Frame Perimeter Tolerance

[amesmich]

28" inches is 28" regardless of whats on it, however they do say things that protrude out like nut ans bolts < than 1/4" are ok so I would bet it would be ok, but thats just my bet. I would think that if you asked they would say what I said in my first sentence.

I dont think they measure to the nearest 1/16 - .0625, and I cant imagine your coat being much ticker than that? Ifs its an 1/8 thats a different story. Depend on the inspector.

Last year we used 1/4 coper tube from our compressor because of heat. We were failed even though it was not in the rules. Another team got inspected with coper and passed. We brought this to their attention and they revoked the other teams inspection cert and made them change it.(we felt bad) My point is ruels are interperted differently by different inspectors.

[Steven Donow]

[quote=amesmich;1331369]28" inches is 28" regardless of whats on it, however they do say things that protrude out like nut ans bolts < than 1/4" are ok so I would bet it would be ok, but thats just my bet. I would think that if you asked they would say what I said in my first sentence.
/QUOTE]

In regards to this, previously, I've had the "issue"(ie. it wasn't really an issue) where the LRI further clarified that that rule is simply there in respect to your own FP-ie. if you're 27.5x27.5, those protrusions are okay, but if you're 28x28, they would NOT be okay, because (as said in other posts) 112 inches is 112 inches, so no matter what you still need to fit under the 112 inches-including protrusions.

Keep in mind, this was just one LRI's interpretation, but I assume it'd be fairly consistent across the board.

[MetalJacket]

Originally Posted by DevenStonow

In regards to this, previously, I've had the "issue"(ie. it wasn't really an issue) where the LRI further clarified that that rule is simply there in respect to your own FP-ie. if you're 27.5x27.5, those protrusions are okay, but if you're 28x28, they would NOT be okay, because (as said in other posts) 112 inches is 112 inches, so no matter what you still need to fit under the 112 inches-including protrusions.

Keep in mind, this was just one LRI's interpretation, but I assume it'd be fairly consistent across the board.

That's an interesting interpretation of the rules. R2 says that minor protrusions (such as bolt heads) less than 1/4" are not considered part of the frame perimeter doesn't mention anything about those allowances being related to the rest of the perimeter. I guess in certain situations the lead robot inspector just has to make a call but that would be a situation when I would definitely want to have a copy of the rules on hand.

[magnets]

[quote=DevenStonow;1331383]

Originally Posted by amesmich

28" inches is 28" regardless of whats on it, however they do say things that protrude out like nut ans bolts < than 1/4" are ok so I would bet it would be ok, but thats just my bet. I would think that if you asked they would say what I said in my first sentence.
/QUOTE]

In regards to this, previously, I've had the "issue"(ie. it wasn't really an issue) where the LRI further clarified that that rule is simply there in respect to your own FP-ie. if you're 27.5x27.5, those protrusions are okay, but if you're 28x28, they would NOT be okay, because (as said in other posts) 112 inches is 112 inches, so no matter what you still need to fit under the 112 inches-including protrusions.

Keep in mind, this was just one LRI's interpretation, but I assume it'd be fairly consistent across the board.

Well, that inspector is wrong. The rule says "Minor protrusions no greater than ¼ in. such as bolt heads, fastener ends, and rivets are not considered part of the FRAME PERIMETER." It's very clear.

[Hallry]

Instead of asking Chief Delphi, which is as official as asking a pet goldfish, ask the question on the OFFICIAL Q&A, where you'll get an answer who know is correct: https://frc-qa.usfirst.org/Questions.php

[cadandcookies]

Originally Posted by Hallry

Instead of asking Chief Delphi, which is as official as asking a pet goldfish, ask the question on the OFFICIAL Q&A, where you'll get an answer who know is correct: https://frc-qa.usfirst.org/Questions.php

Albeit a very well informed and intelligent pet goldfish.

Stil, it's true: FIRST Q&A is the only place you'll be getting an official answer.

[Gregor]

I'd recommend you take the advice from this thread now, not on the Thursday of your competition when you'll need to do it anyway.

http://www.chiefdelphi.com/forums/sh...ighlight=frame

[Jon Stratis]

If you're going to build your robot so close to the max dimensions that you're worried about tolerance, I highly recommend bringing a big bag of candy to bribe your inspector with before he/she starts the measurement! I recommend Godiva chocolates.

[MetalJacket]

Like I said, at this point we're a little committed to our frame - I don't mean this to sound like I am ignoring people's advice. Once we have the drive assembled I will double and triple (probably even quadruple) check the frame perimeter to make sure we are legal and if needed, we can modify it.

[dtengineering]

Originally Posted by MetalJacket

Like I said, at this point we're a little committed to our frame -

And FRC is a little committed to the rule book.

Jason

[Erobot]

Its better to go safe than being sorry. For design aim to be 4 inches less than frame perimeter. If needed this will allow the robot flexible later.

[cadandcookies]

Originally Posted by DevenStonow

In regards to this, previously, I've had the "issue"(ie. it wasn't really an issue) where the LRI further clarified that that rule is simply there in respect to your own FP-ie. if you're 27.5x27.5, those protrusions are okay, but if you're 28x28, they would NOT be okay, because (as said in other posts) 112 inches is 112 inches, so no matter what you still need to fit under the 112 inches-including protrusions.

Keep in mind, this was just one LRI's interpretation, but I assume it'd be fairly consistent across the board.

That's an *ahem* interesting interpretation of the rules.

Regardless... seriously, good luck to the OP. Also:

[Cal578]

I was at an event a few years ago in which the team across from us failed inspection due to their frame being half an inch too wide. They only had 5 students on their whole team, so I sent a few of our students (and some of our tools) over to help them remake a whole lot of their robot. Very frustrating for that team (but I admired how they accepted and handled the situation).

If you have any possible way to take a quarter inch out now, I'd highly recommend it. Much better than going to your first regional with a 50% chance of failing. Maybe you can round off the corners a bit? But be careful about bumper rules...

[Al Skierkiewicz]

The recommendation from experienced (OK Old) mentors is to build to 1/4" under in every dimension. Tolerances in bending are finite and they could be too big. Whatever way the Inspection team decides to measure the Frame Perimeter, it better be less than 112". The guideline is using a 112" string wrapped around the robot frame. Boltheads, welds minor protrusions are different than a misplaced bend, angle stock in the corner or a transmission that stick outs from the frame. We call this practice "playing with fire".

[cgmv123]

I hope it never comes to this, but remember that the pits (especially the ones at Championship) can be rather toasty. Aluminum expands 12.3E-6 inches for every extra degree Fahrenheit. If your build space is rather cold like ours is (~60° F), and the pits are ~76° F, a 28x28 inch robot could gain 0.0220416 inches in its perimeter. That could cause you to fail inspection. Build smaller on purpose!

(The calculations in this post are intended as a thought exercise and are not intended to be scientific.)