This compact tripod shrinks down to tabletop size or expands up to a full-sized floor-standing unit. Each leg consists of 4 sections that lock in either the fully extended or fully collapsed position using a quick 1/4 turn friction lock. The center post has 3 sections that can be similarly extended or collapsed. Fine tuning of the height is done by sliding the whole center post up or down in the center core. The phone clamps into the tripod head with a spring-loaded finger and can be tilted and locked with a locking knob. The phone can be panned by rotating the center post in the core and locking it with a separate knob.

Note that you can get any intermediate height by not extending all leg and/or post sections. Sliding the whole center post up and down allows you to fine tune the height. The tripod is quite rigid when collapsed to shorter heights, but it becomes progressively less rigid as you start extending sections.

The Telescoping Locking Mechanism

Each extendable section of the leg has a set of ridges on the outer diameter at one end as shown:

On the inner diameter of the next larger section, there are two sets of matching grooves - one in the fully extended position and one in the fully retracted position. When assembled, twisting the movable section CCW by ¼ turn will allow it to slide up and down freely. And when either fully extended or collapsed, you can turn it back CW by ¼ turn to lock it into position.

Phone Clamp

The phone clamp will handle a wide range of phone widths. Note that if you want to use your phone in portrait mode, you can print a version of the finger with the length scaled to fit the height of your phone.

Printing 
I printed all parts in PLA for stiffness, but a CF filled filament would be even better. For greater heat resistance, you could use PETG-CF, or even better, PET-CF. The 3MF file included lumps the tripod feet in with the other PLA parts, but if you want to use this on smooth surfaces, I'd recommend printing the feet in TPU.

Print 3 copies of the Leg plate and one copy of each of the other plates.

Assembly
To complete the assembly, you will need some CA glue (superglue), two M6 nuts or two ¼-20 nuts, two M6 x 30mm bolts or two ¼-20 x 1 ¼" bolts, and one rubber band.

Leg Assembly
1. Start with the largest tube. Slide the largest ferrule/end cap over the round end and glue in place with a couple drops of CA glue.

2. Insert the next largest tube into the largest tube with the ridged end going in last (as shown in the photo above). Slide that tube all the way through the largest tube to the fully extended position and give it a ¼ turn to lock it in position. Slide the next smallest ferrule over the end of the tube and glue in place.

3. Repeat step 2 for the next 2 tubes.

4. For the last tube, slide the foot onto the end of the smallest tube and glue in place.

Core assembly
1. Position one of the legs in the pocket of the central core and press one of the small pins into the holes on either side. Is should eb a light press fit, but add a drop of CA glue of the pins seem loose. Repeat this for all 3 legs.

2. Press your nut into the hex hole in the core clamp. Note that there is a small inner step if you are using a smaller M6 nut. The bigger ¼-20 nut will just press into the larger hole. Similarly, press your hex head bolt into the knob. Thread the bolt into the fixed nut until the knob just begins to tighten.

Post Assembly
1. Assemble the post in the same way as you did the legs. On the end, though, you will be gluing on the post cap.

2. Slide the finger onto the base of the phone clamp. Loop your rubber band under the ridges in the bottom of the base and over the notch in the finger as shown in the second photo above. You may need to double up your rubber band to get a nice firm grip on your phone.

3. Assemble the 2nd knob as described above and insert it into the tilt mechanism.

4. Insert the center post into the central core.