June 21, 2026
Description
Ever encounter encounter a the problem where you are holding the end of some filament and it slips out of your grip, back into the container or PTFE tube you were working with and now have to break things down, open them up, and fish the end back out? I certainly had, but with starting to use auto-rewind spools that became a very common occurrence.
To battle that I designed this small (0.73g-0.84g for the simplest) filament clip meant to sit on top of PTFE tubing and use a cam-latch to lock in and keep filament from slipping through. Easy to slip on and clamp, and easy to remove or just loosen when needed.
Since different situations might call for slightly different solutions, there are three variants:
The minimal clip/grip that sits on top of PTFE tubing (or just a fitting or hole directly) and latches. This version takes only about 0.73g-0.84g of filament each.
A version with a modified bottom that takes the work I did for locking collets and allows the clip/grip to be locked onto the end of a section of PTFE tubing.
A version with collet locking on both ends. Useful if your existing setup feeds filament with PTFE tubing protecting it along the way.
There is also a matching cap that should fit down onto the open end and includes a thinner section at the top that should hold onto filament slightly. It was also designed so it fits over PTFE tubing, but if you want to fit snugly onto just tubing, without the grip, then it might need some print tuning. The caps should be printed in TPU or some other such flexible filament.
FreeCAD sources are included, although the FilamentGripLocking.FCStd file does require the PTFEHolder.FCStd file that can be downloaded from my CC1 CANVAS remix.
All parts should be printed in their provided orientations.
0.2mm layer height
supports on (the minimal clip should not end up using any)
I've included .step files because they give smoother results with smaller files as long as your slicer (such as Orca Slicer) supports them. The .stl versions are included for those who need them for their workflows, but are normally of a poorer quality due to tessellation being baked in.
Do not be fooled by the Printable's 3d preview. They recently added support for .step files (nice!), but run their preview conversion at a much lower quality than Orca slicer and its ilk use when opening .step files. So it is still better to use the .step versions if your slicer supports it.
The should be assembled into the grip using a piece of filament for the hinge.
Once the pieces are printed, you might want to ensure the vertical path for the filament is large enough by using a pin vise/mini drill with a 1.75mm or 1.8mm bit to clean it up. Try not to enlarge it more than needed to allow filament to slide through, as the cam will need to press the filament up against the far side.
If needed, the hole in the cam can be cleaned up, but do not make it so large that filament slides through easily. You want to end up with it holding the filament fairly tightly. (I normally use a pair of needle nosed pliers to hold sideways close to the cam and push the filament into place.)
hold the cam in place with the "thumb" up and towards the outer part of the grip and the larger part of the cam towards the center. Line up the holes in the grip with the hole in the cam
slide a piece of filament into one side, going first through a side of the main clip body and into the side of the cam that was facing up on the build plate might work best
firmly push the filament into and through the cam until it goes fully out the other side of the grip. If it is a very tight fit, try holding the filament with a pair of needle nosed pliers with only a small distance between the pliers and the grip
push and tap until the filament is at least in place
use flush cutters to trim any filament extending past the outer walls of the grip
If you want to block the openings a little more on the versions that use a PTFE collet, look at the GripBootA and GripBootB models. The A is for either variant with one or two collet ends, and the B model is for the variant with a collet fitting on either side. It is recommended to print these with PETG, as TPU is normally a bit too soft to hold shape.
Latching filament into the grip should be quick and simple:
being careful not to lose hold of the filament, push it from below up through the grip. Be sure that it exits from the top, and not the cam opening on the side
if using a cap
push the cap down onto the filament until that fits down all the way and reaches the end of the smaller section
gently flip the cam towards closed, aka with its "thumb" moving in towards the filament, but leave it loose enough for the filament to still move
gently slide the filament with cap down onto the grip, where the cap should push the cam down, locking it tight
finish by pushing the "thumb" towards the filament to ensure it is fully locked in place
if not using a cap
slide the filament up or down until you are happy with the amount extending above the grip
flip the cam closed, pushing in on the "thumb' to ensure it is locked firmly in place
After latching it closed, gently pull on the filament below to test that it holds. Remember, it is designed to hold against a retracting spool or just falling in, not a full-strength human pull.
To release the filament, remove the cap (if used), hold the end of the filament to prevent it sliding back down, and then open the cam latch by levering the "thumb" up and out away from the filament.
License:
Creative Commons — Attribution
7
joncruz
