Answered: Rule R13 and worn parts


After finally getting my team to take apart the drive system of last years robot, so we can use them for this years, we found alot of white powder. It made sense to us because a metal axle
rotating within a plastic hole will create alot of wear and tear. Once cleaned up we realized the hole was a bit larger. Not much but if you look carefully you can see it’s different from the two surrounding it. This immediately made our team think of R13, “parts are not to be modified.” We technically didn’t set out to modify anything but it’s plastic and things wear out.

Our questions:

  1. Can we use this part?
  2. If we do, What if a very detailed orientated inspector notices the difference and says our robot violates R13, How would we prove it was wear and tear and not our team getting cute?
  3. Or is this whole thing just a none issue since teams are constantly re-using parts year to year and everyone has wear?

Thank you to all that answer.

Some general wear and tear of parts over time is to be expected and would not be considered a violation of R13. The difference between “wear and tear” and a truly modified part would be when the intended form or function of the part has changed. Some examples of modified parts could include, but are not limited to:

  • Cutting a 1x8 beam down into the length of a 1x4 beam
  • Drilling through the square hole in a gear to make it a round hole
  • Heating any plastic part such that they can be bent or re-formed to a new shape

A hole in a 2x6 beam that has been worn down by a shaft is still performing the same intended function as a regular hole. On the other hand, a gear that has been drilled through is no longer performing the same function as a regular gear.

To avoid confusion during inspection, we would advise teams to avoid using worn parts in situations that would introduce any question as to if the wear and tear is affecting the performance of the part. For example, if the 2x6 beam from the previous example only has one hole with significant wear, then we would advise not using that particular hole for construction.