Tag: mechanical

Recommended Tools for the New Team (and the Old Team Too)

I am a member of the VEX World Coaches Association Facebook group; if you’re a coach or a mentor, I highly recommend joining. It’s a great, friendly place to ask questions, share ideas, commiserate, etc.—about everything from running your team to buying parts to game rule minutiae. And a place to celebrate the victories, big and small. To join, log in to Facebook, and paste “VEX World Coaches Association” into the search box, and then request membership to the group.

VEX Team 3547 VirusThe coach of Team 3547: Virus has been kind enough to put together a list of must-have tools for every team, and has graciously permitted me to share it again here. The vendor RoboSource, linked here for various items, supports a VEX team; another coach from the Facebook group offered a link to the SimpleRobotics website, which shows recommended tools along with links to where you can purchase them.

First, Team 3547 recommends getting a good toolbox to preserve everyone’s sanity. Even if you have a great place to store things in your lab, some day you will need to take things to a competition or demo, and you will need some sort of carrying/organizing item. Team 3547 recommends the Dewalt TSTAK system (either the “expansion organizer” or “long handle” combined with 1+ drawer units). My team has taken a different route than the mega-toolbox, partly because their coach is a minimalist who feels oppressed by owning lots of stuff. We have a few of these Ace Hardware compartment-bins to hold our screws, nuts, VEX allen wrenches, etc., and have a zippered tool bag for the tools that don’t fit in the plastic boxes. We are, however, a one-robot team that meets in a garage. You’ll need to evaluate your own personal space considerations and team needs when choosing a tool/part organizing system.

Team 3547 Recommendations

Team 3547 next recommends the following tools, in priority order, with my comments added in italics:

  1. Ball-end Hex Key5/64” and 3/32” Ball-end Hex Key Drivers. Either get two individual drivers, or get a whole set for a little more, and you’ll be able to help assemble the field perimeter. Single drivers from RoboSource. (If you use the star-shaped/torx screws in lieu of the hex screws, they make ball-end drivers for these too.)
    If you’ve never heard of “ball-end”-anything before (I hadn’t before this year), these tools are standard allen-wrenches with a ball-nub on the end, which allows you screw/unscrew stuff, even when you are at an angle to the screw, like often happens with shaft collars in particular (feeding the wrench through a c-channel to reach something that’s not quite lined up…). While the ball-end tools that we acquired this year (not from RoboSource) worked, they lasted only a few weeks before they were stripped; each one was $9. So my overall add-on comments to this item: (a) buy high-quality; (b) only use them when the specific need arises (keep them in reserve for when a specialty tool is required).
  2. 11/32” Combination Wrench. You don’t need a whole set here, just the one size (but a couple times a year, ACE hardware sells a nice Craftsman set for $9.99). Ratcheting combination wrenchordinary combination wrenchratcheting socket wrenchsingle 1/4” wrench for standoffs. [We don’t have any of these; might be getting some soon.]
  3. Pliers and wire cutters. Good pliers are needed to pull and maneuver shafts. They are helpful to hold nuts in place to get started (especially in a tight spot), but use a wrench for final tightening. Cutters are needed for zip ties. Cheap setdecent setgood set.
    As we are a one-robot team, we can live with just 2 sets of needle-nose pliers (in the aforementioned zippered tool bag), one of which has wire-cutters set into the handle. We also just use a big pair of scissors to cut zip ties.
  4. Bent long-nose pliers. Handy for getting nuts into hard-to-reach places. [We don’t have any of these, but I can tell you that yes, they would be handy.]
  5. 11/32” Nutdriver. Like the combination wrench, only one size is needed. [Ditto]
  6. Tape Measure. [Agree 100% on this one; we got ours at Ikea for like $1.50. It is in the aforementioned zippered tool bag.]
  7. Metal snips.
    I would personally move this way up the list; we use this all the time. Shafts, 1x pieces, and my girls can easily cut aluminum L-angles without assistance (and c-channels when we’re willing to sacrifice about 1/2″ of the c-channel to bent-disasterville in the process; we usually are). (Those VEX safety glasses come in handy during build season too!)
    Instead of snips, we actually use a bolt-cutter. We used to have my husband cut things with his table saw, but this arrangement requires waiting a whole meeting day before we can move on with that part of the project (we only meet 2x/week, for big blocks of time). Being able to cut pieces right-now is extremely helpful to us. Cutting steel, however, still requires my husband to use his table saw (with special metal-cutting blade).
    A corollary to the metal snips is the metal file. We have 2 of these, and use them pretty much every time we use the metal snips (they are also stored in the aforementioned zippered bag). They are awesome and work amazingly well, especially on cut shafts that now need to fit back into a motor. One is long and flat, and the other is triangular/prism-shaped when you look at it end-on. We got both of these at our local Ace Hardware. Be sure to do all filing outdoors or in a controlled environment; metal shards and dust will result from this process.

SimpleRobotics Recommendations

From here on down are add-on suggestions from the SimpleRobotics website, with my comments tacked on.

