We Made a Mistake

After spending 200 hundred hours tweaking and perfecting our innovative design, we decided to measure it in our 18 by 18 box. Never have I felt like such a failure; my family, my glory, my life’s work, all put to shame in this fleeting moment. The design was slick, frictionless linkages. Oh the linkages, they were sexy. It was a beast, powerful, fast. However, now…now it doesn’t fit in the box. I hate that box.

R.I.P B.I.S.C.U.I.T 2.0 and Christmas Break

Just because it doesn’t fit in the first time doesn’t mean you can’t make it fit - what can you trim down, rhetorically speaking? I don’t know about you, but if I were to spend that much time and then see it just tossed out the window because it doesn’t fit in the sizing box without at least trying to make it fit, I’d be ashamed. Also, planning helps.

So how far off is it? What are the final dimensions?

Ha. We did the same thing a few weeks ago. Got the design done, and it needed to be reduced in size. Stupid robot was 18.5 x 18.5 x 17. We ended up having a ton more work getting it cut down and rebuilt. I made the very last cuts today, and we’re going to pass inspection without any stress at all. Which is a really nice feeling.

Figure out what’s unnecessary and loose it. Which way are you out? Height? Because if you need to shave that down, start with the tops of things sticking out that nothing is attached to. Tops of lifts, arms, what have you. Length and width are harder. Take down extra corners, useless bits of aluminum and whatever else you can.

Mind posting a couple of pictures? We might be able to offer some suggestions.

So we had this Intake plus Launcher linkage that we built. We got rid of it and just made a fold out intake. It fits now. :slight_smile:

While yes teams are allowed to build to an 18x18x18 box it should never be so. I always suggest teams build to 17.5x17.5x17.5 so that this doesn’t happen. Always size as you build not just at the end of the build so this is avoided.

P.s As a personal pet peeve I HATE BOX HUGGERS

Sorry had to get that off my chest

Been there. It sure is a pain when you don’t realize until the competition and you spend the first half blazing through borrowed demel disks with shaking hands, attempting to saw off the edges of your robot.

I advise constantly running your robot through sizing while building it, so you can catch changes that make it not fit early. And of course be sure to do a final inspection before the competition, but it makes your life so much easier if you know before then.

I always keep a 35 hole angle next to me when building, so whenever I add a new mechanism, I can tell if I’ve gone outside size or not.

CADing your robot beforehand is also very, very useful.

That box will get you. Just always have the sizing in mind. I always built my robots using the 17.5" rails so I had something to estimate the size off of.

Spending the countless hours with sparks flying all over my legs while dremeling 5 wide c-channel… it sure does suck, but hey you get more experience with a dremel!

Trying to dremel off parts of a robot after you finish building is the worst. The only dremeling I do after building the robot now is just cutting axles. All my other metal, I hacksaw before putting on the robot. A good design process is key.

I usually leave bits of my towers extending out because they are easy to cut latter but impossible to undo later. Axles stick out of the chassis and the tower up until the point that I am sure the robot is done.

Planning is Key but I suggest being frugal.

i completely agree, cad really does help ! and i agree with sizings, never work to the 18"x18"x18"

and mistakes, everyone makes mistakes, and it is one of those things, just think at least you will learn from these mistakes

good luck

Sizing mistakes are always unfortunate… they can happen easily, too.

Some techniques to stop sizing issues before they become real problems:
*]Build your robot to be 17.5", instead of 18". When I was a participant, I only let screw-heads protrude beyond the 17.5" limit in the horizontal plane; in the vertical direction, I let us get a little closer to the limit (but not by much).
*]Size early and often. Always be checking, and then you won’t have to
*]Draw or CAD first. I, personally, find it hard to CAD the whole robot with Autodesk, because I can’t always plan out every detail before building (yet–I’m working on that!). I like to use SketchUp and graph paper to get a general idea for the maximum size of each subsystem.
*]Do the math! Sometimes, you can save yourself a lot of hard work just by running a quick trig calculation and finding that your plan would be oversized no matter how you tried.
*]If size does look like an issue, don’t scrap the whole robot. This sounds obvious, but it can be easy to forget–it is (nearly) always better to try to improve something you already have than to start over.
*]Look for ways to hinge things, if you must. The most creative usage of hinging I’ve seen in a long time was on Fred III with their pop-out omni wheels. It’s also common this year to see hinged intakes.

I’ve got to go offline… but I hope this helps some.


How often do you get explicitly told to “think INSIDE the box”?

Actually, events like this are part of the reason that competitive robotics can be so valuable. When you make a painful mistake like this, you tend to remember it… and it is relatively inexpensive and easy to fix compared to some of the mistakes you might make later in life.


Haha, my teammates were discussing the scoring mechanism and were saying how they were trying to think outside the box, to which I immediately demanded that they stop because I would like to compete with a vex legal robot. There you have it folks: Elliot’s bad share l sense of humor! :stuck_out_tongue:

But anyway, I almost always try to keep the robot within a 17.5" cube. And holy (insert your favorite expletive here), everybody agrees, this deserves a screenshot! Another piece of advice: no part on your robot should ever be longer than 35 holes, except if you’re doing an applicable arm lift