Hand-weeding tool designs from Al Dong

Make Your Own Weeding Spade

By Allen Dong, I-Tech, PO Box 413, Veneta, OR 97437

This invention was declared public domain on February 15, 1996, a gift to humanity.

Here is a design for making a hand held weeding spade to weed between plants, such as a bed of garlic. The weeding spade was made from a masonry "pointing" trowel (Figure 1) by notching and sharpening the edges of the trowel. The advantages of using a "pointing" trowel to make the weeding spade include:

High quality towels have very strong and hard blades made of tool steel that cannot be sharpened with file. A high quality trowel will hold a sharp edge better than a hand hoe blade that can be sharpened with a file.
Compared with a hand hoe, less effort is required for working a trowel blade below the soil surface because the towel blade is thinner. For example, the Marshalltown pointing trowel blade (model 45-5 and 45-6) is 0.05 inch thick near the handle and 0.025 inch thick near the point; compared to the Ames hoe with a 0.1-inch thick blade.
The "pointing" trowel blade provides both a narrow edge and a broad edge for weeding between plants.

Grind notches (1/8 inch wide, spaced 3/4 inch apart) on the edges of the trowel using an angle grinder (Figure 1). The notches permit hooking and tearing of the weeds. The edges of the trowel are beveled sharp with an angle grinder, or a grinding wheel. Be careful not to grind the blade at one spot for an extended period (more than 1 second). Otherwise heat will build up, changing the steel color to blue and the steel may become brittle at that spot. The grinding can also be done at shops that sharpen knives, scissors or saw blades. Cost of a six-inch masonry "pointing" trowel is $3-10, depending on quality of steel, thickness of blade, and manufacturer.

Figure 1. Angle grinder for modifying the trowel; masonry "pointing" trowel; and a weeding spade.

Acknowledgement: Technical assistance from Emeritus Professor William Chancellor, University of California, Davis and Roger J. Edberg, University of California, Santa Cruz, CA.

Serrated Hand Hoe and Mower Blades

By Allen Dong, Jane Edberg and Roger J. Edberg, I-Tech, PO Box 413 Veneta, OR 97487

This invention was declared public domain on August 5, 1991, a gift to humanity.

The hand hoe uses a sharp straight edge to cut plant roots and stems. The hoe can be improved by grinding slanted grooves on its cutting edge (Figure 1). The grooves give a serrated edge to the hoe and keep the plant from sliding out of the cutting edge as it cut and tear. This modification can be made with a hand-held electric disk grinder or stone-grinding wheel.

A hand-held electric disk grinder with a 4 1/2 inch (114 mm) diameter by 3/16-inch (4.8 mm) thick grinding disk is used (Figure 2). The grooves are approximately 1/32 inch (0.8 mm) deep by 5/8 inch (16 mm) long, spaced 1/2 inch (13 mm) apart and ground on the flat side of the hoe that faces the person. Compared with the beveled side facing the earth, grooves ground on the flat side of the hoe will not wear out as quickly and the grooves are not ground off when the blade is sharpen on the beveled side. The grooves are slanted away from the hoe handle. Slants on the left side of the hoe are mirror images of the slants on the right side of the hoe. This modification can be made in less than 2 minutes.

Other applications of serration include rotary mower blades (Figure 2). For lawn and rotary mower blades, the grooves are ground on the flat side of the blade, perpendicular to the cutting edge and are spaced approximately 5/8 inch (16 mm) apart (Figure 2). After grinding the grooves, the mower blade must be balanced to reduce vibration during use of blade.

Acknowledgements: Technical assistance from Emeritus professor William Chancellor, University of California, Davis and Phyllis Woodbury, Lorane, OR

Top Figure. Hand hoe with grooves.

Bottom Figure. Rotary lawn mower blade, 500 mm (20 inch) (A), rotary mower blades for 1.27 m (50 inch) cut (B), and hand held disk grinder.