Attaching a wheel to an axle
 

We use the Small Part hubs for our driving our robot, but we have a ball roller with 3 six inch wheels attached to an axle. (The ball roller is on the front and throws the soccer balls up in the air.)

For the ball roller, we wanted the six inch wheels to be directly attached to the axle rather than free wheeling. To accomplish that, we went to a local hardware (forget Home Depot - they don 't carry this stuff around here) and bought brass bushings (1/2 inch inside diameter and 3/4 inch outside diameter -1/8 wall-plus another bushing 3/4 inch inside diameter and 9/8's outside diameter- 1/16 inch wall.) You need 2 sets for each wheel. There was a big differences in price at different hardware stores. The bushing are 3/4 inches long and have a flange - ie a metal rim.) We then popped the bearing from the skyway wheels and inserted the axle and bushing.

We recently built another balll roller during our 4 allowed days and this time we used 1/8 inch cotter pins going through holes drilled by hand on an angle, plus some other pins (3/16 and 1/8th). Previously we used a drill press with a long 1/8 inch bit to make holes for pins.

Our ball roller is up in the air and all it has to do is grab soccer balls so there isn't that much stress on it.

Attaching a wheel to an axle - correction
 

I am suffering from the flu and got my fractions messed up. My last post should have said:

(1/2 inch inside diameter and 3/4 inch outside diameter -1/8 wall-plus another bushing 3/4 inch inside diameter and 7/8's outside diameter- 1/16 inch wall.)

What we do is make the shaft bigger, but where the wheel is gonna sit, we make a step for the bearing to stop, the we drill and tap the end of the shaft and basically clamp the bearings. If your going to Nationals just look at what we do. Team 157.

"trantorque"

instead of using this try to make the shaft square. all our drive train shafts are square. we can change the sprokets very quickly by doing this. we Bought a square ID from small parts and weld it to all the spockets.

We put a lot of torque on our drive train and never broke loose.

this is a very quick and easy way to attach wheels our anything to your motors

Square drive shafts
 

Wow! That is a very interesting idea.

Do you pin your sprockets to prevent lateral movement along the shaft?

No. you let the sprocket free move. this will line the gears up nice. the chain keeps the sprokets from moving from side to side.

look at this

http://www.valleytech.k12.ma.us/robo...2%20Gears1.jpg


http://www.valleytech.k12.ma.us/robo...02%20Gears.jpg

thanks
 

Thank You so much for your help! Your my Hero!:yikes: