{"id":8491,"date":"2025-04-08T07:05:46","date_gmt":"2025-04-08T12:05:46","guid":{"rendered":"https:\/\/wearpartsllc.com\/?p=8491"},"modified":"2025-09-22T10:35:42","modified_gmt":"2025-09-22T15:35:42","slug":"how-to-check-seed-disc-openers","status":"publish","type":"post","link":"https:\/\/wearpartsllc.com\/how-to-check-seed-disc-openers\/","title":{"rendered":"How to Check Your Seed Disc Openers"},"content":{"rendered":"\n

When you buy a new part for an engine, you don\u2019t expect to have to check that it works \u2013 right? It\u2019s assumed that new parts will always function as they should \u2013 so why doesn\u2019t this hold true for seed opener assemblies?<\/p>\n\n\n\n

Time and again, we hear from farmers who say they\u2019re sick of wasting time pre-qualifying seed opener blades before they can take their planter into the field \u2013 that\u2019s hours and hours, laid on your back, messing around with business cards to get your openers shimmed up and ready to plant.<\/p>\n\n\n\n

That\u2019s why we developed the Wearparts Guaranteed True\u2122\ufe0f promise \u2013 a field-ready guarantee that takes all the hassle out of prepping your planter and gives you back hours of valuable time to get the real work done.<\/p>\n\n\n\n

We test 100% of our seed opener assemblies<\/a> \u2013 no exceptions \u2013 to ensure they meet industry-leading tolerances on axial and radial runout. That means no wobble or lope \u2013 and no more time wasted on pre-qualifying openers, sending back faulty ones, and waiting for replacements. Let\u2019s dig deeper into how and why we do it.<\/p>\n\n\n\n

\"Aerial<\/figure>\n\n\n\n

Why does seed opener precision matter?<\/h2>\n\n\n\n

Seed opener assemblies are comprised of two disc blades, mounted in pairs on a planter\u2019s frame, and angled towards each other so the edges of the two blades meet at their lowest point (called the pinch point). As the blades rotate, this causes them to cut a v-shaped trench in the soil, into which a seed is dropped via the seed tube on a planter. <\/p>\n\n\n\n

Gauge wheels dictate how deep the trench is cut \u2013 and this depth is precisely calibrated according to the type of seed being planted, and its preferred germination depth. In order to achieve optimal conditions, the seed needs to drop into the bottom of the trench. For this to happen, the trench needs to be precise and clean \u2013 if the blades don\u2019t meet precisely, a number of problems can occur:<\/p>\n\n\n\n

    \n
  • Their cutting action is impaired, so surface debris can get pushed down into the trench, known as hairpinning<\/li>\n\n\n\n
  • The trench can end up with a W-shaped profile instead of a V, impacting seed depth and increasing the risk of air pockets<\/li>\n\n\n\n
  • The sidewalls of the trench can be unstable and collapse, leaving some seeds too close to the surface<\/li>\n<\/ul>\n\n\n\n
    \"Mechanic<\/figure>\n\n\n\n

    How do farmers check the pinch point of a seed opener?<\/strong><\/h2>\n\n\n\n

    Prior to planting, farmers typically have to check the pinch points of each pair of seed opener blades in a process called shimming.\u00a0<\/p>\n\n\n\n

    The most common way is to insert a cardboard gauge (normally two old business cards, which are the ideal size for the job) into the seed opener assembly and sliding them down to the point where the blades come together, and they can\u2019t slide any more. <\/p>\n\n\n\n

    The distance between the two cards at this point is the \u2018pinch point\u2019 \u2013 and this should measure between 1.5 and 2 inches in order to open a trench effectively. On new blades, the pinch point can be adjusted by adding or removing spacers to adjust the angle of the blades.<\/p>\n\n\n\n

    When to replace seed disc openers? <\/h2>\n\n\n\n

    As a seed opener wears, the pinch point will get smaller \u2013 and by the time a disc shows half an inch of wear, it will no longer be able to cut a consistent trench \u2013 so it\u2019s time to replace. <\/p>\n\n\n\n

    But even on new blades, manufacturing issues can cause problems with pinch point accuracy \u2013 specifically radial runout (lope) and axial runout (wobble). These issues can vary in severity, but in all cases, they will lead to inferior trenches and potentially impacted crop yields. Let\u2019s explore this in more detail.<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    What is axial runout (wobble) in a seed opener?<\/h2>\n\n\n\n

    Axial runout refers to how much the blade wobbles from side to side as it spins. Imagine a record on a turntable that isn\u2019t perfectly level\u2014it moves up and down slightly as it turns.<\/p>\n\n\n\n

    Axial runout can be created during manufacturing if the blade itself isn’t perfectly flat or if it isn\u2019t mounted perfectly parallel on the hub. It can be caused by uneven pressing of the seed opener assembly during production, or if the hub housing isn\u2019t completely flat \u2013 precision manufacturing of all component parts is a must.<\/p>\n\n\n\n

    Too much axial runout can lead to uneven seed trench walls, inconsistent seed placement, and increased wear on the bearings and other components.
    <\/p>\n\n\n\n

    What is radial runout (lope) in a seed opener?<\/strong><\/h2>\n\n\n\n

    Where axial runout is a side-to-side movement, radial runout is a forward and back motion. It\u2019s caused when the seed opener blade isn\u2019t perfectly centered, so instead of spinning in a perfect circle, it \u2018lopes\u2019 forward and back, which will cause the blade to cut deeper for part of its circumference, and shallower for the other part.<\/p>\n\n\n\n

    Radial runout can occur if the blade\u2019s central hole isn\u2019t perfectly aligned during manufacturing, if the blade is slightly warped, or if the hub or bearing have inconsistencies. As well as uneven cutting depth, it can also cause vibration, leading to premature wear on both the blade and the opener assembly.<\/p>\n\n\n\n

    Why do Wearparts test 100% of seed openers?<\/strong>
    <\/h2>\n\n\n\n

    Even with the best quality control processes in place during the manufacture of seed opener blades and hub assemblies, tiny variations can occur. These discrepancies may not fall outside of the acceptable tolerances for the individual components \u2013 but when the components are assembled, they can add up to more or less runout for that specific seed opener. <\/p>\n\n\n\n

    Testing a representative sample of our seed openers can\u2019t tell us whether every seed opener we make is within the acceptable runout tolerance, because the same blade mounted on two different hubs can have different runout performance, and vice versa.  This is why we test 100% of our seed openers before they leave our warehouse.<\/p>\n\n\n\n