2014 FRC's Biggest Loser

[magnets]

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.

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


As for the long shaft source, you could go with McMaster, which sells some .500 aluminum rod with the "ground and polished" finish. This will be the exact diameter, but doesn't have the keyway cut into it. You could then cut your own keyway, use a roll pin, or make some flat parts on the shaft, and use a set screw.

[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?

[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

[Master Mac]

Our Robot , yet I=to be named from Team 1075 weight is about 92 lbs all in. We have 4 Cim " not be release " hardly ever seen style of drive with interior tough box gear changes 14 and 24 tooth. we use 2 more cims for shooter our ball, one fisher price for ball pick up along with 2 van motors for the arm mover. base frame id 1by3 tube 1/8 wall, arm is 1x1 channel, removalable shooter frame is 1x2 channel, arm is 1x1 channel and tube. WE control everything with 7 Talons ( Expensive ). I think the secret is our welding student who can held aluminum like no tomorrow. Pics later in the week. Good luck teams.

[Michael Yeh]

Our robot hit 110 lbs on a very old bathroom scale today, which is almost exactly what our CAD said. We plan to acquire a better scale, but we had some people with known weights "calibrate" that one. Our structure is pretty simple but is mostly heavy 2x1x.125" tubing and we're using all 6 CIMs, 4 miniCIMs, and a pair of AM 9015s on the PG-71 gearboxes (no, we don't plan to pop the breaker every match )

The tubing is mostly solid so we may try to make some sort of jig to swiss cheese our unbagged parts. Life would probably have been much easier if we used the thinner Vex tubing, but they were out of stock until the day we placed our order. We may also switch out the miniCIMs with banebots motors in versaplanetaries or CIMiles if we can afford it.

[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.

[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.

[piersklein]

Rookie team here and we WAY over built (the team takes durability way too firmly). We are at 110lbs and do not shoot. We are using 3 by 1.5 in double extrusion for arms which weigh in at 50 lbs. And do not have much to save weight in. On the plus side, we can *accidentally* be a battering ram.

[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/

[Pault]

Originally Posted by orangemoore

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

Well, if you want to get technical, helium doesn't have negative mass, it is just less dense than air. A metric ton of helium is a metric ton of stuff, but it's still gonna float.