In one hand you hold the soldering iron, in the other the solder, and in two more hands the parts you’re trying to solder together. Clearly this is a case where helping hands could be useful.
Luckily helping hands are easy to make, coolant hoses will do the job at under $10. Attach alligator clips to one end, mount them on some sort of base, and you’re done. Alternatively, you can steal the legs from an “octopus” tripod normally used for cell phones. So why would you 3D print them?
One reason is to take advantage of standardized, open source creativity. Anyone can share a model of their design for all to use as is, or to modify for their needs. A case in point is the ball and socket model which I downloaded for a helping hand. I then drew up and printed a magnifying glass holder with a matching socket, made a variation of the ball and socket joint, and came up with a magnetic holder with matching ball. Let’s takea look at what worked well and what didn’t.
Isn’t Open Design Great?
The ball and socket model I started with was [Alex Rich’s] Locking ball and socket arm which has design files up on Thingiverse. Why choose that one? One reason is that the ball can be locked into the socket and another is that the same mechanism tightens the socket’s grip on the ball, making the arm more rigid. Putting a ball into a socket can take some effort but it’s made easier with the help of four slots cut into the socket so that the socket can expand during assembly.
His optional twist lock ring is another reason to try this design. There are three grooves built into the socket where the ring goes. Twisting the ring into successive grooves further compresses the socket around the ball. He demonstrates the resulting tensile strength by suspending a drill from ten of them connected together.
[Alex] also included an alligator clip holder with a socket for connecting to the last ball in the arm. Luckily I already had the perfect fitting alligator clip in an old electrical clip kit, but if I hadn’t then I could have simply loaded his model into a modeling program, Blender in my case, and resized the hole. Check out the gallery on his Hackaday.io page for more photos of the locking ball system in use.
What about a base? That’s where sharing your designs and allowing others to riff on them really shines. [Alex] got his starting point from trying out [giufini’s] PCB Workstation with Articulated Arms. In there I found a choice of bases to print. And because that was [Alex’s] starting point, the balls on the bases already fit these sockets.
First Impressions and Printing A Taller Ball And Socket
Printing on my Creality CR-10 3D printer went flawlessly. The chain of arms held up the alligator clips just fine, and I was able to easily solder a wire to a switch. The arms remained in whatever shape I put them in. A little experimenting showed that there was no noticeable difference between printing with 0.25 mm or 0.1 mm layer heights.
However, my aim was also to get things up high off the table where there’d be plenty of room to work. Each ball and socket is only two cm long, which means I needed around six of them for each arm. I can see why they’re designed to be short, to make it easy to form curves. But I wanted height too so I loaded a joint into Blender and simply stretched out the center part so that the whole was four cm long. That reduced the count by one joint and I could probably have replaced another if I wanted to.
The taller midsection also meant that I could get two wrenches in place to help twist the ring to the third groove. I was printing with PLA, however, and while this sometimes worked, I did crack one socket this way. This trick maybe should be left to ABS parts.
Adding A Magnifying Glass
If you’re like me, your eyes have been around for a while and you sometimes need a magnifying glass. I found one at a dollar store that had a fair sized lens (7.5 cm) and a good depth of field. The good depth of field means that I would have a large area behind the lens where I could put things and they would still be in focus. It took less than a minute of cutting with a hacksaw at the magnifying glass’s rim to free the lens.
For the holder, I recalled seeing models for some on [giufini’s] Thingiverse page. They were the wrong size so it was back to Blender. Loading one up, I found the polygon count for the cradle portion was too high to make resizing easy, so borrowing from the basic design I drew up my own cradle. For the socket, I imported one of [Alex’s] ball and socket models, deleted the ball, and attached the socket to my new cradle. The first print showed that the lens was just a little too loose in the cradle, but a quick edit and reprint fixed that. For added robustness, I also made the cradle bulkier and upped the infill from 50% to 60% for that second one. The lens now fits snuggly and holds very solidly in place.
But it was hard to get the joints stiff enough to hold it in place at an angle. That’s no surprise given that the lens weighs in at a relatively heavy 83.5-grams. It did work, but just barely. That’s where my new four cm long joints came in handy again. They reduced the number of joints from five to three and tend to droop less. It would still be nice to find a small, lightweight fresnel lens though.
So far what I’d printed helps with soldering components together but I also do a lot of through-hole soldering with perfboards. If you’re like me, you run into the problem of trying to hold a component neatly in place on one side of the board until you can secure it by soldering on the other side of the board. At those times, my vice usually holds the board vertically so I can access both sides. That led me to the idea for another add-on, a helping hand which could be attached with magnets to the ferromagnetic vice.
I mulled over designs that included boxes for placing the magnets inside but it’s tricky coming up with a box that can be 3D printed and be closed well enough that the magnets won’t come flying out when accidentally brought near some metal object. In the end I went with magnets with holes in them which could be bolted in place. That way the box could have openings for the magnets in one face, something that’s easy to print. To keep from damaging the magnets from frontal impacts, I recessed the magnets a little inside the box.
My first attempt with just two magnets didn’t pass a rough strength test (pulling on it by hand), so I made a new one that was deep enough for two sets of two. I wouldn’t rely on it to hold the magnifying glass but it turned out perfect for holding the odd resistor or capacitor.
I couldn’t have pulled this off so quickly without the prior work to start from. The power of Open only holds up if you pass the torch for the benefit of others. The magnetic holder, four cm ball and socket, and the magnifying glass holder can all be found in a collection on Thingiverse as “remixes” of [Alex’s (alexrich82)] original models.
These helping hands work well for lightweight objects, but naturally, there is a limit. The 7.5 cm, 83.5-gram magnifying glass is at the edge of that limit. Perhaps scaling up the ball and socket to provide more resistance through friction would help there.
On the plus side, coolant hoses are reportedly difficult to disassemble and reassemble in different lengths, whereas doing so with this lockable system is easy and they won’t come apart once locked in place. But the biggest reason I’d recommend them is the ease of designing and attaching custom parts. Think Meccano or LEGO for helping hands.
Though if it’s a delicate circuit board you’re working with then a metal vice may be a little too harsh. Consider this 3D printed plastic vice that’s held shut using a rubber band which our [Tom Nardi] improved upon.