We recently purchased a double set of vex pro mecanum wheels ( http://www.vexrobotics.com/mecanum-wheels.html ) with http://www.vexrobotics.com/217-3255.html , and we have no idea how we can mount them onto a tetrix bot… Anyone have any experience with these wheels?
Got access to a 3d printer?
My team has a 3D printer and we could ship a few of them to you. DM Me if you are interested.
The problem is that there are 2 different 4’’ mecanum wheels that vex sells. (http://www.vexrobotics.com/276-1447.html and http://www.vexrobotics.com/mecanum-wheels.html, we own the latter). This means that there is a chance that these models will not work with our wheels, and none of the descriptions specify.
This part is what you need. All the larger wheels made by AndyMark and vex both use a 1.875 bolt hole circle for attaching sprockets and gears. The plate I linked to has the right hole pattern to bolt to your vex wheels and the center is setup for one of the standard tetrix hubs. You could easily make this part if purchasing is not an option.
This won’t work for the 4" Vexpro mecanum wheels, they are the odd ones out since they’re so tiny. The drawing shows their bolt circle to be 1.125". http://content.vexrobotics.com/vexpro/pdf/217-3644-Drawing-20140926.PDF
You could drill a set of holes in the AM adapter plate that match the Vexpro wheel bolt circle, but getting them concentric with the axle would be a little bit tricky.
Maybe I could design an adapter to the vex axle that acts as an axle hub by forming the shape of a tetrix axle (round but flat on top) , that way the wheel would turn with the axle…no need to mod the wheel or screw anything into it
For future reference, these are cheaper and mount directly to the tetrix hub.
we have heard of many issues with these wheels, which is why we chose not to use them. Also they only support 17 lbs, which might not be enough for our bot.
The shaft on a Tetrix or Andymark NeverRest motor is 6mm. So need to get from 6mm to 1/2" hex for the Mecanum wheels you mentioned. Since the wheels are so wide (2.25"), I would recommend the really cool ThunderHex shafts from Vex Robotics. You could cut to the desired length, enlarge one end with a 6mm drill bit to fit on the motor, then drill/tap two holes for set screw. The wheels can be held on the shaft with Vex Robotics 1/2 hex clamping collars.
We built some shafts and drill/tapped with 8/32 and used the HeliCoil inserts to make sure they were strong. Never had a problem all season! Here is a link to the HeliCoil inserts we purchased on Amazon.
17 pounds per wheel not total.
Might these work?
In my option, they would be a little short for the 2.5" width of the Mecanum wheels.
The “3 wide” ones would work better.
These are only about 1.5" wide, so will not go all the way through the 2.5" wide Mecanum wheel. Could test and see if would work.
hmm… perhaps… a bit pricey. $28 with shipping for 4 of them… May be my only option, though. Surely other teams have used these wheels though.
Send me a PM with your address and I will send you a working sample of the ThunderHex.
Sent… wow thanks!