Tag: Metal

Compact Keychain 2.0

The first compact keychain was a great success among my readers and became very popular very rapidly.

Now that my life has become slightly more complex, I need an extra key (and also, I’ve lost my original keychain) so I had to build another one. This exposes the most obvious fault of the design: no keys can be added or removed.

I was at the hardware store and I came across some Chicago screws, Immediately I remembered all of my readers suggesting using such screws for the keychain. Although I had seem Chicago screws previous to these suggestions, it is only thanks to my readers that now I know how they are called.

So, I decided to get some Ā¼” screws since they fit pretty nicely three keys. Since I had some extra space, I added a large washer. I can use this washer as a flat head screw driver (that even works on some Philips screws) or a bottle cap opener.

I was planning on using some thread lock in order to prevent the screw from loosen itself but it was not necessary. Also, for some keys, it may be required to enlarge their hole so the screw can fit in nicely.

Finally, while going trough a few jars filled with old keys I got form freecycle, I found an ancestor to my compact keychain. This old version features a custom Chicago screw and a leather jacket that coversĀ  the keys.

The Batrang

I always wanted to have a batrang since I have always liked Batman a lot. So, shop I decided to build one now that they have become much simpler than before in the latest Batman films.


  • A chunk of steel

The tools I used

  • Various files
  • A Jigsaw
  • A hacksaw
  • A Dremel with a heavy duty cutting blade
  • A grinder
  • A sharpening stone
  • Various grit sandpaper
  • A steel wool sponge

I used the pattern below, prescription extracted from a film poster (or something like that) and obtained by accentuating the contrast and cutting off colours until the shape was clean enough. I printed it so it measures around 3.5 cm by 12 cm.

Then, I overlaid the printed and cut shape on the metal, traced it out with a marker and cut it roughly with the hack saw and the jigsaw (the jigsaw is not mine so I mainly used the hack saw). The next step was to grind and file the metal until it had the right shape. The lasts steps where to polish it and sharpen it so it could actually cut. I prefered making it sharp than polishing, as a result, it now serves as a multi-purpose knife or letter opener. I put a magnet on it so I can stick it to other metal surfaces such as a fridge.
As my readers may have guessed, I always prefer function instead of looks.

I may try to temper it to make it stronger and more durable.

Lunar Excavator

I was lucky enough to help my friend Stephen and his team to build a lunar excavator to participate in the Regolith Excavation Challenge, hospital sponsored by NASA.

We put lots of efforts and many hours to get the robot done in time and we managed to get it running before it had to be shipped to California (from McGill University in Montreal).

Unfortunately, treatment despite the awesomeness of the lunar excavator and the fact that it was going to completely own the challenge, the UPS shipment went wrong and the robot could net get to the competition on time. Now the fight with UPS has begun to get a full reimbursement (~2000$) and the robot back.

UPS incompetence aside, I worked in putting all the electronics system together in the electrical box. This meant, I had to build two boards: one for the power management (transforming the provided 24V into a 12 and 5V in order to power the many devices and turning the latter ON and OFF), and one for the logic (interfacing the main computer with the various motor controllers and sensors).

This task was done using perfboards and lots of solder since we did not have enough time to consider designing and fabricating proper PCBs with nice places for all the components.

Note the nice (and very classy) wood finish of the electrical box interior as shown in the picture.

I will not give away any details about the excavator since it will compete next year, provided there is another Regolith Challenge.