Gravity Vehicle C

[iwonder]

Yeah, pillow blocks, the company I buy them from groups them under mounted bearings, so I just call anything like that(flange mount and others also) mounts bearings.

[illusionist]

Yeah, pillow blocks, the company I buy them from groups them under mounted bearings, so I just call anything like that(flange mount and others also) mounts bearings.

How much did they cost? The cheapest I've seen on Amazon was for $7.

[iwonder]

Oh... We get them for about $17 a piece... You have to realize that we put about $100 into our vehicle last year, $80 in bearings(impregnated bronze, big mistake) and wheels.

So this is just a dream at the moment, but has anyone ever seen/thought about using magnetic bearings in gravity vehicle? Ones of this size(1/8"-1/4") seem feasable with permanent magnets, I'm just wondering if they would be worth it...

http://www.pitsco.com/store/detail.aspx?ID=2604 <- from the mousetrap vehicle thread

[illusionist]

Oh... We get them for about $17 a piece... You have to realize that we put about $100 into our vehicle last year, $80 in bearings(impregnated bronze, big mistake) and wheels.

So this is just a dream at the moment, but has anyone ever seen/thought about using magnetic bearings in gravity vehicle? Ones of this size(1/8"-1/4") seem feasable with permanent magnets, I'm just wondering if they would be worth it...

http://www.pitsco.com/store/detail.aspx?ID=2604 <- from the mousetrap vehicle thread

Oh wow... Yeah, I'm looking for the cheapest option (which is always DIY).

I thought of GV too when i saw that on the Pitsco website, but dismissed the idea due to the stress the axles would experience as the vehicle transitions from vertical descent to horizontal motion. i thought that the axles might pop out of place due to the change in direction. I might be wrong, but I don't think it'd work too well.

[Balsa Man]

How do you mount the bearings to the chassis? My thought is to use a block that is mounted underneath the chassis, with a hole large enough for the OD of the bearing to fit in. With this method though, I'd imagine that the bearing would fall out of the block when braking occurs.

After looking through last year's thread, I found this response from Balsa Man about the topic:
"You set up bearing holders so that that the outside diameter of the bearings fits snugly into them, and the inside diameter of the bearings fits snugly on the axle. A way to do bearing carriers is use a piece of some kind of bar- aluminum, plexi, or lexan. For instance, we are using 1/8th axles, with ¼” o.d. bearings, 1/8th” wide. Bearing holders are ½” x 1/8th lexan bar, with slots filed in ¼” wide x ¼” deep. The tricky part with a live axle is getting/making sure the axle is straight; if its not, you will get wobble, which will cause vibration at speed, and movement of the bearings (or if the bearings are tightly held, binding)."

You say that the bearings are 1/8" wide, and that the bearing holder is 1/8", yet you drill a hole that is 1/4" deep in a 1/8" wide bar? I might be misunderstanding it. Can you please clarify?

Certainly.
Understand the confusion. Holders are 1/8th thick, by 1/2 wide. So, a quarter inch hole leaves an eighth on each side.

[illusionist]

How do you mount the bearings to the chassis? My thought is to use a block that is mounted underneath the chassis, with a hole large enough for the OD of the bearing to fit in. With this method though, I'd imagine that the bearing would fall out of the block when braking occurs.

After looking through last year's thread, I found this response from Balsa Man about the topic:
"You set up bearing holders so that that the outside diameter of the bearings fits snugly into them, and the inside diameter of the bearings fits snugly on the axle. A way to do bearing carriers is use a piece of some kind of bar- aluminum, plexi, or lexan. For instance, we are using 1/8th axles, with ¼” o.d. bearings, 1/8th” wide. Bearing holders are ½” x 1/8th lexan bar, with slots filed in ¼” wide x ¼” deep. The tricky part with a live axle is getting/making sure the axle is straight; if its not, you will get wobble, which will cause vibration at speed, and movement of the bearings (or if the bearings are tightly held, binding)."

