Over Weight?
 

http://www.matweb.com/tools/weightcalculator.aspx

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

Re: Over Weight?
 

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

Re: Over Weight?
 

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.

Re: Over Weight?
 

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.

Re: Over Weight?
 

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.

Re: Over Weight?
 

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

Re: Over Weight?
 

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

Re: Over Weight?
 

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?

Re: Over Weight?
 

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

Re: Over Weight?
 

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

Re: Over Weight?
 

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.

Re: Over Weight?
 

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.