NEED HELP - Goal Weight
 

Hi all. Hope everyone's doing well as we near the end of week two.

QUESTION 1 - Have any teams found a discrepancy between the actual weight of a goal your team constructed and the weight FIRST communicated - 181 LBS?

We constructed goals based on the BOM and updates, weighed each by hoisting onto an industrial scale, and we continually come up with between 130-135 lbs.

QUESTION 2 - If your goals do come close to 181 LBS, how did you weigh it? Are your materials the same as FIRST has specified on the prints?

Thanks in advance for the help!

John Larock
Team 365 - Miracle Workerz

Re: NEED HELP - Goal Weight
 

We (Team 811, BG-MIT/LL) built the goal and ours came up to 172 pounds. i believe we built it exactly to specification, but I don't think we were dismayed by the fact that we were about 5% off the spec' weight.

We weighed our goal by hefting it up onto a spring scale hung from an I-BEAM in the ceiling. I am not sure how accurate these scales are, but this could have been the difference right there. (Actually, now that i think of it, we did not have the retroreflective tape....but that's probably negligable)

I think your 135 lbs sounds suspect (25% lighter than usfirst claimed)....if you built it to specs, you might want to look at your method of weighing it....perhaps do some "tests" by building a 50/50 sea-saw and placing various students and adults across from a goal to see which ballpark it really live in.. ..135 lbs or 181 lbs.

Good luck,
-Quentin

if you are absolutely sure...
 

If you are absolutely sure that you are using the same stuff as the Bill of materials, and that you are not missing anything on the goals, then I suggest you still find some ways of adding weights onto the goals. Just put on whatever weights you can find to get the goals to 181lbs. I am sure you can expect the goals at competition to be this heavy, so you might as well do that to make sure your robot have the thing to test with.

The weight of the goal mostly came from the 16 steel nipples, the flanges that's holding those nipples, the steel bracket around both the deck, and the two ply wood pieces themselves... And probably all the casters. Just make sure you have all these on your goal.

There probably is a lot of variation in the weight of the pipe flanges - they were so hard to get in San Jose that we have 4
different kinds on our goal - since they probably can be a couple of ounces different in weight - this times 32 can be a 10 to 20lb
difference - same thing goes for the iron angle - if you ommitted it
or used aluminum instead - that probly id another 10 to 20lbs diff.

SO if your really worried add some weight to the bottom!

The one constructed for the Kickoff here weighed in at 178 pounds, I'm told.

We used everything exactly to spec (sadly enough even the Ralph Lauren brand paint) and ours seems to be close. i don't know an exact weight, but If your's isn't anywhere close and you're sure all of the nipples are the right distance apart and the only thing wrong is the weight, then just put some cement blocks on it or something to add enough weight. Problem solved.

RESOLUTION
 

Thanks for the responses! We went through the BOM and *almost* everything matched. We also used a different method to weigh the goals.

After all was said and done, the weight was more in line - in the 170-175 lb range.

So, we are off and running.

Hope everyone is getting *some* sleep.

-J-

As far as getting the flanges, our team lucked out. Country Depot (a store I thought only sold seed and lawnmowers) actually had them IN STOCK.

They gave us a great deal for them too.