Fastening and Attaching

As implied by the title this post will be about fastening and attaching. Specifically for Delrin as it's our material of choice right now, so onward march to learn about how to fasten and attach this low friction and high strength material!

Heat Staking

Heat Staking: fuzing two piece of Delrin together by melting them using a thermal press. Particularly suitable for binding smaller objects to something else.
Pro: It's permanent Con: It's permanent and limited by size/shape of machine

Slots and Pegs: creating a slot and a corresponding peg (or vice versa) in the Delrin that will later be attached much puzzle pieces. Particularly suitable for cube/box-like designs.
Pro: can fasten together Delrin of any size, less machinery work
Con: it requires very high precision and is costly (in terms of material) if done wrong
To figure out the level of accuracy needed for the slot and peg method to work we use calipers to measure the tolerances which turned out to be within +/- .1cm. We also found that the solidworks figure and the real life figure were different, due to the laser cutter's slight changes per use that depend of factors such as, the time between uses and the number of times the laser has to go over the same line to fully cut through the material. It is to be noted that for future building with the laser cutter we need to overestimate for thicker materials to be more precise.

Delrin rod data

We also explored putting bushings on Delrin rods that had fits ranging from: tight, medium, and loose. Tight bushings are more suitable for a solid and permanent attachment, medium bushings are good for modeling positions without commitment, and loose bushings are useful for spinning parts.


Piano Wire: first create holes in the two pieces of Delrin with the drill press, then cut a piece of piano wire and use arbor press to put the piano wire into the holes.


Particularly suitable for hinges.
Pro: the most flexible of the three methods because it can either be a loose hinge or a tight attachment
Con: it requires lots of time, heavy machinery work and parts

An incomplete piano wire fastening