If you spend enough time string trimming around your yard, you'll eventually run into a place where your trimmer can not get due to the direction of rotation. If only there was a way to temporarily make it rotate the other way... I got so fed up with my picket fence that I finally sat down and figured out a way to make it happen. I apologize for not having all the before pictures. Writing this instructable was an afterthought so I'll do the best I can to describe it with the finished pictures.
First off, what will you need:
- DC powered string trimmer. I used a Ryobi model P2052 I had in the garage that I was using for light duty trimming between heavy duty trimmings with a bigger tool. Can be had for about 50 dollars at the time of writing this for the bare tool if you already have the battery in your arsenal, or 90 with the battery and charger. Other brands/models may work, this is the one that I used simply because I already had it.
- A double pull double throw switch with on - off - on configuration. 5.99 from Amazon currently.
- Some small lengths of wire and some crimp ring connectors. Spade connectors can also be used.
- Crimps... or pliers if you're in a pinch.
Step 1: Open the Housing
All the hardware we need to access is in the top of the trimmer. No need to open up the motor side.
- REMOVE THE BATTERY! Don't do this on an active circuit.
- Remove all the screws and carefully pull the housing apart.
Take a picture here if you are concerned about putting it back together.
- Remove the trigger from the housing and be ready to catch the spring.
Step 2: Find a Spot for the Switch
Depending on the model, finding a good spot for the switch might be a challenge. I found a decent spot for my switch at the place shown. Just pretend that it isn't wired yet :-)
- Remove any plastic ribs to make room as needed.
- Make a hole for the switch to poke through where you can toggle it. Don't make it oversized much or the nut won't be able to hold it in firmly.
- Plan your wire routing and remove and additional ribs you need.
Step 3: Wire the Switch
Cut the wire leading to the motor between the trigger switch and the motor. There was a bunch of extra wire coiled up inside the shaft so I pulled a bit out and gave myself a little extra on the switch side.
See the schematic attached. The basic idea is that when you throw the switch one way, it is a direct connection. When thrown the other way, it reverses the connection to the battery. This can be accomplished with a couple simple jumpers connecting the terminals.
ON MY SWITCH:
- Wire one of the motor leads to one of the top terminals (1 or 6).
- Wire the other motor lead to the other one you didn't use in step 1.
- Wire the positive battery wire to terminal 2 or 5.
- Wire the negative battery wire to whichever you didn't use in step 3.
- Jumper terminal 1 to terminal 4.
- Jumper terminal 6 to terminal 3.
Step 4: Re-assemble and Test
Put the housing back together, making sure not to pinch wires. Add the nut to the outside of the switch to hold it in place.
Test and Enjoy! Keep in mind that the string may not feed out in the opposite rotation!