Over Weight?


Before you start cutting away you can use this calculator to find out how many holes you need to drill in 1/8" aluminum to lose a pound. One pound equates to the following:

1671 - 1/4" holes
418 - 1/2" holes
104 - 1" holes

This is just awesome! I can’t believe someone actually made this! Thanks for sharing!

When it comes to weight, the sort of mentality “Is the juice worth the squeeze” doesn’t really apply. Every little bit counts- do you use washers on your fasteners?- you don’t anymore! Can you replace a bolt with a rivet or a nylon bolt? - then do it. All these little things add up very quickly so go get your drill and a 1/2" or 9/16" drill bit and have at it! Don’t forget your deburring tool.

We removed substantial weight with 3/16 drill holes this year, almost 8000 in total. There are also about 500 2 inch diameter holes on our robot. Total weight savings were something like 10LBS, I guess it worked as this is our lightest robot in years.

To lose some weight this year, we’ve started pocketing. For those unfamiliar with the term, its basically using a mill to turn thick metal into thin metal in selected areas. It looks great, and is much more effective than normal cheese holing, because you can remove a lot more metal without greatly compromising structural integrity.

We were kinda low on funds this year, so we didn’t put any extra metal on our robot.

I would hate to be the freshman designated to deburr all those holes!

At 10 seconds per hole, that’s 22 hours to save 2.5lbs (assuming 1/8 in alluminum). Why would you spend that much time lightening an already light robot?

At 10 seconds per hole, that’s 22 hours to save 2.5lbs (assuming 1/8 in alluminum). Why would you spend that much time lightening an already light robot?

Because if you don’t you can’t compete and then you will have wasted far more than 22 hours.

Weight savings is far better by using lighter/less stuff than drilling holes.

Quoted for the truth.

Here is an excellent white Paper written by IKE that has some tips. http://www.chiefdelphi.com/media/papers/2220

Depending on your construction methods, some simple tricks can net you some big savings. Switch any 1/8" wall tube to 1/16" wall. You’ve essentially saved 50% of the weight of the tube. Go to smaller fasteners/rivets/velcro where possible. Decorative Panels and or Protective shields don’t need to be 1/8" Thick Lexan where 1/16" or even thinner will suffice. Depending on the hardware you use (This is most useful when dealing with a lot of larger fasteners, 1/4-20 or above) cut any excess threads off of bolts - no need to have 1/2" of threads sticking out of the nut.

Much of that advice is taken from IKE’s paper, but some if from personal experience. Your results may vary.

A couple of our students over the years have played ice hockey and donated their broken carbon fiber sticks instead of trashing them. Occasionally a section of it makes an appearance on a robot, just make sure it doesn’t take an impact from the wrong direction!

The entire roof assembly of our Breakway bot was carbon fiber stick as the ridge with a piece 1/32 Lexan riveted to it.