Tips and Tricks

Below is a collection of tips and tricks on basic building. Some of them may seem obvious, but almost every FTC newbie made these mistakes at least once.

  • Color code your tools. If you are using several different sizes of hex drivers (e.g. 2.5 mm and 3 mm used in goBILDA), color code them, using different color electric tape for different sizes.

  • Avoid set screws. Set screws easily come loose, causing the hub to slip. In addition, set screws damage the axle, sometimes making it very hard to remove the hub later. For these reasons, whenever possible, use clamping hubs and collars instead of set screw ones. If you must use set screw hubs, use a non-permanent threadlocker such as Loctite blue to prevent them from loosening.

  • Only use locknuts. Never use regular nuts in your builds - they easily come loose under vibration. Kep nuts used in TETRIX are better, but they are still prone to loosening. For best results, always use nylon locknuts.

  • Do not use socket head screws on plastic. Using socket head screws for attaching plastic parts (in particular, for attaching servos) damages the plastic. Use button head screws instead, or use socket head screws withwashers.

  • Make sure screws are not hitting anything. When you are attaching a part, make sure the screw you are using is not longer than the depth of the threaded hole - otherwise, the screw will hit the bottom of the hole and you will be unable to tighten it properly.

    This situation commonly happens when attaching parts to a t-slot extrusion (Misumi, REV, goBILDA’s goRAIL) - if the screw is too long, it will hit the bottom of the slot, and no matter how hard you try, you won’t get a tight connection. Another case when this situation arises is when using attachment blocks where two screw holes intersect - if you are not careful, you could have one screw hitting another.

  • Do not connect two components which both have threaded holes. To get tight connection, the screw should go through an unthreaded hole in one component into a threaded hole in another, or through two unthreaded holes into a nut.

  • Removing stripped screws. A common problem is removing a screw in which the hex socket head is damaged or worn out and thus the regular hex driver doesn’t provide enough holding power to loosen the screw. Here are some ways to deal with the problem.

    • Get a better hex driver. Hex driver can also be worn out, especially ball head hex drivers. Get a new hex driver (not ball head), which is not yet worn out, and it might give you more traction with stubborn screws.

    • Put a rubber band between the tip of the hex driver and the socket. This increases the traction.

    • Use a hacksaw or a Dremel to cut a slot in the screw head, turning it into a slotted screw that can be removed using regular flat screwdriver.

    • Use a screw extractor

    • If nothing works, drill it out.

    • If that doesn’t work, remember that a screw is not a screw if it is liquid metal. This is obviously not a very good idea. :)

    Needless to say, once you removed the damaged screw, discard it immediately - do not put it back in the box with other screws.