terraPin High-Strength Winder (1/4" shaft)

by schlem, published

terraPin High-Strength Winder (1/4" shaft) by schlem Jun 22, 2017


Ever since my original P6*6 3D printed pinhole camera, the weakest links in the film transport were the spade-shaped winders that press-fit into a slot in the knobs. Occasionally, the stress of winding film (jams, poor fit, curved film plane, etc) would necessitate a little oomph on the knob, and - SNAP - the winder would break. This is a huge pain in the neck.

I noodled on this a lot. At first, I explored having the original part custom-made in a stronger material, but I quickly realized that I could redesign the winder to use a standard industrial control knob for a 1/4" (6mm) shaft (or even an electric guitar knob with a set screw). There is a multitude of knobs that will work with these winders. NOTE: I file/sand the bottom of the knob smooth to prevent it from grinding on the top of the camera.

I used Shapeways to make the first version and iterated them several times to get them right. I use them on all the cameras I sell (I have different winders for the OSKAR camera knobs). I adapted that winder design and optimized it for FDM production.

These winders come in two lengths (12mm and 14mm) for optimal set screw placement - not too close to the end! They also have a shape that requires support. I HATE designing things that can't be printed without support, but these doodads are small enough that the clean-up only takes a minute. I tried to design my own support structures, but I couldn't compete with the intelligence of the Slic3r support algorithm. The winders are oriented on the print bed for maximum strength, and I print them at fine layer height with infill >70% for lots of torsional rigidity and set screw bite. The walls at the ends of the overhangs minimizes warping and distortion. You might need to do some shaving with an X-acto for a precise and flush fit.

These winders will work with these cameras:
terraPin OSKAR Lochkamera (pinhole camera)
terraPin OSKAR Tuxedo 6X9 Lochkamera
terraPin ACME 6X6 (6x9, 6X4.5) Pinhole Cameras
terraPin Prime 6X6 Pinhole Camera
terraPin 2HT Stereo Pinhole Camera
terraPin Kaiju 6x18 Pinhole Gamera
terraPin, a 120 Film Pinhole Photography System
terraPin 6X9 120 film Pinhole Camera
terraPin Bijou 6 x 4.5 Pinhole Camera and Sidewinder version
and the original P6*6 120 Pinhole Camera

I buy heavy-duty industrial knobs from Mouser Electronics. They aren't too expensive, and the white index mark comes off with a swipe of acetone or nail polish remover.
If you don't want to (or can't) print these winders yourself, you can buy a pair from Shapeways. They will be vastly stronger than the original FDM press-fit winders/knob in the Thing files. They have a 1/4" shaft and they don't twist off like the original design. You may need to trim 2-3mm off the shaft if your knobs aren't deep enough -use an X-acto blade, with small bites.

You can also get the winders 3Dprinted in METAL by Shapeways!! They're spendy, but they're like jewelry! Zombie Apocalypse Bomb-Proof.

For the OSKAR LochKameras, there is a similar winder available from Shapeways, with a hex-shaped shaft for the OSKAR knobs.

This work is licensed under the Creative Commons - Attribution - Non-Commercial license. This license applies only to the files and documents available for download from the Thing Files section of this Thing.
All other related content (photographs, videos, and verbiage such as contained in "Description" or "Instructions" ) are excluded from this license, with all rights reserved, unless specifically available for download This notice constitutes a clarification, not a change, to licensing for this design.

Print Settings

Printer Brand:




Doesn't Matter




0.15 mm layer height


HIGH > 70%



I twist off the support with a pair of needle nose pliers. An X-acto blade comes in handy for removing stray support and any irregularities that interfere with fit. Pay attention to the ends of the winder where the support wall attached - it never tears off cleanly. Depending on the precision of your support structure, you may need to shave the shaft to a rounder shape to fit the knobs. Not too much!

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