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Unread 26-07-2008, 11:11
dbell dbell is offline
Mentor for team#3937 (Breakaway!)
AKA: David Bell
FRC #1519 (Mechanical Mayhem)
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Join Date: Nov 2006
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Re: pic: drive base idea

Quote:
Originally Posted by Greg Needel View Post
Just a little lesson here.

1 x1 x 1/8" aluminum tubing weighs 0.5132 lbs per foot

1x1 80/20 weighs .5097lbs per foot

so in this case your design weights more than with 80/20 now this doesn't take into account the hardware weight. Also 1x1x 3/16" is not a common size for tubing typically it comes in 1/16 or 1/8"
Thanks for the specs. I confirmed those weights here and here.

Thanks for pointing this out!

Now that i look at my CAD i realize i made a mistake. The square tubing is actually 1/8 thick, not 3/16. It was those dead axle angle brackets that are 3/16. My bad.

I guess i thought 8020 was heavier, and never bothered to weigh it. Although this design with 8020 weighs pretty much the same as a design with 1x1x1/8 tubing, the hardware is the killer. I was planning on TIG welding the square tubing frame, which adds only a very few ounces, and provides a very strong bond. the 8020 brackets are a little heavier. 12 of these brackets would weigh about 1 lb. and still probably wouldn't be as strong as a weld. Then again, a pound or two is a small price to pay for the ease of use that 8020 provides.

I'll certainly look into a direct drive for the super shifters and toughboxes.
I'm guessing this is the long shaft you were mentioning.

DB
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