I maded it: TRex Solder 3rd Hand

TRex Solder 3rd Hand

https://www.thingiverse.com/thing:4241697

(since Thingiverse’s markdown parser seems to be broken)

Summary

A weighted, non-slip, non-wobble soldering third hand.

Huge thanks to Modular Hose for giving me the Loc-Line samples I used to make this!

Why is it called TRex? It’s got really short arms …

Despite what Thingiverse might say, this is not a Customizer project. Opening that link will disappoint.

Parts required

  • at least 12× ¼” Loc-Line segments
  • 2× Loc-Line ¼” NPT threaded connectors
  • 2× Loc-Line ¼” nozzles
  • 2× alligator clips
  • 3× adhesive round non-slip feet (up to 16 mm diameter)
  • appx. 60 g steel BB shot (or available equivalent) as ballast
  • hot glue to secure ballast and seal port in place
  • Polycaprolactone (PCL; trade names include InstaMorph) warm-melt granules to secure clips into nozzles
  • (optional) PTFE plumber’s tape.

Note that Modular Hose promotional Loc-Line keyrings each have 3 segments plus a threaded connector and nozzle, so four keyrings provide enough parts.

Assembly

  1. assemble the two Loc-Line arms with a threaded connector and at least six segments each
  2. secure the ends of the alligator clips in the nozzles using softened PCL or hot glue. Make sure that the ball joint connector surface is clear of material, as you’ll need this to fit the nozzle onto the arm
  3. fill the tool body with ballast, apply a plug of hot glue to stop it rattling and secure the end port in place
  4. Carefully thread the arms onto the tool body. NPT threads are tapered, so become gradually tighter as they go in. Use a little plumber’s tape if they’re too loose. Be careful not to overtighten, as this might crack the tool
  5. Apply the non-slip feet, applying appropriate pressure to activate the adhesive
  6. Get soldering!

Acknowledgements

Dan Kirshner’s Thread-drawing modules for OpenSCAD were used to make a nice ¼” NPT taper-profile thread. Thanks, Dan!

Foot and shot port
Side view

Data archive: TRexSolder3rdHand.tar.gz

Accessible Gaming buttons are done!

Accessible Gaming buttons are done!

Accessible Gaming buttons are done!

So in an attempt to avoid going completely shack-wacky, I made a bunch of Round Flexure Switches in my free time. I’m donating them to Makers Making Change, the charity I work for.

They are by no means in any form of corporate colour, except perhaps Lisa Frank. The tops are less tactile than I thought they’d be: the top couple of layers are gold PLA and are printed first, then the next layers are bridged above that. They’re almost imperceptible, especially after a thin layer of acrylic varnish.

The bodies are a mix of acrylic paint and ultrafine glitter, layered over with acrylic varnish to limit glitter shedding. The one that looks like a disco tree stump uses heavy gold mica flake medium. The iridescent green is unvarnished, unfinished translucent PET-G (from eSUN; perhaps my favourite material).

From a technical point of view:

  • The button nut is hot-glued in place. This keeps the top straight as a nice side effect.
  • The nuts are held in place with medium (blue) thread-lock. They won’t come apart unless you use appropriate force. Unlike red thread-lock, you will be able to take these apart for repair.
  • Digikey were out of stock on specified parts. These substitutes work directly, though you’ll have to remove a small lever from the microswitch:

I feel so seen … from 1814

So it seems my lifelong nickname is/was a Piedmontese word for noise, crash/clatter/bang or scream/shout/squawk:

[french/piedmnotese dictionary text]
Scruss s.; Bruit, fracas, cri.
La porta a la fait un scruss;
La porte a crié, a fait un cri.
from Capello, Luigi. Dictionnaire portatif piémontais-français suivu d’un vocabulaire français des termes usités dans les Arts et Métiers.. Impr. V. Bianco, 1814.

An early 19th century dictionary written by an Italian count had my number all along.

FreeCAD on Raspberry Pi 4

FreeCAD window displaying red and white traffic cone model
FreeCAD 0.18.4 running on a Raspberry Pi 4

FreeCAD and the Raspberry Pi haven’t always got on too well. For complex technical reasons the standard package would load and immediately crash on a Raspbian system. For user reasons, this was just another annoyance.

Recent releases seem to run fairly well on a Raspberry Pi 4, though, but only after building them from source. Here’s a method that got FreeCAD 0.18.4 running for me. It’s lightly modified from FreeCAD forum MartijnD‘s post:

sudo apt install cmake build-essential libtool lsb-release swig libboost-dev libboost-date-time-dev libboost-filesystem-dev libboost-graph-dev libboost-iostreams-dev libboost-program-options-dev libboost-python-dev libboost-regex-dev libboost-serialization-dev libboost-signals-dev libboost-thread-dev libcoin-dev libeigen3-dev libgts-bin libgts-dev libkdtree++-dev libmedc-dev libopencv-dev libproj-dev libvtk6-dev libx11-dev libxerces-c-dev libzipios++-dev qt4-dev-tools libqt4-dev libqt4-opengl-dev libqtwebkit-dev libshiboken-dev libpyside-dev pyside-tools python-dev python-matplotlib python-pivy python-ply python-pyside libocct*-dev occt-draw libsimage-dev doxygen libcoin-doc dh-exec libspnav-dev

wget https://github.com/FreeCAD/FreeCAD/archive/0.18.4.zip

unzip 0.18.4.zip

rm 0.18.4.zip

mkdir freecad-build

cd freecad-build

cmake -DPYTHON_EXECUTABLE=/usr/bin/python2.7 -DPYTHON_INCLUDE_DIR=/usr/include/python2.7 -DPYTHON_LIBRARY=/usr/lib/arm-linux-gnueabihf/libpython2.7.so  -DPYTHON_PACKAGES_PATH=/usr/local/lib/python2.7/dist-packages/  ../FreeCAD-0.18.4/

make -j4

Notes:

  • The only modifications I made to Martijn’s method were in the Python paths in the cmake command. Some of the paths given aren’t valid any more on an up-to-date Buster system
  • I built this on a Raspberry Pi 4 with 4 GB of RAM. It takes quite a bit of free storage: I wouldn’t attempt to build this with less than 4 GB free
  • make -j4 took 95 minutes, and even with a fan my Raspberry Pi 4 was at 70°C
  • Yes, it’s using Python 2.7, but it works
  • I’ve got no idea how to make it install properly, but it runs from the freecad-build/bin directory.

If you want to learn how to use it, look at the tutorials: even the Raspberry Pi Foundation have written some. The UK Traffic Cone model you can have: it’s what I made to learn a bit more about FreeCAD. Don’t worry, I’m still on Team OpenSCAD