Introduction: Broadfork

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About: I'm a middle school science teacher going on 20 years in the classroom. I've taught 6th, 7th, and 8th graders. I'm constantly looking to improve my instruction and Instructables is one of the places I search…

The broadfork is a tool used for gardening. It is a non-inversion, aerating tool, which means it opens up the soil, but doesn't turn it over. A broadfork lets the air and water into the soil and encourages the biological life in the soil, which in the top few inches consist mainly of aerobic organisms. There have been a number of studies done covering the importance of microorganisms that live in the soil. Check out the PDF for an interesting read! Basically, we know that the little guys function to increase the soils fertility, so we don't want to mess with them if we are trying to move towards sustainability. The Broadfork allows us to till an existing bed or tear up a new one without the use of gas powered machines or animals.

Broadforks can be purchased on-line, but they can be pretty pricey. They come in a number of different sizes and styles.

My goal was to produce a Broadfork from scrap materials and items I already had laying around.

This broadfork weighs in at 18 pounds or about 8 Kg's.

Attachments

Step 1: Materials

Superstrut Metal Framing Channel

Flat steel bars

2x4's x 60" (2)

Weld-On Slipper Spring Mount

Tools used include:

Angle Grinder (cutting, polishing, and grinding wheels)

Chop Saw

Table Saw

Welder

Vise

Drill

Tape Measure

Protractor

Safety Equipment: Leather gloves, eyewear protection, welders mask, appropriate clothing

Step 2: The Step

The step (what you step on) is made of superstrut.

I cut a 22 inch (56 cm) section with the chop saw. I wanted for the step to be wide enough for me to fit between the handles.

Next, I marked where I would place the five tines. I spaced them 5.5 (14 cm) inches apart.

Finally, I cut out five notches just wide enough for each of the tines to fit through.

*Five tines is a good number for my needs. More than five would be better for established garden beds. Less tines would be more suitable for prepping brand new beds.

Step 3: The Tines

First, I used the angle grinder with a cutting wheel to cut 15 inch (38 cm) sections from a salvaged steel grate(x5).

Second, the rust and burrs were removed with a polishing wheel.

Next, I sketched out and cut a knife-like point on the bottom end of the tine.

Finally, the upper end of the tine was cut at a 30 degree angle. The angled tines are meant to help decrease strain on the users lower back.

Step 4: The Fork

This was my first time welding! It is something I am anxious to get better at. It's important to mention that the superstrut has a zinc -based galvanized coating. This should be ground or wire-brushed off the metal (a few inches back from the weld area) before welding. The grinding and welding can release zinc dust and fumes that when inhaled can make you really sick. Not to mention you get a better weld with freshly exposed bare metal.

I placed the superstrut into the vice, added the tine into the slot, and welded the tine into place. I repeated until all 5 tines were welded into place.

I then tried to clean up my spotty weld job with the angle grinder.

Step 5: The Collar and Handles

I needed a way to attach the handles to the step. I decided to use a weld-on slipper spring mount normally used for a trailer.

First, I cut two 2x4x8's down to 60" (152 cm).

Next, I ripped the two 60" 2x4's to fit snugly into the slipper spring mount. The opening for the mount is 1 7/8" (47.5 mm) so I ran the 2x4's down the table saw. I used my drill press to create the hole for the bolt.

Finally, I welded the handles and collars onto each end of the step. This was one of the hardest parts of the entire build. I wanted to make sure my handles were parallel so I couldn't just weld the mount and then add the handles. I had to weld the mount with the handles already bolted in (I wish I had a picture, but I didn't have a hand available for photos). I secured a 22 inch section of 2x4 (same length as the step) up at the top of the handles to help ensure the handles would be parallel.

*I originally chose the slipper spring mount because a wheel barrow handle would fit perfectly. Ultimately, I couldn't bring myself to spend $30.00 on two new handles when I have the ability to rip 2x4's already in the scrap pile.

Step 6: The Test

I was a little nervous about taking the broadfork out to the garden. I was afraid my weld job wouldn't hold up. I started by testing in a raised bed I've used for the past two seasons. The bed had become compacted in the off season and there is a layer of fill rock that prevented me from getting the tines to their full depth. I am happy to report that the broadfork exceeded my expectations and was so much easier than using my grape hoe to prepare the bed. It was nice to see the earth worms as I lifted the soil (worms that would most likely be killed if I was using a rototiller). Now that I know the welds are strong, I am going to paint the broadfork with a paint that will adhere to the metal and prevent corrosion. I will also shape the handles to make them more comfortable when working all of the beds I plan on adding.

Thanks for looking. Let me know if you decide to build one of your own and happy planting!

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