Updated: Jan 20, 2022
Whether you’re a recent tub grinder convert or, like most others, you just didn’t read the horizontal grinder operator’s manual cover to cover … here’s a way to better harness all those horses and step up your production numbers.
First and foremost, it’s essential your Morbark grinder has an accurate, working inclinometer for the yoke bump settings to function effectively. Readings reflect angle and percentages of yoke adjustment, from 0% (down) to 100% (up). If your machine’s inclinometer is not correctly calibrated, you will struggle to find the yoke bump setting and auto-feed sweet spot for your material. Note: If you are experiencing “jogging”—repeated back and forth motion—of the infeed belt, it’s time to check the inclinometer.
Dialing in on the auto-feed sweet spot: Any time the grinder is moved to a new location and/or a change of feed material is introduced, it is a good time to reset the yoke bump. This is best achieved by feeding material into the grinder and observing the yoke’s range of movement. The setting should then be set to the mid-point of the observed range of movement. With a more uniform, consistent product such as mulch, that setting will be in the 30-40% range. With more size-inconsistent material—such as that encountered on a land clearing site—the mid-point may occur in the 50-60% range.
The yoke is designed to apply downward pressure on material and ease it into the mill chamber so if this setting is too low, pressure will be applied too soon and the feed chain will be over-pressured, resulting in backing up of the feed chain, the mill running empty and product consistency being negatively impacted. Remember, this setting is also dependent on the volume of material entering the chamber (thus the importance of the initial observation and set up) … so the more material, the higher the setting. As a result, it is also important to maintain as consistent a feed rate as possible after the setting is entered.
When all these factors—initial reaction of yoke to material fed into machine, yoke bump setting, flow of material into the mill chamber—are dialed in, the result is not only peak flow and production as the yoke rides the material with balanced pressure, but also optimal consistency of product … the Holy Grail of any grinding operation.
So, bottom line to optimizing your grinder’s production is:
Understanding how the yoke adjustment works
Varying your yoke bump set-up for different material types
Accurately dialing it in for each of those material types
And be patient, it usually takes some trial and error for operators to dial in on their material’s sweet spot. That said, once you do, your production numbers will peak, letting you know you’re there. If you have any questions, feel free to contact me, Aaron, at (513) 678-2430 or leave them in the comments section below.
Columbus Equipment Company’s Aaron Dunham is a Product Support Sales Representative and equipment specialist with oodles of experience in the land clearing and recycling industries.