Lens Type: PCX, Plano Convex
Diameter: 12mm to 12mm
Focal length: 51mm to 51mm
It will get you to L4471
The lens fits in a recess in the model and is held in place with a few tiny drops of Superglue. If you get any glue on the lens it can cleaned off with nail polish remover or acetone. The lens is plano-convex (one side is flat). When inserted in the holder, the flat side of the lens faces the phone.
Note that the lens fits pretty snugly into the opening. Try fitting the lens before applying any glue. A good technique is, with the lens holder laying face-down on a table, lay the lens in position, and then push it into the recess by poking the lens with the eraser-end of a pencil. Once you know the lens fits cleanly, push it back out and put two tiny drops of superglue on opposite edges of the opening. I use a toothpick to apply the glue because squeezing the superglue directly out of the tube risks putting on too much. Then push the lens back in the same way as in the test fit.
The object pictures in the photo gallery (dime, ruler, and watch) are unedited and uncropped shots directly from my iPhone4.
This model will not slide over iPhone cases.
A smaller version of Triple Gear is available here. A baseplate and axle for using a motor to move the triple gear is available here. Also see 15 cm axle for Triple gear and 30 cm axle for Triple gear.
In this unusual mechanism three gears mesh together in pairs, and yet they can turn!

If you take three ordinary gears and put them together so that each gear meshes with the other two, then none of the gears can turn because neighbouring gears must turn in opposite directions. Triple gear avoids this problem by having the three "gears" arranged like linked rings - the gears then rotate along skew axes, and the opposite direction rule no longer applies (although see also Oskar van Deventer's Magic Gears for another possible solution).
This is joint work with Saul Schleimer. We were inspired by another of Oskar's designs, his Knotted Gear, which consists of two linked rings that gear with each other, and of course we wondered if it would be possible to do three linked rings!
Here is a paper on the mathematics behind the Triple gear, and how we designed it.
A note on materials: I have so far printed it in White Strong & Flexible only. It may arrive with the rings slightly fused together, but gently moving them back and forth will loosen them up, and the mechanism gets smoother with use. I'm not sure what effect the polishing process would have on the gearing mechanism, since it would polish the exposed gear teeth but not those which are meshed as it comes out of the printer. So I have disabled the polished material options. If you really want to try it, let me know. I also haven't tested any of the "frosted detail" materials, but I imagine that they should work fine. It isn't printable in the other "detail" materials because of cleaning problems.
Small: 3.5 x 18 x 27.5 mm
Medium: 7 x 36 x 55 mm (THIS)
Large: 14 x 72 x 110 mm
The ''Skull'' Keychain / Pendant Multitool is both a decorative as well as practical keychain accessory.
It can be used for screwing, puncturing, cutting, nail removal and even cable stripping.
It can be carried in a keychain, worn as a pendant or used as a decorative fob.
''Skull'' Multitool specifications:
Length: 2,7 cm / Height: 3,2 cm / Width: 0,3 cm / Weight: 7gr
Available in several finishes and materials (Stainless Steel, Antique Bronze Matte, Antique Bronze Glossy, Gold Plated Matte, Gold Plated Glossy). Please choose from the right.