Introduction: 3D Printed Articulated Tripod

About: My name is Eammon Littler and I'm a college student interested in the field of engineering, robotics, and programming. 想像 (souzou) is the Japanese word for imagining, which I find myself constantly doing, and …

For today's project, I put together several unique techniques and mechanisms into one miniature articulated tripod. These are all original ideas and I am excited to present them to you. The tripod consists of three sections; hyperboloid ring, articulated tripod head, and phone clamp. Each takes advantage of the unique properties of 3D printing or 3D printing material; the hyperboloid ring uses printing within a 3D print to achieve a free-spinning inner ball mechanism or hinges on the tripod head using the friction between TPU filament. I will take you through the assembly process as usual as well as a deep dive of my Fusion 360 design so you can get a feel for printing tolerances and clearances needed for certain parts. Without further ado, let's build this.

Step 1: Parts

Below are the parts needed for this build. I've included STEP files for anyone wanting to make edits to the design.

  • 3/8" wood dowel x5 (cut down to any length desired)
  • 1/4" hex screw threads around 1" x1
  • 1/4" hex screw threads around 1/2" x1
  • 1/4" hex nut x1
  • 1.5 ft of 3mm ninjaflex
  • 1 ft of 1.75mm ninaflex
  • 3D Prints
    • hyperboloid ring x1
    • hyperboloid ring with thread x1
    • screw knob x1
    • tripod head base x1
    • tripod head L arm x1
    • tripod head cylinder x1
    • phone clamp base x1
    • phone clamp top x1
    • pin x2
    • 3.75mm clip x1
    • 4.65mm clip x1

* I have not tested this friction hinge design with regular TPU rubber filament. I know ninjaflex is a bit pricy, but this mechanism works with soft rubber. If you do want to try other TPU filament, make sure it has a shore rating (measure of rubber hardness) of 85A.

Step 2: Hyperboloid Ring Assembly

The reason why this is called a hyperboloid ring is because of the hyperboloid shape the three wood dowels make. Look straight on at the twisted wooden dowels and you will see two parabolas being drawn out on the sides. Imagine revolving the shape along the vertical center of the tripod and the shape you get is a hyperboloid of one sheet. The unique part of this is that twisting the rings straighten out the legs, giving you a variable twist for the hyperbola. I've made one using eight long thin wood dowels and the effect becomes a lot more clear.

  1. Thread the 1/4" screw into the hyperboloid ring using a socket wrench. Unscrew, insert the screw into the printed knob, and screw the piece in again. Using a wrench helps to establish the thread since plastic shrinks a bit when printing.
  2. Insert three wood dowels into each of the free-spinning spheres in the ring. Hot glue the ends. I don't have a better method to attach wood dowels into prints, so I'm going with hot glue for know. The dowels I got vary too much in diameter, so I can't uniformly pressure fit them into place with a standard hole diameter in the print.
  3. Insert the last dowel into the middle hole and tighten in place with the screw knob.
  4. Take the other hyperboloid ring and insert it through the four wood dowels. Try twisting the two rings in opposite directions and adjust the height of the second ring. You can feel when the rings splay the tripod legs out enough. Wherever that height is for the second hyperboloid ring, glue it down

Step 3: Articulated Tripod Head Assembly

Two summers ago, I thought about how to make friction hinges for no particular reason. I was just impressed by how our laptops manage to open so smoothly and imagined how friction plays into all of it. I'm sure they use constant force springs and sometimes gears, but my printer can't print springs or parts that small. Instead, I figured the friction contact between rubber would be enough to hold a hinge in place. Sure enough it did. Take two surfaces with ninjaflex showing on the surface and hold them tight together using a pin and clip. Varying the clip thickness would change the tightness of the hinge and also the strength. Take a look down below for the Fusion design for a better visual.

  1. Take the long piece of ninjaflex and press fit into the rings of the prints. There should be eight rings to fill. It takes a bit of force to fit the filament in, so use a pair of thick pliers to help you out.
  2. Insert one pin into the tripod head base and the L arm with the rubber rings facing each other. Take the 3.75mm clip and wedge it into the end of the pin using pliers.
  3. Insert the pin into the tripod head cylinder and push through using pliers. I'm serious, it takes a bit of force to get the pin through. Push the shorter 1/4" hex screw into the slot of the cylinder. The hex screw should rest above the pin. Do the same as step two with the pin and 4.65 mm clip for the other end of the L arm and cylinder. Both hinges should be sandwiched in place now.
  4. Take the last wood dowel and glue it into the hole of the cylinder piece. This will act as the handle for panning.
  5. Take your finished tripod head and glue it on the middle dowel of the hyperboloid tripod. If it feels loose, glue the underside too.

