Optical cable with two LC connectors puller

TL;DR

A pulling tool for fiber-optic cables with two separate LC connectors (any pair — simplex side-by-side, declipped duplex, field-terminated). Slide the connectors into the frame, wrap everything with tape, attach pull rope with a cable tie, pull through conduit. The LC ferrules carry zero load.

Print info

Critical rules (read before printing or using)

• Use PETG or better. Not PLA.

• Wrap the printed part with tape from the connector pockets, over the entire segmented tail, and onto the cable past the end of the tail. Without this wrap, the pull force concentrates on the LC connectors and rips them off the fiber. This has happened to my prototype. Don't skip it.

• Attach pull rope with a cable tie (zip tie) through the side eyelet — never with a knot. Knots loosen, cable ties don't.

• If it gets stuck, do NOT pull harder. Back off, apply real cable lube (Polywater / Ideal / Klein / Sherman+Reilly), try again. Never use WD-40, soap water, vaseline, or generic silicone spray — all of them damage cable jackets.

How to use it (step by step)

1. Slide both LC connectors into the matching pockets on the frame, latches facing the same direction.

2. Lay the fiber cable(s) along the segmented tail.

3. Wrap tightly with adhesive tape from the frame, over every segment, and 5–10 cm onto the cable. Overlap each wrap ~50 %.

1. Loop a cable tie through the eyelet and around your pull rope; cinch it down.

2. Pull steadily and slowly. If it catches, back off — don't yank.

3. At the destination, cut the cable tie, unwrap the tape, slide the connectors out. The cable is clean and undamaged.

Material — why PETG minimum

This part is loaded in pure tension. PLA delaminates along layer lines under sustained tension and becomes brittle in the cold environments where this tool actually gets used (inside walls, underground conduit, outdoor enclosures).

Slicer settings that actually matter (OrcaSlicer — tested)

TL;DR of the print profile: Bottom shell 10 layers, top shell 7 layers, both Monotonic line. Sparse infill 50 % gyroid. Infill direction 90° (not the default 45°). Wall loops 1. That's the whole secret. Everything else can stay at OrcaSlicer's PETG defaults.

The full table for those who want to copy values exactly:

Quality

Walls

Shells

Infill

Speed

Want to understand why these settings — the deep stuff

The rest of this description is for people who like to understand what they're printing. Skip it if you just want to print the model — everything you need is above.

Why only 1 wall loop (this is non-obvious)

The segmented strain-relief tail of this model is only ~2–3 mm thick. With OrcaSlicer's default 0.45 mm wall line width:

The walls only carry hoop/radial stress on this part. The pull strength comes from the bottom shell and the directionally-oriented infill, NOT from wall stacking. Adding wall loops here actively reduces pull strength on the tail. Counter-intuitive, but tested.

Why the 90° infill direction matters — cross-ply layup

With the line / rectilinear pattern, OrcaSlicer automatically alternates line direction by 90° between adjacent layers. With my direction = 90° setting:

This is cross-ply layup — the same principle that makes fiberglass and carbon-composite laminates strong. Half the layers carry the pull; the other half hold the part together. If you forced all layers in one direction, the part would split into long parallel strands under the first twist.

If your slicer preview shows a 45° diagonal crosshatch instead of clean 0° / 90° alternation, your direction setting is still on the default — fix that before printing.

Why the tail is segmented (and why it's the most important geometry detail)

An earlier prototype of this design did not have the segmented tail. During a real pull through conduit, the result was catastrophic — the pulling force concentrated entirely on the connector pockets, the LC bodies separated from the cable's strain relief boot, the bare glass fiber was exposed, and the cable was permanently destroyed. Re-termination on a pre-fabricated patch cable is not field-practical.

The segmented tail works as a chain of short rigid blocks connected by narrow flex joints:

• Short enough to negotiate conduit elbows

• Flex joints concentrate bending into predictable hinge points

• The tape wrap forces the chain to act as a flexible-but-tension-bearing sleeve

• Pull force distributes along the entire tail length, NOT at the connector pockets

Load path: pull rope → eyelet → frame → tape sleeve → cable jacket → fiber's internal aramid yarn strength members. The LC connectors sit in the frame as passive payload, carrying zero axial load.

The segmented tail + tape wrap together prevent the cable-destruction failure mode. Both are mandatory.

License. Released under CC BY-NC-SA 4.0 — print, remix and share for non-commercial use, with attribution.

Feedback. If you use this in the field, I'd love to see photos in the "I made one" section. If you need a variant for SC, ST, or MTP connectors, drop a request in the comments.