sharp knife section won't cut well if it's shuttling back and forth through rock guards with dulled, rounded edges. Replacing knife sections and guards when they show only minor wear gets expensive because you're literally throwing away components that aren't entirely worn out; they're just slightly dull. But that's the cost of optimum platform performance.
Painstaking adjustments allow small grain platforms to cut crop with minimal effort and feed that crop into the combine without hesitation or bunching. Cutterbars should be adjusted so the guards and knives run slightly "nose down." As crop pushes into a cutterbar assembly that is slightly nose down the crop applies pressure that pushes the knife against the cutting surface of the guards, improving the shearing action. If the cutterbar assembly is tilted slightly "nose up," the crop lifts the knife slightly away from the cutting edges of the guards, reducing cutting efficiency.
Reel height and speed are extremely dependent on crop conditions but critical to optimum cutting performance. Some operators disagree, but I like to see reels low and as close to the cross auger as possible. I want the reel teeth lightly (lightly!) pressing the cut but still upright crop lightly into the flighting on the cross auger. The reel should be turning 10 percent faster than the drive wheels on the combine. If everything is adjusted properly, crop should move from the cutterbar then back against the cross auger then sideways to the throat of the combine feederhouse in one continuous motion. If there is any hesitation or bunching, something is out of adjustment.
Automatic header height control systems vary from combine manufacturer to combine manufacturer, but the concept is universal: determine an average height for the automatic system to maintain. Whether the settings are made in the cab or on the control box on the end of the platform, lower the platform so it is simply firm against the ground and note that height. Then raise the platform until the cutterbar just starts to come off the ground. Adjust the cutterbar to run halfway between those two points. Beware of setting the "lowest" point with the platform pressed so hard against the ground that the combine's tires are almost in the air-- the resulting mid-point will be much lower than desired and the platform will tend to push dirt and collect rocks.
It can take hours--even days--to meticulously go through a large platform and replace any less-than-razor sharp components and then make adjustments to cutterbar tilt, reel height, auger position and header height control systems. It takes a lot of self-control to replace parts that are only slightly worn, and a lot of patience to painstakingly check all the possible adjustments on a 30-, 35- or even 40-foot platform. But those are the keys to getting platforms to leave small grain fields as smooth as the top of a pool table.
Oh--I almost forgot the final element in perfecting platform performance: a roll of electrician's tape. Take a small piece of tape and place it over the ground speed display on the cornerpost in the combine cab. Ignore how fast your combine says it's going.
IGNORE HOW FAST YOUR NEIGHBOR'S COMBINE APPEARS TO BE GOING. IGNORE HOW FAST YOUR NEIGHBOR SAYS HIS COMBINE IS GOING.
Adjust your ground speed according to the way YOUR platform is leaving stubble in YOUR field under YOUR conditions. Stubble should be standing straight, sharply sheared, not pushed over or leaning with a ragged cut. If you cannot stand to run a combine without knowing actual ground speed, it is safe to say that most platforms do a nice job at 4.5 mph. Well-maintained and adjusted platforms under good conditions will hum along at 5.5 mph and have been known to work well at 6 mph.
Those guys who say they cut soybeans or small grains at 7 mph and do a "perfect" job...? They're better at adjusting, maintaining and operating small grain platforms than I am.