How do you attach a wheel to a shaft?
Our dimensions for the wheels are: 6" diameter
Shaft is 1/2" diameter.
We need to know very quickly!!!
What’s the wheel for? Drivetrain or something else? Do you need it to handle a lot of torque and a lot of speed or no?
Depending on the wheel interior diameter- you would probably want to use a traintorque.
Heh - don’t hot glue a motor to a shaft and then the shaft directly to the wheel … a kid at our school (now a team member) found that it didn’t work too well for his electronics and robotics class… 
- Katie
I really hope you are kidding. That would be funny though
No, unfortunately I’m quite serious! One of our engineers picked up the wheel/shaft/motor and asked, “Who did this?” Then kind of sarcastically said, “Some kid not on the team?” and I said, “Well… no… he joined last week… he’s sitting over at that computer…” It was quite funny. I never got to see their machine run, heehee! I wonder if it ever did… :::shrugs::: 
- Katie
SilverStar,
I am assuming the whell is either for a drive wheel or a ball shooter wheel. In either case, a 1/2" trantorque may do the trick. Go to this website: www.fennerdrives.com
The Torque rating for 1/2" TranTorque is 350 in-lbs (~40 N-m)
The Chiaphua motor with an 18:1 gear ratio is about 40 N-m of output with no safety factor.
Hope this helps.
-Paul
This year our shafts are steel while our wheels are aluminum. To attach we welded a ‘yoke’ to the shaft then bolted the wheel to it this is the strongest method we have for dissimilar metals. Metal to metal we welded. I like trantorques also they work well as long as you have good tolerances. Also not sure how they work if the wheel was plastic probably not well. If you need more help post the materials of what you are connecting and someone can offer robust advice.
*Originally posted by Paul Copioli *
**SilverStar,I am assuming the whell is either for a drive wheel or a ball shooter wheel. In either case, a 1/2" trantorque may do the trick. Go to this website: www.fennerdrives.com
The Torque rating for 1/2" TranTorque is 350 in-lbs (~40 N-m)
The Chiaphua motor with an 18:1 gear ratio is about 40 N-m of output with no safety factor.
Hope this helps.
-Paul **
I’ll try that…
Doesn’t look like that’s going to work for us.
The bearings are still in the wheel.
We’re going to use clotting pins through the wheels and the rods.
Pins are bad, if there is alot of torque we have had some realllly bad problems with pins breaking in the past. would advise asgainst it.
Andrew
Okay, not using pins.
Still we need more suggestions, trantorque won’t work for us…
It is hard to recommend a solution when we can’t really see the problem.
Do you have a picture or can you scan in a sketch of your set up?
Joe J.
P.S. If you are using Skyway wheels, we have had good success chucking the wheels up on a lathe, boring out the center hold to a whole number (1 1/8 for example), then pressing in shaft and pinning the shaft to the wheel. The larger diameter hole makes pinning an easier thing to deal with.
Another method is to use the Small Parts Inc. adaptors.
Yet another method is to use bolts and spacers. If you have a sprocket that you can get the torque to, then go directly to the wheel spokes with the torque rather than going to the shaft and then from the shaft to the wheel. One way to do this is to put bolts into the sides of the sprocket. Use the spacers to key the bolts perpendicular to the sides of the sprockets. It can work well.
Finally, give us a sketch or a picture to work with and we will have better ideas to share.
*Originally posted by Andrew Rudolph *
**Pins are bad, if there is alot of torque we have had some realllly bad problems with pins breaking in the past. would advise asgainst it.
Andrew **
Pins aren’t always bad if you make sure they have a large enough radius to withhold the maximum applied load. However, if you use pins you should be careful… Depending on the setup, the material around the pin may actually be a lot more susceptible than the pin itself. Lots of time, the material around it will yield (deform to a great enough extent that when the load is released the material does not regain it’s original shape). As a result, lots of times the pins will fall out because the pin is no longer a press-fit and is loose. I’ve seen a number of cases in my years with first where pins fall out during matches or at the worst possible times. I’ve never seen a pin break although it certainly can happen.
There are also many ways to use pins. You can place them in a number of different geometries, each having certain advantages and disadvantages. I’ve done a bit of research into pins for a class I’m taking so if you would like I can post all the different types of pins you can use and how to make the associated stress calculations.
- Patrick
Hm, so is there some advantage to locking a wheel and sprocket to a shaft as opposed to locking a sprocket right onto the wheel (a la wheel hub)?
We’ve always used the SPI hub kits, and just let the wheel ride on it’s bearing on a shaft…
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.
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
*Originally posted by Mike Norton *
**“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 **
Wow! That is a very interesting idea.
Do you pin your sprockets to prevent lateral movement along the shaft?