pic: Team 2502 Chassis Teaser

[keehun]

loading photo ...

[Techgirl675]

looks verrrry heavy...

[firemaster193]

it seem too heavy

[keehun]

How heavy is heavy? With gearboxes, motors, electronics, the calculated weight is 50lb...

And I can lift this with one arm. Easier to lift with two arms..

[Techgirl675]

For sake of comparison our chassis with 4 CIMs, mechanum wheels and all 4 gear boxes is less than 35 pounds...
For what it's worth, we've gone the 80/20 route. While it's great for prototyping and testing, we've found it's far too heavy for competition use. We've since switched to welded thin-wall steel tubing and it seems to work quite well.

[Jeffy]

Originally Posted by Techgirl675

For sake of comparison our chassis with 4 CIMs, mechanum wheels and all 4 gear boxes is less than 35 pounds...
For what it's worth, we've gone the 80/20 route. While it's great for prototyping and testing, we've found it's far too heavy for competition use. We've since switched to welded thin-wall steel tubing and it seems to work quite well.

WOW!
4 Cims is 10 Lbs.
4 6" Mecanums is 6.2 lbs.
4 gearboxes is anywhere from 6-10 lbs.
Making your frame only
12.8 lbs. max

Our frame is pretty bare essentials out of aluminium and its at 18lbs.

[Techgirl675]

Originally Posted by Jeffy

WOW!
4 Cims is 10 Lbs.
4 6" Mecanums is 6.2 lbs.
4 gearboxes is anywhere from 6-10 lbs.
Making your frame only
12.8 lbs. max

Our frame is pretty bare essentials out of aluminium and its at 18lbs.

We have a welded steel tube chassis and it is only 10 pounds including all of the supports.

[keehun]

Originally Posted by Techgirl675

We have a welded steel tube chassis and it is only 10 pounds including all of the supports.

That's pretty cool. Though I honestly don't know why it has to be that light for it to be considered a "good" or a balanced robot

[Techgirl675]

Originally Posted by keehun

That's pretty cool. Though I honestly don't know why it has to be that light for it to be considered a "good" or a balanced robot

It really doesn't need to be, it just happens to be what we decided to use for strength and the light weight.

[keehun]

Originally Posted by Techgirl675

It really doesn't need to be, it just happens to be what we decided to use for strength and the light weight.

Haha cool. Sorry if I sounded like I hated you or something. I don't!

But someone earlier brought up low CG -- and yes, that's one of our main focuses. We are doing direct drive with Banebots Planetaries and we're trying to achieve super low CG.

[Jeffy]

Originally Posted by Techgirl675

We have a welded steel tube chassis and it is only 10 pounds including all of the supports.

Would you mind sharing the size and alloy of the pipe?
We have aluminum and steel welding machines here. and steel welding is so much easier.

[Techgirl675]

Originally Posted by Jeffy

Would you mind sharing the size and alloy of the pipe?
We have aluminum and steel welding machines here. and steel welding is so much easier.

Last year we used 1 inch steel tube and this year it is 3/4 inch with 1/2 inch supports. Everything holds up great!

[Dave McLaughlin]

One of the heftiest frames I have seen this year.

Originally Posted by Techgirl675

Last year we used 1 inch steel tube and this year it is 3/4 inch with 1/2 inch supports. Everything holds up great!

I'd be interested in the wall thickness and alloy you are using as well.

[JamesCH95]

Originally Posted by Techgirl675

We have a welded steel tube chassis and it is only 10 pounds including all of the supports.

Welded 4130 steel (maybe 1020?) is probably the lightest possible frame construction barring composites, which are cost-prohibitive for FIRST. Alloy steel is better than 6061-T6 aluminum in nearly every regard...

I've made FSAE car frames with largely .065"/0.045" walled round tubes. 0.035"x0.750" square tube would be plenty strong enough for a FIRST robot. And no strength loss from welding FTW! Unfortunately my team didn't have the facilities to make a frame like that this year

[Jonathan Norris]

Originally Posted by keehun

How heavy is heavy? With gearboxes, motors, electronics, the calculated weight is 50lb...

And I can lift this with one arm. Easier to lift with two arms..

Trust us you'll be surprised how weight seems to adds up... fair warning just make sure you are careful how heavy the rest of your robots functions are.