2014 FRC's Biggest Loser

[Oblarg]

Originally Posted by magnets

First try deburring the edges. Then just sand down the hex shaft. You loose the fancy paint, but it fits!

Oh, trust me, I've got plenty of experience sanding down hex shaft. Don't exactly have enough money to just buy new bearings until we get ones that fit

[MrForbes]

huh. seventy six pounds. I guess we need to go on a high carb diet

[nathannfm]

Originally Posted by MrForbes

huh. seventy six pounds. I guess we need to go on a high carb diet

As in high carbon steel?

[DampRobot]

Originally Posted by Oblarg

Unfortunately, I have found that the probability of a vex hex bearing fitting on a vex hex shaft without issue is about 50%, though I might just have really rotten luck.

We've probably seen about forty linear feet of Vex hex shaft and hundreds of their hex bearings. Literally none of them didn't fit on the shaft properly the first time around, no filing or nothin.

[nathannfm]

Originally Posted by BoilerMentor

EMERGENCY NUCLEAR WEIGHT LOSS OPTION:

• Remove 2 CIMs from the 6 CIM drive (~7 lbs.)

If you end up a bit over and are not using them elsewhere switching 2 of the cims to mini cims will save you 1.3lb. I have heard they can be used in 3 cim gearboxes like this with the same gearing.

Originally Posted by MechEng83

On a completely unrelated note, anyone know where we can get a 26" long 1/2" keyed aluminum shaft? The longest I can find right now is 24"

MOE is unable to find one either, we may need to get one keyed with a mill, is switching to hex an option for you?

[MechEng83]

Originally Posted by nathannfm

If you end up a bit over and are not using them elsewhere switching 2 of the cims to mini cims will save you 1.3lb. I have heard they can be used in 3 cim gearboxes like this with the same gearing.



MOE is unable to find one either, we may need to get one keyed with a mill, is switching to hex an option for you?

It's an option, it would just require a little more tear-up and a few parts we don't have (but I think could acquire). I'm looking at the churro tube from AM if we go that route. My recollection is that it's loose in the hex hubs, which could cause a problem, so we'll have to check on it.

[Herbblood]

We're currently at about 85lbs. Much better than we've done in previous years

[ratdude747]

Originally Posted by BoilerMentor

With the current position HBR has found themselves in, I thought this might be a fun thing to look at.

Share your robot weight situation and describe your remedy.

Let me start by saying the number on the scale shocked me. I have 9 years of FIRST experience and I've never seen a robot look so light, but weigh so much.

Initial Robot Weight: 138.4lbs
Final Robot Weight: TBD
Anticipated Weight removal (based on list of remedies): ~21 lbs
Remedy:

• Replace 4 Mini Cims with 3 RS550's in Cimile gearboxes (~8 lbs.)
• Rebuild interface frame replacing 1/8" wall 1x1 tube with 1/16" wall (~5 lbs.)
• Replace 40" of steel 1/2" hex shaft with 1/2" aluminum hex shaft (~1.4 lbs.)
• Replace 2-1.75" bore 12" stroke cylinders with 1.0625" bore 12" stroke cylinders (~1.4 lbs)
• Rebuild intake roller with polycarbonate tubing and delrin endplates to replace 3" PVC roller (~2.2 lbs.)
• Remove excess length from any hardware or replace with a lighter option. (~.25 lbs)
• Remove webbing from the robot back plate (~2.5 lbs.)
• Remove 4 unneeded standoffs from drive modules (~.6 lbs.)

EMERGENCY NUCLEAR WEIGHT LOSS OPTION:

• Remove 2 CIMs from the 6 CIM drive (~7 lbs.)

(joking in this post)

Being 1747 alumni, I see some things never change (minus 2010).

Look at some pictures of your 2007 robot (whose name escapes me). To call that robot cheeseholed would be an understatement. It was (from what I was told at the time) accidentally made from 1/8" wall 1" square tubing (not 1/16") and even cheeseholing the frame, (if I remember right) they had to cut the tubing into angle irons to make weight. Even one frame section as cut and replaced by a carbon fiber member...

More seriously, I agree with the list... specifically the hex shaft. Usually AL is a better material than steel for hex shafts. The lone exception was the shooter shaft in Seagriffin (the 2009 robot). Being the student machinist who made the 2nd and 3rd shafts, that one had some gnarly vibrations with aluminum that steel seemed to fix. But otherwise, AL hex seems to be strong enough (although in the past, a bit less than precise when being used for pressed hubs).

[Nick.kremer]

Our 2nd year, 2012, our robot came in, 3 days before ship day, at 150 lbs....to this day I have no idea how we shed 30 pounds without sacrificing any major systems at all.

This year we are set to come in right under 90 lbs!

[Zherbert]

Weighed in on Sunday out of curiosity (it is my first year as a coach) and we only weighed 87lbs. A few more parts to add but should finish under.

[Ginger Power]

The math I did for our robot put us at around 140lbs. So we spent a whole day planning out how we would cut weight. A little over half way through the day we decided to actually weigh the robot. The scale said the robot weighed 93 lbs. Now I thought the scale had to be way off because my math is never wrong. So the my best explanation was that the weight loss fairy had come over night and taken 47 lbs off our robot. So I think 4607 is the biggest loser so far this season. Then again my math could have been wrong. But I did the math on that and the odds were that my math was right. (Obviously meant to be funny pleased don't take anything I said seriously)

[BBray_T1296]

Our CAD said the robot would weigh something like 1000lbs. But this was including a ball and bumpers that were both solid aluminum

[Max Boord]

Originally Posted by BoilerMentor

With the current position HBR has found themselves in, I thought this might be a fun thing to look at.

Share your robot weight situation and describe your remedy.

Let me start by saying the number on the scale shocked me. I have 9 years of FIRST experience and I've never seen a robot look so light, but weigh so much.

Initial Robot Weight: 138.4lbs
Final Robot Weight: TBD
Anticipated Weight removal (based on list of remedies): ~21 lbs
Remedy:

• Replace 4 Mini Cims with 3 RS550's in Cimile gearboxes (~8 lbs.)
• Rebuild interface frame replacing 1/8" wall 1x1 tube with 1/16" wall (~5 lbs.)
• Replace 40" of steel 1/2" hex shaft with 1/2" aluminum hex shaft (~1.4 lbs.)
• Replace 2-1.75" bore 12" stroke cylinders with 1.0625" bore 12" stroke cylinders (~1.4 lbs)
• Rebuild intake roller with polycarbonate tubing and delrin endplates to replace 3" PVC roller (~2.2 lbs.)
• Remove excess length from any hardware or replace with a lighter option. (~.25 lbs)
• Remove webbing from the robot back plate (~2.5 lbs.)
• Remove 4 unneeded standoffs from drive modules (~.6 lbs.)

EMERGENCY NUCLEAR WEIGHT LOSS OPTION:

• Remove 2 CIMs from the 6 CIM drive (~7 lbs.)

Time to delete autonomous! if that does not work go to a party store and request a "metric crap ton of helium"

[waialua359]

I'll never forget weighing in at 137 lbs 4 days before ship day in 2006.
We ended up chopping the top half of our robot which was a nightmare, trying to redo all the functions with a different design.

I bought car scales soon afterwards and we weigh as we build since then.

[orangemoore]

Originally Posted by Max Boord

Time to delete autonomous! if that does not work go to a party store and request a "metric crap ton of helium"

A metric ton of crap
Is still a metric ton. I don't see the difference. /sarcasm/