I have for the most part finished my first CAD of my robot, and I am getting to a point where I need to actually see the robot in action in order to make more improvements (you can only get so theoretical). I bought a set of 6, 35 hole aluminum c channels with my own money and I don’t want to waste them. Can I cut some of them now if I feel strongly about my design (but obviously no matter how strong you initially feel there is always a chance you will change it) or should I make the robot with most of the pieces full length except just sticking out in cumbersome places? I may be wrong but I feel like the second option is just unnecessary because I may end up building the whole robot, liking it, then having to take it apart and put it back together in order to cut the pieces.
Personally, I would go with the second option since if you don’t like it then you won’t have all these random pieces of cut metal you might not use on your next design. I think it’s worth it to cut afterward, but that’s just my opinion.
I would 100% go with the second option. It is always the best practice to measure twice and cut once, or in our case build once then cut and then build again. But if you only have 6 of the piece of metal, assuming every piece is needed and there are no spares, only cut pieces that are vital to the function. If you had infinite money and c channels then I would say just cut away.
I think you should get feedback on your design from other people first (doesn’t necessarily have to be on the forum). Once you ensured that you’ve gone through the whole engineering process, take physical action. I advise only making cuts in 5 hole increments and take your time with all cuts. No jagged cuts, sand down all edges, etc.
This will preserve your aluminum as much as possible. Also, next time you CAD take design constraints into account. You don’t want to have to wait on a part to ship before you can commence building.
It depends on the subsystem. If it’s for the chassis, you might as well let them stick out until you absolutely need to cut them. You can still see the performance of the chassis with parts that stick out on an arbitrary axis. I’m not sure how much time you have on your hands, but if I were you, I’d go through multiple rebuilds to get the best final version of a design. My first comp starts in the late fall, so if you have a similar schedule, now is the best time to make many changes and build as many iterations of the design as possible. This is how true engineering is done. With many iterations and prototypes.
TL;DR don’t cut anything unless you have to
if you can build it without any cutting then you should, as long as those extra pieces don’t interfere with anything. if it ends up working really well, then you can cut them then, if not, then no parts wasted.
the best way to ensure that you aren’t going to be cutting parts in vain like @mvas said is to
okay thanks guys, it really helps to get feedback. I was overthinking it before, and I obviously should keep the pieces uncut if it doesn’t interfere with the design and I am serious about making the best robot possible.
I think you should cut the metal for the parts you think won’t be changing anytime soon, like the chassis, supports, stuff like that, and the more prototyping parts maybe don’t cut.
This early on, that is impossible to plan for.
I really like your suggestion about getting feedback from other people but I don’t know anyone as serious or invested in robotics in my area (my school team doesn’t even compete in vex sanctioned competitions… yet 
). Is it a good practice to post my entire design on the forum so everyone can see and maybe copy, or are we so early in the competition that it matters little?
Generally I discourage posting close ups on the forum because so many new teams come on here to hole count instead of learn. But, it is so early on that it doesn’t really matter if you post it on here (especially if you expect to make changes regardless). This is evident with all the CAD releases. So, yes, feel free to post on here, but don’t feel obligated to do it as you progress through the season (in my opinion).
Is it though? unless you decide to fundamentally change your robot, it’s not like everything will change. Chassis’ are easy to maintain throughout a season, and unless you’ve done something, fundamentally wrong with it, wont be subject to change?
While this is true, you can’t necessarily predict what needs to be changed on the chassis in order to facilitate other changes. Most high-level teams go through multiple stages of rebuilds and reiterations throughout the early season (which includes the entire chassis). 1727g is a great example of this because they post most of their iterations online. These teams employ high-level abstractions of the engineering process which I think other teams should work to emulate.
posting your CAD asking for feedback is a good idea imo, because while some people may want to holecount, I doubt your cad has anything revolutionary that will give any teams any sort of advantage. especially this early in the season. and as far as not posting to avoid people holecounting out of laziness, my stance is that it isn’t your responsibility as a designer to prevent people from copying you. if they do, that’s on them, and they will realize the consequences later when they have no idea how to build their own robot. I personally would post my cad here to receive feedback, and if you’re worried about holecounting, you could always do it via pm with people who give advice you value. But I think public is better so people can read the topic and learn from it.
No offense from Xenon
I strongly agree about cutting in 5 holes increments
For my tt bot i had the entire bot in 5 holes increments in fact thats how i count the length of every c channel that i have. By implementing this method as my general rule i was able to build my change up bot without cutting any c channel.
well 5 hole increments are nice, but it will severely limit you if you only use 5 hole increments.
Yeah, but under this circumstance, it will be necessary to preserve longevity of the c-channel
yeah, I agree you should keep it to 5 hole increments if you can, it just shouldn’t be a solid rule for your build.
I said “general rule”
The best time to cut the pecies is when the coach isn’t around