Hobby RC: Upgrading a Third Hand Tool

By Terry Dunn

Upgrading a simple helping hand with...even more hands!

I'm sure that most of us have some variation of a Third Hand (aka Helping Hand) in our workshop. If you're not familiar with this particular tool, it's basically a pair of alligator clips that are attached to articulating arms with a weighted base. The mechanical "hands" will securely hold whatever small widget you're working on, while leaving your actuals hands free to do the work. The utility of these simple tools for outweighs their meager cost (usually $5-$10).

I have several Third Hands that I employ for a variety of tasks. The one I use most often is at my soldering station. I use it to hold wires, connectors, circuit boards, motors, or whatever else I need to solder. While I love this tool, I do have to concede that it has limitations. You can certainly buy nicer and more elaborate Third Hand tools. But there is often a significant bump in price for the upgrade. Second-tier units typically sell in the $30-$50 range.

There's nothing wrong with spending $50 on a high-quality tool that fits your needs. The problem was that I didn't see any off-the-shelf models that had everything I wanted for soldering tasks. So I decided to try upgrading my base model Third Hand. This was actually my second round of modifying the Third Hand I use for soldering. I previously adapted an aluminum heatsink that makes it easier to solder battery connectors.

Firm Footing

I had previously added the large red heatsink to my Third Hand for soldering tasks, but the tool still had shortcomings that limited its usefulness.

My primary complaint about the stock Third Hand is that the base has a small footprint and is not very heavy. It tends to tip over or slide across my workbench easily when I'm soldering thick, heavy wires. I initially considered adding a thin plywood or aluminum plate to the bottom of the base. This would allow me to secure the Third Hand to my workbench with a C-clamp or spring clamp. That idea fizzled when I realized that I sometimes solder on my other workbenches…which do not accept either type of clamp.

Thankfully, I found a solution in the sporting goods department. I purchased a 2.5-pound (1.1kg), disk-shaped, iron dumbbell weight for about $2. It sits flat on its side with a much larger footprint and considerably more mass than the stock base (10oz/283gm). All I had to do was join the stock base to the dumbbell weight for a big boost in stability.

Before joining the heavy parts together, I decided to put soft footpads on the bottom side of the disk. This prevents the tool from sliding across hard surfaces too easily. You can buy self-adhesive rubber and foam pads that would work just fine. I was already in a DIY mood, so I made my own feet from 1mm-thick EVA foam. It's the inexpensive, squishy stuff that is favored by the cosplay crowd (and can be purchased at craft stores).

Using a 2.5-pound dumbbell weight as a base made the tool much more stable than the stock base. Footpads made of EVA foam prevent the base from sliding.

I cut 3 arcs of foam that matched bosses molded into the disk weight. I glued them in place with Foam Cure contact adhesive. The foam footpads provide much better friction and keep the base in position without using external clamps.

Heavy Metal

Joining the stock base to the disk weight presented a slight dilemma. I considered drilling and tapping both parts for machine screws, but that seemed like overkill. I eventually decided to take the simple route and use 5-minute epoxy. My rationale was that I could always revert back to the screw option if the epoxy didn't hold well enough. It's been a moot point so far. The epoxy is working just fine.

I adhered the components to the disk weight with 5-minute epoxy. It has been holding up well.

As you would imagine, the larger, heaver baseplate makes the Third Hand infinitely more stable. I can't imagine it tipping over during any soldering task I would ever want to do. At the same time, it is still small and light enough that I can move it between my various workbenches with no trouble. I had initially considered using a 5-pound weight, but I'm glad I chose the 2.5-pound disk. It's perfect for me.

Even More Hands

Another shortcoming of the stock Third Hand is that the alligator clips are too far apart to be useful for some applications. I could sometimes use another clip between them. The new baseplate provided an opportunity to implement just such an upgrade. It was actually easier to mount two additional alligator clips instead of only one. So, that's what I did.

I fashioned an additional clamp assembly using parts from another Third Hand and scrap aluminum.

I had some spare clips and ball joints from my LED work lamp project. I utilized two alligator clips with integrated ball joints, two ball joint plates, an 8-32 thumbscrew, and a mating wingnut. These parts were joined together to create a dual clip assembly. Even if I didn't have the spares on hand, I think it would have been worth purchasing a whole new Third Hand to obtain the parts.

The only other piece I needed to add was something that would join the dual clip assembly to the baseplate. I rummaged through my stash of scrap metal and found a short section of 1/8" x 1/2" (3.2mm x 12.7mm) soft aluminum bar stock. I think this particular bit was scavenged from a hanging file cabinet. It cuts easily with a hacksaw, so I sliced off a section about 2" (51mm) long. I added a 90-degree bend at the midpoint. My next step was to drill an 11/64" hole near one end of the bar.

The additional clips offer many more options for securing components to be soldered.

I attached the dual clip assembly to the bar by inserting the thumbscrew through the drilled hole and securing it with the wingnut. Tightening the wingnut keeps the assembly in place and increases the tension on the ball joints. My final task was to adhere the bottom side of the bar stock to the baseplate using 5-minute epoxy. I positioned the parts so that the dual alligator clips were aligned with the clips on the Third Hand.

Final Thoughts

I've been doing quite a bit of soldering with my souped-up Third Hand. The additional clips have already come in handy a few times. Of course, I can just position them out of the way whenever they aren't necessary.

Making these upgrades to my Third Hand cost only a few dollars, but made the tool much more stable and useful.

Overall, these simple, low-buck changes to the stock Third Hand have made it a much more useful tool for soldering. I should have made these mods a long time ago! I still have one more tweak that I would like to implement on this unit. Adding a small 12-volt computer fan would pull away solder fumes and make soldering a little safer. I just need to source a few parts before I begin that upgrade. Stay tuned.

If you've created or modified a Third Hand for your shop, please share details in the comments section.

Terry is a freelance writer living in Buffalo, NY. Visit his website at TerryDunn.org and follow him on Twitter and Facebook. You can also hear Terry talk about RC hobbies as one of the hosts of the RC Roundtable podcast.