Step 4: Phone Clamp Assembly

The phone clamp is by far my favorite of the three sections. I've used this print for a long time and never got around to posting it. A while back, I had a flimsy little phone clamp adapter for a tripod that came free with my DSLR set. I wanted something more sturdy that I could trust and thought of ways to design my own. The biggest hurdle was the spring used for keeping the phone clamped in. I took apart my cheap adapter and saw two tension springs inside. There was no way I could print strong tension springs with a printer, nor was it worth buying. After a while, I came up with using rubber to hold the phone in place. I've used raw filament for my designs before, so I thought to do the same here. One loop of 1.75 mm ninjaflex filament is too weak, but two loops give just the right clamping force to keep my phone in place. There are two channels for the filament to slot in, adding a bit of grip for whatever tripod you attach the clamp to. A simple knot at the end is enough to keep it tight for years. For an extra layer of safety, 3mm ninjaflex inserts are added to better grip the phone in the clamp.

  1. Cut 10 small pieces of 3 mm ninjaflex rubber (size to the fitting in the clamp). Press-fit each piece into the open slots. The design is slightly different from the previous rubber fitting (in the tripod head) and doesn't require pliers to insert.
  2. Starting from the top piece of the tripod clamp, thread the 1.75 mm filament through to the bottom piece, back up again, and once more. Don't tie a knot yet. Press-fit the filament into the open channels on the bottom. Now, pull the ends taut and tie a knot.
  3. Insert the hex nut into the slot on the back of the bottom clamp. Hot glue the opening to seal it in.
  4. Screw the phone clamp onto the tripod head and you got yourself a finished tripod.

Step 5: Using the Tripod

I intend this to be a tabletop tripod, though a bit large. You can trim down the legs to make it shorter. I'm not sure of its practicality since I haven't spent much time with it, but I'm sure it'll go towards making videos in the future. This design is a bit top-heavy, so it doesn't have too much range. I haven't figured out how to splay the legs out for the tripod to compensate, but I have a few thoughts. It was really cool to finally put together a piece like this using so many unique ideas I've come up with over the years. Let me know if you figure out a good use case for the tripod or if it only ends up being a fun concept. For a concept though, there are a lot of design tricks that I reference frequently that went into this project. Let me explain below.

Step 6: Hyperboloid Ring Design

The explanation for each image corresponds to the number below (eg first explanation with the first image, second explanation with the second, and so on). Some steps from the design are omitted since they're only minor changes.

  1. Here are the dimensions for the hyperboloid ring. The clearance my printer (Prusa i3 mk3s) needed between two parts nested in on each other is 0.25 mm. The hole for the wood dowel insert is 9.75 mm.
  2. After extruding out a disc, I did a revolve cut to make the inner sphere.
  3. Instead of repeating step 2 three times, it's simpler and parametrically easier to do a circular pattern for the other two spheres.
  4. Now we have our familiar disc, but wait it's a little dense. I wouldn't want to print that.
  5. One trick I use to cut down on print time is making only the important portions of the design thicker and extrude cutting the rest. I did a 4 mm offset per circle and ring perimeter. This cuts down on print time and material while maintaining structural stability.
  6. Doesn't that look a lot better too? I think so and opted to keep it for the final design.
  7. Now for the screw thread. You need to do an initial cut, kind of like a pilot hole for wood screws, before making threads. The diameter actually doesn't matter since Fusion 360's thread tool automatically changes the diameter to meet the specified thread. I tend to size the hole similar to the diameter of the screw from my caliper measurement.
  8. Now extrude cut only on the inner section of the ring.
  9. If you watched the video, you would see the ring is actually cracked. My 1/4" screw has a threadless section towards the base that's a little thicker than the rest of the screw. I realize I didn't need threads on the perimeter of the ring and decided to cut it a wider to prevent cracking. In this case, the diameter is 6.8 mm (though 6.5 mm is probably enough).
  10. Use the built-in thread tool and choose the 1/4" ACME thread to complete the design. 3D printers are impressive, and even with a little shrinkage, they fit screws surprisingly well. They just take a bit to get going (as you saw in the video).

  11. Grips for handles are difficult to get right. I finally came up with a simple way of making them. Do a revolve cut (dept/radius of 1.8 mm).

