Disc Brake Rotor Becomes a Monster Weed Puller

Agave is a great low-maintenance plant for our climate. But it still needs some grooming periodically, and it sends out pups that will take over if not removed. Some of mine got too big to easily pull by hand and my store-bought weed puller couldn't budge them without bending. Enter the monster. I decided to make a weed puller so stiff it would never bend...

Angle Grinder

Cut off disc

Drill Press

Vise

1" x 48" gas pipe

1" FPT Steel coupling

Welder

Face Shield

Dust Mask

Used brake disc rotor

For this step, wear a face shield and dust mask.

I had a couple of old brake rotors that had been replaced on our family car a while ago. In them I saw my weed puller. The first photo shows a complete rotor and the fully cut rotor side by side for comparison. I used the angle grinder to cut the two tines from opposite sides, then the center piece and two spacers from the rest as shown.

I needed to firmly weld a pipe fitting into the center piece, so I marked it to fit in a notch with plenty of steel on both sides for welding. I drilled along the bottom of the notch to make it easier to cut the rest of the way with my angle grinder.

I hit the coupling with a wire wheel to remove the galvanized finish in the vicinity of the weld. I adjusted my notch with the angle grinder to get a tight fit on the coupling prior to welding.

There are instructables by much better welders on the subject of welding. I will just say that after it was all done, this tool worked like a champ with no issues whatsoever. I tacked my pieces in place and used a vice and clamps to hold the pieces together while I went around all the edges of all the joints to get the best bond. I turned up my little wire welder to its max current because these pieces are thick compared to what I usually weld with it. Other welders would need other settings.

This shows my tool as welded and screwed onto the pipe that serves as a handle.

After I scrubbed off the flux with wire brushes and cleaned up what was left with acetone, I primed and painted the tool to inhibit rusting.

I recorded my first use of the tool and posted this video. I found that the tool is quite heavy, which takes some effort to swing, but is very satisfying when it bites into the roots of the plant I'm pulling. I learned it takes some practice to aim and get under the roots, but once I get it, prying those tough old agave pups out was a joy. Once removed, the pups were even in good enough shape to be replanted somewhere else.

Thanks for checking out this Workshop Revival project. If you enjoy turning scrap into tools, follow me on Instructables for build details and subscribe on YouTube to see these projects in action. I’ve got more builds on the way — thanks for being here, and keep making new stuff out of old stuff that earns its keep!