Developing a guide for farmers or local machine shops to build an affordable roller-crimper by repurposing tillage equipment

This project entails two research projects 1) build an affordable roller-crimper from a recycled disc and salvaged tillage equipment parts (Figure 1) and 2) study the effectiveness of our constructed crimper to terminate various cover crops.

Objective 1: Build an affordable roller-crimper

Gather materials

• Disc: There are several types of tillage equipment that can be recycled into a roller-crimper, but we found small to mid-size discs to be both affordable and easy to source in the Upper Midwest. For this project, an International 490 disc (22 ft. wing span) was selected as the roller-crimper frame. The size of crimper can easily be scaled up or down by simply selecting a larger or smaller piece of used equipment to serve as the frame. Fortunately, there are many used equipment in the Upper Midwest available in a variety of sizes that can be recycled into a roller-crimper.
• Crimper drums: To prevent gaps in cover crop crimping, the crimping drums need to overlap slightly. International 490 22' discs have two 6' wings with a 10' center section. Therefore, we salvaged two 6'8" steel tubes for the wings and an 11' steel tube for the center to serve as the crimper drums. All tubes were 16" outside diameter. We sourced the steel tubes from a local metal recycling center, which charged scrap price for the metal. This saved a lot of money compared to buying new steel tubes.
• Crimper blades and gussets: Steel plates (4" width, 1/4" thickness) were used for crimper blades. Blades affixed to wing drums (n = 88 blades) were cut to 20.75" in length, and blades affixed to center drum (n = 66 blades) were cut to 22.833" in length. Gussets (n = 462) (1 1/2" x 3", 1/4" thickness) were affixed to the back of crimper blades for support (3 gussets per blade).
• Crimper drum caps: Steel plates (n = 7 drum caps, 1/2" thickness) were cut to the inside diameter of crimper drums with 1 3/4" hole cut into the center to receive bearing assembly for attachment of drum to disc frame.
• Crimper drum axles: Steel bars (1 3/4" diameter) served as the axles for the crimper drums. Axles ran the entire length of each drum to provide strength and stability to the axle mechanism. This required 12' and 8'4" (n=2) lengths of steel bars for the center and wing drums, respectively.
• Wing drum toolbars: Steel toolbars (7" x 7" square steel tubing, 8' length) (n=2) were used to hang crimper drums from the wing frames. These were sourced from an scraped piece of farm equipment (International 800 Cyclo Air Planter).
• Crimper drum mounting brackets: Brackets were manufactured from 1/2" thick steel. Brackets attached to crimpers drum axles with bearings to suspend the crimper drums under the disc frame.

Assembly steps

All stages of assembly were recorded, and are available to the public in a how-to video series on Ecdysis Foundation's YouTube page.

1. Remove disc gangs from frame. Save gang assembly for parts or to be sold as scrap to offset some cost of build.
2. Make any needed repairs to disc frame, remember to check tires and hydraulic lines.
3. Prepare crimper drums for welding blades. 
   • Remove rust, paint, or any other foreign material from the drum surface, so it is only clean metal, ready to be welded.
   • Mark rows for attachment of crimper blades. First, a chalk line is snapped onto drum surfaces running the length of the drum. Chalk lines (n = 22 rows/drum) are spaced 2.2848" apart to ensure crimper rows are all equidistant apart on 16" outside diameter drums.
   • Mark attachment points of crimper blades along chalk lines. Crimper blades are arranged in a staggered fashion with 1" overlap between rows (Figure 2).
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4. Weld gussets to crimper blades. Three gussets were welded to back of crimper blade; one in the center and the other two gussets 1" from the blade edge.
5. Weld blades in premarked slots on crimper drums.
6. Weld endcaps onto crimper drums.  
   • Weld one of the endcaps to the center of the 12' axle of the center drum. This will support the middle of the axle. Cut three notches from the outside perimeter of this endcap before welding to the middle of the axle. The notches will allow water to flow from one side of the drum to the other when filling or draining. 
   • Test fit all endcaps in their respective drum ends before welding into place. Grind inside lip of crimper drums at 45° angle to help with fit and provide more surface area for weld. Then mount endcaps into the end of the drums with the axle running through the drum and endcap. The axle provides a convenient handle to center the endcap within the drum. Tack weld endcap in place and double check endcap is still centered. If centered, proceed to welding endcap in place.
7. Weld axles to endcaps where axle contacts crimper drum endcaps. Be sure axle is centered relative to the length of the drum before welding into place. (See photo for finished crimper drum.)
8. Assemble brackets that will hang drums form the disc frame by welding the pieces together.
9. Attach crimper drums to disc frame.
   • Start with the center drum. Center the drum under the front of the disc frame in a position that prevents it from hitting the road tires. Next, slip brackets with bearing attached over drum axles and slide into position under the disc frame where bracket will be welded to the disc frame. When the drum and brackets are in the correct position, weld the brackets to the disc frame.
   • The crimper drums on each wing require a piece of steel tubing (7" x 7" square tubing, 8' length) that serves as the toolbar to hang the crimper drums from the disc frame. Cut notches into steel tubing at intervals coinciding with the disc frame so that the steel tubing can attach as a yoke to the frame wings. When marking where to cut the notches from the steel tubing, be sure to position the tubing so the crimper drum on the wing will overlap the center drum sufficiently. Also, remember the wing drums need to be mounted far enough back on the wing to avoid contact with the disc tires when they fold back into field position. 
   • After the notches are cut from the steel tubing, weld the brackets to the ends of the tubing.
   • Mount the steel tubing to the disc frame and tack weld it when in the correct position.
   • Roll each crimper drum under the brackets and position the axles so that bearings can be slid over the axle and bolted to the brackets.
   • Test to make sure wing drums do not contact disc tires when folding back into field position.
   • Finish welding the steel tubing to the disc frame.
10. The roller crimper is now assembled.

Objective 2: Test the ability of crimper to terminate a variety of cover crops

It was important to test the roller-crimper on participant farms to assess the durability and effectiveness of our design to terminate cover crops at scale. Therefore, the functionality of the constructed roller crimper to terminate a cereal rye cover crop was tested.

First, we tested the durability and functionality of our roller-crimper to withstand the rigors of crimping cover crops under field conditions. The crimper was used by six different farmers in seven fields during June of 2022 and 2023.

Second, we evaluated our roller-crimper's ability to terminate the most commonly planted cover crop in the region, cereal rye. To assess cover crop termination, a square meter quadrat (n = 25/field) was placed randomly within fields 5-10 days after being crimped. Within a quadrat sample, percentage killed cover crop was visually tallied.