Building Habits and Techniques

Practicing good building habits is one of the most important things you can do as a VEX builder. These will make sure that your robot performs the way you want to and make it clean. First thing is to make sure that you understand and know how to use tools. Tools are your best friend when building. Most other teams have access to CNC machines or laser cutters for there parts, but unfortunately we do not. We have access to smaller tools such as Dremels, drills, bandsaws, and drill presses. You are not limited to anything; you can do anything with these tools.

Boxing C-Channels

Boxing C-channels on your team's robot is very easy and effective. As you know, C-channels have a gap in the middle of the C. For this reason, they often bend inward after wear and tear. The best way to prevent this is by "boxing" it. To do this you put a 0.875" nylon spacer in between the gap in the C. This makes sure that the two tops of the C-chan won't bend inward because they are being supported by the spacer.

Using Aluminum Only

You do NOT need steel unless it's hardware or high strength axles. There are some small exceptions to use steel on your robot, but other than those, steel is not needed. If you follow these good practices your aluminum will not bend and your robot will be fine. NEVER use steel for your robot structure. It is unnecessary to use steel because it is extremely heavy and only provides durability.

Screw Joints

A screw joint's purpose is to replace the use of an axle. Screw joints are extremely durable and provide way less friction than an axle. Many VEX teams use screw joints on their drivetrains. To make a screw joint, you put a circular brass insert into the wheel and gear on your drive. There are many tutorials out there to show how to make and even how to optimize them. Here is an example:

Nylon Hardware

Nylon screws and nuts are extremely useful in weight saving. Weight saving is such an important part in VEX building because it makes your robot lighter and faster. You want to put nylon screws and nuts in low-stress areas on your robots such as bearings or structure. You do not want them on parts that will be in constant contact or under stress. Since they are nylon, which are plastic, they will break very easily. I do not recommend putting them in hard to reach spots because if they were to break it's going to be a pain to replace.

Custom Plastic

Plastic in CAD, by Harrison Elkins.

Being able to use plastic is very helpful for building; you can make custom designs and parts that open creativity and freedom of design. Unlike previous seasons, where teams were allowed one 12" x 24" sheet of plastic to use, plastic is limited to 12 individual 4" x 8" pieces. If you are new to building and have never made plastic parts before, I highly suggest CADing out your parts. This will reduce your mistakes and make your parts cleaner in the end. Once you design them via CAD, you can either print it out on paper or 3d print the part to trace onto the plastic to cut out. To actually make the part, it will depend on the material.

• Delrin is a very clean plastic to use; many high-level teams use it. The only con with Delrin is you can NOT use tin snips to cut. Delrin cracks and shatters very easily. To cut Delrin, you will need a spinning blade such as a Dremel or bandsaw.
• Polycarbonate can be cut with tin snips. It also does not crack or shatter, only bends. I recommend polycarb for new teams until they are familiar with how to make plastic parts.

	Durability	Impact Resistance	Cutting Difficulty	Aesthetics
Delrin	Worse	Worse	Harder*	Better
Polycarbonate	Better	Better	Easier	Worse

*Unless you have a laser cutter.

Loctite

Loctite is an aftermarket adhesive which tightens a screw in a threaded part. Standoffs are the most common use for Loctite. Standoffs don't have any locking function in them. So, because of this the screws come lose very easily. I highly recommend using Loctite on screws with standoffs on your drive. The constant shaking and vibration on your drive will make your screws come loose. So use Loctite when needed.

By Samuel Lowe