  1. Table-top vise or c-clamp for holding metal pieces while you are cutting them.
  2. And how can you cut them without a hack saw? [Editor’s note: Good for cutting shafts and maybe 1x pieces, but I wouldn’t try to cut a steel c-channel by hand. I may be just a wimpy female here, but it seems like that would be really tiring…]
  3. A hammer. Any old hammer you happen to have around or in the back of the garage. We do pull ours out every few months, usually to push things or pry things, and occasionally to tap things together.
  4. A Philips-head screwdriver to open the top & bottom caps of the VEX motors. I think this one needs to go way up at the top of the must-have list. The SimpleRobotics website recommends a Philips #1 screwdriver, but we use a smaller size that fits the screws very well; sorry — can’t tell you the exact size. You could take a motor to your local hardware store and have the people there help you find the most appropriate one that is least likely to strip the screws. This is a really important point. These screws can strip very easily, and a screwdriver that is too small is more likely to strip it than one that is too large. Getting a stripped screw out of a motor is a pain-and-a-half. [The SimpleRobotics link is broken, FYI]
  5. Safety glasses. You’ll have to purchase these anyway for your competitions, so might as well buy them early and use them in the lab and get the kids used to wearing them. Two of my girls wear glasses, and the safety glasses for purchase on the VEX website do not accommodate them, so we went to our trusty local Ace Hardware store and bought some over-the-glasses type.
  6. Multimeter for checking battery voltage or electrical extension wires.

Another Source for Hex Keys

Allen wrenches (a.k.a. hex keys) strip. This was news to me when we started out, but one of my students showed me that if you look at one of these items head-on, that you can see it’s become a circle instead of a hexagon. This happens a lot; for the little short wrenches like you buy from VEX, the solution is to just toss them. For the long-handled (T-handled) allen wrenches, you’re talking $5-10 per item, which is a lot of money to throw away every few months.

We do what many teams out there do. One of our team’s dads has a Dremmel, and he slices off the end of the tool; the Dremmel makes a very clean cut and ta-da! you have a new (somewhat shorter) allen wrench. This method does not work, however, for the ball-end wrenches mentioned above, because if you cut off the stripped end, the ball is gone.

I and many other coaches have expressed annoyance at how lame many of these tools turn out to be. Today (November 2017) I learned of another company that sells very durable tools: MIP (Moore’s Ideal Products). The have a page devoted to VEX allen wrenches and nut drivers. Here are some reviews from other VEX coaches:

Check out MIP tools. My college team has used these for a few years and they are still like new. These are the highest quality tools I have ever used.

I was telling MIP sales about VEX Robotics and now MIP has a VEX package of tools which they sell at a discount. Sweet!


I took Andrew’s advice on MIP last year and bought three sizes plus one [nut]driver for each team. My older team took longer to accept change. It is now being the tools used by both teams. They have never shown wear. MIP has a black label set that they are promoting for black Friday. I will be purchasing more in the near future. 

My teams communicate by handing me the MIP, not the hex driver.

MIP’s VEX page includes a multi-pack wrench set, and also individual items if you scroll all the way down the page.

My Own Add-on Here

  1. Build-your-own volt-meter for about $15. This is some of the best money we have ever spent, but it requires someone a little handy with the electronics in your circle of existence. This item also came from Facebook, from the VEX Teams of the World group (you can also request membership to this group).
    • Adafruit Volt MeterFirst, purchase this component from Adafruit: the Panel Volt Meter. Cost: $7.95 plus shipping. It’s a giant digital display (1 digit to the left & 2 digits to the right of the decimal point) that just shows the voltage of whatever it’s connected to.
    • However, this item comes with just exposed red & black wires on the end, which is not helpful to connect to a VEX battery.
    • So, you need to acquire some of the plug-ends that are on the VEX smart-chargers. Luckily, this is a regular component for sale, the Tamiya Connector, Female. Cost: $2.25 plus whatever shipping they charge. We built ours from the plug-end we took off of a dead battery charger we had hanging around.
    • Here’s where you need the electrically-handy person to connect the Panel Volt Meter wires to the Tamiya Connector, Female. (a) Make sure they look at a battery that’s plugged into a battery charger to see what the red & black wires are connected to. (b) Be sure that there is a good wire-to-plug connection, or the whole thing will be a little finicky (ask me how I know this).
    • You’re done. You now have one of the most useful battery testing item in the VEX universe. Plug in a battery, look at the giant read-out, that’s it.

    This item answers so many questions, you won’t believe it. If you haven’t already encountered them, you will someday face problems like: “We’ve been driving for only one minute and the battery light is red, but we just took the battery off the charger.” Now you can test the battery lickety-split. Now you’ll know if you have a battery problem, maybe a battery-charger problem, or a cortex or wiring problem instead.

Whew! Well, that’s a pretty long list, and obviously not all of these are required items, but it’s nice to have them all written down in one place here. Tremendous thanks to the coach of Team 3547 for posting his list to the Facebook group, and allowing me to repost it here, as well as all of the other coaches on the Facebook group for all of their help and suggestions.

As promised in my last post, my next post will be more depth about Integrated Motor Encoders, and things to look out for when using them.


What Are Bearing Flats For?



Those new to VEX may be a bit mystified about these black plastic pieces called bearing flats. To start with the basics, VEX shafts (axles) have a square cross-section with slightly rounded corners. VEX metal structure pieces also have square holes that are a little bit bigger than the shaft. So you’ve got a square-ish shaft rotating around inside a larger square hole.

If you put your shaft in the motor and through a metal structure piece without a bearing flat, it will work, but it’s really not good in the long term. They rattle, make bad noises, wear out your parts in a hurry, and don’t do as good a job at transferring power from the motor to where you want it.

The bearing flats have round holes that are just big enough for the shaft to spin around in, and keep the shaft centered in that square hole in the structure piece. Smooth quiet sound, no rattling, very nice. If you have a shaft going all the way through a C-channel piece, you’ll need two bearing flats, one for each side of the C-channel (each square hole of metal with a shaft through it needs its own flat).

It’s easy in the build process to forget the bearing flats in your rush to get something working. But later you’ll have to take things apart to put them in, and no one’s happy about that. Using bearing flats is a habit that you’ll need to develop, like flossing your teeth. Bearing flats also nicely act as spacers, in the cases where you need spacing anyway. Happy building!


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