You say that the bearings are 1/8" wide, and that the bearing holder is 1/8", yet you drill a hole that is 1/4" deep in a 1/8" wide bar? I might be misunderstanding it. Can you please clarify?

Certainly.
Understand the confusion. Holders are 1/8th thick, by 1/2 wide. So, a quarter inch hole leaves an eighth on each side.

Based on your description, I'm envisioning something like this: http://woodgears.ca/gear/bearing_mount2.jpg , where the wood piece is as thick as the bearing (the outside faces of the bearing are flush with the outside faces of the wood).

Now with a design like that, how do you prevent the bearing from slipping out of the holder? The image I've linked to above shows a a screw used to tighten the wood and grasp the bearing. Any other options? A couple self-threading set screws coming in from the top and bottom of the wooden holder might be able to be used.

[fishman100]

Now with a design like that, how do you prevent the bearing from slipping out of the holder? The image I've linked to above shows a a screw used to tighten the wood and grasp the bearing. Any other options? A couple self-threading set screws coming in from the top and bottom of the wooden holder might be able to be used.

Maybe a C-Ring would work..? If so then you'd have to have a thicker block of wood, but not by much. http://www.bmikarts.com/shop/images/Uni ... -20618.jpg
C-rings such as the one in the image above requires special pliers (snap ring or C-ring pliers, I think that's what they're called), but there might be a way to do it without one (I don't have any C-rings so I haven't tried it yet).

Last year I did something similar to the pic Illusionist's posted: take the bearing, put it in a block/housing, clamp it down with a screw, and place washers/nuts on both sides of the housing to prevent it from moving. It worked well, and it only came out once.

Also, how are people attaching their wheels to the axles? I've tried tightening nuts/locknuts/wingnuts on both sides of the wheel and tapping the wheel, but neither have produced desirable results.

[illusionist]

Now with a design like that, how do you prevent the bearing from slipping out of the holder? The image I've linked to above shows a a screw used to tighten the wood and grasp the bearing. Any other options? A couple self-threading set screws coming in from the top and bottom of the wooden holder might be able to be used.

Maybe a C-Ring would work..? If so then you'd have to have a thicker block of wood, but not by much. http://www.bmikarts.com/shop/images/Uni ... -20618.jpg
C-rings such as the one in the image above requires special pliers (snap ring or C-ring pliers, I think that's what they're called), but there might be a way to do it without one (I don't have any C-rings so I haven't tried it yet).

Last year I did something similar to the pic Illusionist's posted: take the bearing, put it in a block/housing, clamp it down with a screw, and place washers/nuts on both sides of the housing to prevent it from moving. It worked well, and it only came out once.

Also, how are people attaching their wheels to the axles? I've tried tightening nuts/locknuts/wingnuts on both sides of the wheel and tapping the wheel, but neither have produced desirable results.

Thanks for the suggestions. The washer idea seems like it'll work well.

I've always used two nuts on both sides, tightened in opposite directions. I add a little bit of hot glue so that it doesn't turn on the axle. Haven't ever had problems with that method. I'd love to hear what others do as well

[retired1]

I use a blind hole for the bearing and put a washer that matches the OD of the bearing in the hole first.This prevents any friction with the bearing walls. On the outside, For a 1/8 shaft, I use a piece of refrigerator water line. It perfectly matches the inner hub of the bearing. I have tubing that will fit most any diameter. Lots of hardware stores that sell it by the foot will give you 6 inches, free, for SO. In some cases I will use SS washers and teflon washers.
For the wheels, I just double nut them and firmly tighten them against each other. Two box end wrenches. No glue required.

If you use a wing nut brake, I take the "all thread" and "chase" the threads with a die. Smooths it up so there is far less friction. If no parent has a die, check with your school Mx. They might have one. Use oil or cutting fluid.

[_HenryHscioly_]

For my wheels, I use a lockwasher+nut on each side.

What does

"chase" the threads with a die

mean?

To prevent bearings from falling out, could you just put a little bit of glue?
I was contemplating on using cement glue, and then I could just use acetone to get them out if I needed to.