21-02-2008 17:26

thefro526

Re: pic: Lightened Gears

What's the weight lose on those sprockets? We use sprockets very similar to those on our drive train and they seem to weigh like 1lb each or so. It seems like lathing them down like that would shave off at least 50% of the weight if not more. Also is that gear out of the Toughbox?

21-02-2008 17:30

kevin.li.rit

Re: pic: Lightened Gears

You can always use inventor and the I-spur gear and sprocket off first cad library to estimate the weight you would save by drilling holes or turning down the hubs.

21-02-2008 17:41

MrForbes

Re: pic: Lightened Gears

or you can just calculate it, steel weighs 0.283 lbs/cubic inch

21-02-2008 17:44

Cory

Re: pic: Lightened Gears

You can take out over 50% of the weight from the AndyMark gears.

We pocketed/drilled ours, and a stack of 44 went from 19 lbs to ~8.5 lbs.

21-02-2008 17:48

thefro526

Re: pic: Lightened Gears

Dang thats alot of weight lost from those gears and im assuming that they're still just as strong

21-02-2008 19:42

Billfred

Re: pic: Lightened Gears

I'd doubt "just as strong", but I'd be receptive to a bet of "still plenty strong for our needs".

Some teams just know how to lighten up a bit in the heat of build...

22-02-2008 10:27

Wayne Doenges

Re: pic: Lightened Gears

We had our second set reduced even further. You can almost see light through the spokes

22-02-2008 10:31

MrForbes

Re: pic: Lightened Gears

We took a different approach to lightening those parts....we used the 12 tooth narrow AM sprockets on the output shafts of the Toughboxes, and we took out the second stage of gear reduction. Way less work!

22-02-2008 11:02

Racer26

Re: pic: Lightened Gears

Pff, 1075 has been lightening gears, sprockets, wheels, and any other similar objects like this for years... Last year we even went as far as to drill a 1/4" hole down the center of 5/8" bolts.

24-01-2010 16:19

Greg McKaskle

Re: pic: Lightened Gears

All very cool. But can I just point out that teams shouldn't try to lighten the cRIO. It will not pass inspection. One last year had fifty holes drilled into the magnesium cast housing. Those were some pretty expensive ounces.

Greg McKaskle

24-01-2010 17:17

engunneer

Re: pic: Lightened Gears

back in 1999, our robot had a 'net' made of 1/32" lexan strips, 1" wide. There were over a dozen linear feet of these strips. I was one of the team of students that used an industrial hole punch to knock out as much weight as possible from those strips (yes, we had gotten down to that). We punched about 2000 holes in a hexagon pattern by hand.

we also trimmed all the clear parts of our logo out of the 1/32" poly sheets they were glued to, saving another few ounces.


I also recall that we used hanging scales that year, two of them to weigh the whole robot. We were still overweight by 6 lbs a day before ship, the team went back to work trying to find more things to remove, and then I noticed that we tared the scales right side up, but used them upside-down (including the weight of the scales in the robot measurement). Since they were borrowed from the shop at the power plant, they were exactly a kilo each, so I saved us 4.4 lbs. The remaining 1.6 pounds meant the loss of a mechanism, though (we had two ways onto the puck that year, and removed one).

24-01-2010 23:31

Mr_I

Re: pic: Lightened Gears

I can't tell you how many hours I sat at our metal lathe over the years removing a pound or more per sprocket. (I feel your pain.) All that came to an end when we found IFI and then AndyMark aluminum parts. (I can still smell the burning oil ... )