Gravity Vehicle C

Locked
User avatar
mrsteven
Exalted Member
Exalted Member
Posts: 815
Joined: March 13th, 2011, 5:40 pm
Division: C
State: IL
Location: UIUC (Formerly BGHS)
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by mrsteven » March 19th, 2013, 7:43 am

I've tried to remove CA glue from open bearings before. I eventually got it, but it took an exuberant amount of time, and like balsaman said, it never really was back to good as new.
Trying to remove epoxy from the bearings would prove near impossible and won't be accomplished with just acetone. I think its a worth cause to just buy a new one.
The only reason I tried to salvage the bearing was because it was one I used for gravity vehicle but got glue in it, so it went into my graveyard of assorted parts. I needed it for maglev to be somewhat free but that extra friction from the little glue left was actually desirable so thats why I tried to flush it out.

$3 for the bearing vs 3 hours of your time? Its worth while. Let alone this event really comes down to friction reduction so that little friction left in the mostly-salvaged bearing will change your scores somewhat dramatically, I fear.
2011 Helicopters State Runner-up
2012 Helicopters State Champion
2013 Robot Arm State Champion

iwonder
Admin Emeritus
Admin Emeritus
Posts: 1112
Joined: May 10th, 2011, 8:25 pm
Division: Grad
State: TX
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by iwonder » March 19th, 2013, 7:58 am

$3 for a bearing? :O
'If you're the smartest person in the room, you're in the wrong room' - Unknown

catfoot
Member
Member
Posts: 10
Joined: December 6th, 2012, 4:24 pm
Division: C
State: AZ
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by catfoot » March 19th, 2013, 9:58 pm

Alright thanks for the advice everyone, new bearings it (probably) is.

Also, as iwonder said, $3 bearings? Hook me up! o_0

Also (again), does anyone have advice for how to secure the bearings to the vehicle and also to the axles? Seeing as my previous application technique is clearly flawed, I definitely need help.

User avatar
mrsteven
Exalted Member
Exalted Member
Posts: 815
Joined: March 13th, 2011, 5:40 pm
Division: C
State: IL
Location: UIUC (Formerly BGHS)
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by mrsteven » March 20th, 2013, 5:17 am

.... Umm ya. $3, why what are you guys spending for them? I get all my tech-type-supplies from mcmaster carr so I got 1/4 inner D open flanged ball bearings for 3 a piece.
The flange helps to keep everything square. When you pound the bearing into place the flange keeps it flush with the surface. Therefore, as long as the holes for the bearings are exactly straight from each other and the 2 axles run parallel, it goes straight.
To ensure that, I printed my chassis :D

Securing to the vehicle? Cut the holes the same size as the outer D of the bearing and arbor press it in.
Bearing to axle? I used CA glue havent had an issue ~100 runs later
2011 Helicopters State Runner-up
2012 Helicopters State Champion
2013 Robot Arm State Champion

iwonder
Admin Emeritus
Admin Emeritus
Posts: 1112
Joined: May 10th, 2011, 8:25 pm
Division: Grad
State: TX
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by iwonder » March 20th, 2013, 5:29 am

Are these ABEC rated bearings or just conveyor-belt ones with a lot of play in them? I used some ultra cheap bearings from McMaster Carr for a floating arm trebuchet and I wouldn't use them again :P

I got my bearings for $15 a piece from Stock Drive Products, they're ABEC-3(tight tolerances), flanged, with an extended inner race(so shaft collars don't cause more drag), I also got pillow blocks to mount them in for that price.
'If you're the smartest person in the room, you're in the wrong room' - Unknown

User avatar
mrsteven
Exalted Member
Exalted Member
Posts: 815
Joined: March 13th, 2011, 5:40 pm
Division: C
State: IL
Location: UIUC (Formerly BGHS)
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by mrsteven » March 20th, 2013, 7:21 am

iwonder wrote:Are these ABEC rated bearings or just conveyor-belt ones with a lot of play in them? I used some ultra cheap bearings from McMaster Carr for a floating arm trebuchet and I wouldn't use them again :P

I got my bearings for $15 a piece from Stock Drive Products, they're ABEC-3(tight tolerances), flanged, with an extended inner race(so shaft collars don't cause more drag), I also got pillow blocks to mount them in for that price.
they're very nice bearings. I have never had issues with bearings from mcmaster carr. We use them for our combat robots, so they definitely can take a punch and continue working
I dont think so. The ABEC ratings arent important for this event. Our cars are not spinning fast enough or heavy enough for that to really play a roll (see what I did there, punny :P ). I think we've talked about this before on the thread
2011 Helicopters State Runner-up
2012 Helicopters State Champion
2013 Robot Arm State Champion

iwonder
Admin Emeritus
Admin Emeritus
Posts: 1112
Joined: May 10th, 2011, 8:25 pm
Division: Grad
State: TX
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by iwonder » March 20th, 2013, 8:13 am

The ABEC ratings yeild smoother bearings in my experience, which is why I looked for it when getting bearings. My back axle has a little over a kg on it and spins around 750rpm after the ramp, while my front axle spins a tad over 1000 rpm and has around 1/3 a kg on it. Plus the shock on the axles with a sudden stop, which I didn't want to mess up the bearings. Not to mention these were the only bearing I could find with an extended inner race :D
'If you're the smartest person in the room, you're in the wrong room' - Unknown

joeyjoejoe
Member
Member
Posts: 142
Joined: December 27th, 2012, 12:56 pm
Division: C
State: GA
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by joeyjoejoe » March 20th, 2013, 8:35 am

iwonder, I'm not sure I understand your reasoning behind the need for an extended inner race "so shaft collars don't cause more drag". I assume you are referring to friction between the inner part of the bearing and whatever you are using on your axle (plastic flange etcetera) to secure your wheel. Why would more surface area help in this regard?

Edit: Also, is there any benefit to having a larger or smaller outer bearing diameter? For example, if I have a choice between two bearings with identical specs except one has an outer diameter of, say 7/8" and another has a smaller outer diameter of 11/16, would one offer any benefits over the other (lower friction etc)?

Balsa Man
Coach
Coach
Posts: 1318
Joined: November 13th, 2008, 3:01 am
Division: C
State: CO
Location: Fort Collins, CO
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by Balsa Man » March 20th, 2013, 9:18 am

In general, if comparable quality, smaller will heve lower friction losses
Len Joeris
Fort Collins, CO

Mgras46
Member
Member
Posts: 3
Joined: March 20th, 2013, 9:21 am
Division: C
State: IL
Has thanked: 0
Been thanked: 0

Re: Gravity Vehicle C

Post by Mgras46 » March 20th, 2013, 9:25 am

What were some of the best scores in your division?

Locked

Return to “2013 Build Events”

Who is online

Users browsing this forum: No registered users and 1 guest