  12. Fillet the sides.

  13. And circle pattern a number of times. It works really well.

  14. Finally comes the long hex screw. The hex head makes for really good handles in 3D printing projects. The width across flats (width of a hexagon from one flat side to the other) is 7/16" or around 11.11 mm. A half-width of 5.6 mm (full width of 11.2 mm) is enough clearance for the screw to fit in snug while having enough room to be inserted the first time. A diameter of 6.5 mm is used for the opening for the screw to pass through.

Step 7: Articulated Tripod Head Design

I really do like this friction hinge concept and plan to use it for many projects to come. In an earlier Instructables, I made a simple desk light using the friction hinge. I'm going to do an update to that design for a more rigid base and capacitive touch switch.

  1. For the friction hinge, the rubber inserts (ninjaflex filament) has to be embedded in the print very tight. For this, I find offsetting the circle cut by 1.1 mm from the surface of the print, and 3 mm in diameter works best.
  2. Make a second circle, with the same offset and diameter, and revolve cut to make the inner ring. Make a extrude cut of diameter 8 mm at the center of the concentric rings for the pin.
  3. The pin is made of three sections. The head, center, and hook. I do not have good naming conventions, I know. 2 mm for the head and 1.5 mm for the hook works fine. You may need to adjust the hook to be thicker for the clip, but it's plenty strong as is. The center (length 14 mm) will span the distance of the two pieces to be sandwiched together plus 4 mm. The L arm and base flush together in the design measure 10 mm. Add 4 mm to get the final width of the pin.
  4. Revolve to make the pin.
  5. From the middle of the center section to the hook, do a flat extrude cut. This is where the clip will sit.
  6. Measure 3 mm from the center of the back of the pin head, for a total of 6 mm in thickness.
  7. Extrude cut to make the sides flat. This will make the pin a lot easier to print.
  8. Now for the clip. An offset of 0.2 mm on both sides of the clip lets it slot in easily. If you look closely, there is a dotted line in the middle of the sketch. The bottom rectangle is simply a mirror of the top. Any changes made to the top will translate to the bottom. Noticing shortcuts like this will help when designing; especially when making edits to dimensions.
  9. This extrude is what you will edit if you want variable tension for the hinge. Extrude more for a tighter fit, or less for a looser fit.
  10. Extrude the end rectangle to act as an end stop.
  11. Chamfering the edges make it easier to get under the pin hook when assembling the parts together.
  12. Skipping to the cylinder of the tripod head, these are the dimensions for the hex screw. Dimensions are the same as the screw from the hyperboloid handle. A clearance of 5.6 mm in half flat width. The inner of the two concentric rings are used for passing the pin through and the outer for keeping the pin head below the hex screw.
  13. Create an overhang extrude to keep the hex screw in place.

Step 8: Phone Clamp Design

The phone clamp uses both 1.75 mm and 3 mm ninjaflex filaments. I only have both since I've owned printers that use the two different diameter filaments. Though most people with 3D printers probably use 1.75 mm filament, recommend having a spool of 3 mm ninjaflex on hand. It's a really good building material to have and has many uses outside of printing. In fact, I don't think I've ever been able to print with 3 mm ninjaflex. Both diameter rubber filaments have their uses, from fasteners to key holders and now phone clamps.

  1. For 1.75 mm ninjaflex, an offset from the surface of 0.6 mm creates a nice tight fit for the filament.
  2. Do a sweep cut to create the insert channel.
  3. The resulting channel.
  4. This 3 mm ninjaflex channel doesn't have to fit as tight as the friction hinge, and only needs to be offset by 0.9 mm instead of 1.1 mm.
  5. Extrude cut for rubber grip channels.
  6. I went for a looser fit for the hex nut and did 5.5 mm with a 0.3 mm offset for added clearance. This doesn't need to be a tight fit since the end will be sealed by hot glue.
  7. A symmetric extrude will make the cut easier to model with fewer steps.
  8. Symmetric extrude cut to make room for the hex nut.
  9. An offset of 0.3 mm is the clearance I use for allowing 3D printed parts to slide in and out of eachother.

Step 9: Conclusion

From print within prints, friction hinges, to rubber filament as tension springs, there is a lot to take in from this project. As I said before, I constantly open these files to get the dimensions for hex nuts or remembering what offset to make the rubber insert channels. I'm glad I finally put these together into an Instructables project. Now I can just reference these images instead of opening the large files and finding the right sketch to reference. I think the tripod turned out really nice. I tried a few new video and photo taking techniques to make my presentations a little nicer than usual. Let me know what you all think! I hope you look forward to my next project!

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