Introduction: ONE - TENTACULON

The STL files for this project are available to purchase. Just message me.


  • 0.2mm layer height
  • 2 shells
  • 10% hexagonal infill
  • cooling fan on
  • rafts/support OFF

Tendons MUST be printed with 0.2mm layer height or they won't function properly and could break much more easily.

FILES: naming protocol: assembly order_part name_quantity of each STL required

So, "7_finger_5" means this is the seventh part in the assembly order, the part name is "finger", and you'll need to print five of them.


The fit on most parts is intentionally tight so I recommend using pliers and/or a small thwacker to gently squeeze or tap parts together to save your fingers and ensure a proper fit.

I also recommend test snapping the finger bases into their sockets and removing them a few times before assembling everything. This will slightly loosen the snap-fit which will make the final assembly much easier.

PLA will loosen or soften slightly over time. At first, moving parts will be quite stiff or sticky but should loosen up and move more smoothly with a little use. I recommend moving pieces back and forth and loosening things up as much as possible before the final assembly. Once it is fully assembled, I recommend gently working the fingers and triggers by hand to make sure it's all moving smoothly and to reduce the chance of breaking the tendons.


Take special care during assembly not to kink the tendons. If you do kink a tendon, especially if it is creased, you should stop and replace it. Kinked tendons will break easily and will be the first thing to fail.

Step 1: Calibration Test

Print file "0_Test_1" at the settings listed above. This file contains a test finger and two test tendons that you'll use to ensure your settings are correct.

Make sure the tendons form a nice loop, free of kinks and bends when the ends are touched together. They should be uniformly flexible over their entire length. If they kink or break you should reprint them and you may need to adjust the print settings or try different plastic.

Make sure the finger joints can pivot freely. GENTLY work the joints loose against a table edge, turning the finger over frequently. BE PATIENT. In my experience, the joints will almost always come loose IF I'm patient and work them slowly and gently. If you try to force them they'll probably break.

If you're unable to free the joints without breaking them you will need to make some adjustments to your print settings or plastic selection.

FOR ALL SUBSEQUENT FINGERS: Once the joints are free, work them back and forth a bit until the fingers are nice and loose.

Step 2: Attach CORE to HANDLE

You've printed everything right? Got all your parts ready to go? Great!

Do whatever you gotta do to make these two parts look like the picture on the right. Without breaking anything.


Make your fingers do what my fingers do in that gif and notch the tendons (doesn't matter which end) into the triggers.

They should press fit but might need a squish against the table to fully seat.

Take care not to kink the tendons.


Align the grooves on the triggers so they're flush together (left picture) and thread them into the handle+core assembly.

Once the tendons are through, stagger the triggers - one towards the front of the handle, one towards the back - this will allow you to flex them enough to slot the trigger grooves onto the handle rails.

When properly seated, the triggers should slide freely back and forth without binding - but they might be tight or sticky at first. Slide those triggers hither and thither with gusto to loosen everything up.

Take care not to kink the tendons.

Step 5: Attach the Three CORE SEGMENTS

Slide/press the core segments down over the core. There's only one way all three core segments fit properly.

Take care not to kink the tendons

(probably should have had you do this step before threading the tendons but . . . no)

Step 6: Crack and Loosen All the Finger Joints.

GENTLY crack and loosen all of the finger joints, just like the test finger.

Step 7: Add the First Four FINGER SEGMENTS (the Last Three Segments Get Added Later)

Identify the fingertip (the smallest joint with a notch on top and bottom) and finger base (the other end dummy)

Starting from the finger base, push the fourth-smallest segment over the finger until it seats on the fifth finger joint. You may need to thwack the finger base into the segment to get it started then push/pull/thwack it over subsequent finger joints until it is in position.

Do the same with the remaining three largest segments until your finger looks like the one in the picture on the left. The finger base joint and the last three joints should be empty.

The segments should "snap" into position but sometimes it's hard to tell when they've seated correctly. The spacing between segments should be uniform and the finger joint pivot points should fall between segments, slightly towards the handle side of the gap.

Step 8: Thread the TENDONS Into the FINGER SEGMENTS

Thread both tendons at the same time ("simultaneously" for you vocabulary types) along either side of the finger, through the channels inside the finger segments.

When both tendons have passed cleanly through all four segments, seat the finger base into the core.

It's okay to flex the finger and the tendons when seating the finger but TCNTKTT.


Adjust the triggers so that the ends of the tendons align with the end of the fully seated finger.

Notch the tendons into the fingertip. Use pliers to fully seat the tendon tabs, if needed.

Don't kink nothin'!

Step 10: Attach the Final Three SEGMENTS

Press/pull the final three segments over the finger+tendons.

blah blah kink blah tendons


Remember this is a puppet at heart. Play around with it and see how it moves and behaves. If you tilt it up or down, does gravity affect how the tentacle moves? Try fast moves, slow moves, big moves, and tiny moves. Try to give it a little personality! Have fun and send me pics or gifs of your Tentaculon in action!