As you can see it is nothing too complicated (still it requires some work if you don’t have any experience)
The motor used in this specific project is: Banebots FIRST CIM 12V 5280 RPM 345 oz-in Brushed DC Motor (it is reported in the comments of the video)
So I will buy it here on Robotshop robotshop.com/eu/en/banebots … motor.html
But there are some problems:
what wheels can I use for this project? Can you provide a link?
(I guess the diameter should be around 7 or 8 inches (= 18 or 20 cm) and the wheel should have a certain friction and shouldn’t be too thin)
how can I connect the wheel to the motor? How can I “extend” the 3.3 cm motor shaft? (look at the video… it’s around 15 cm or more)
I’ve found this 8 mm set screw hub robotshop.com/eu/en/set-screw-hub-8mm.html but I don’t know if using it actually makes sense.
Can anyone please point me in the right direction? Links to robotshop products would be very appreciated… Thank you
The diameter and RPM determine the tangential velocity (v = angular velocity x radius) at the point where the ball is launched
You’ll need a shaft coupler and an additional shaft.
The wheel and hub you choose should be from the same manufacturer and have the same mounting hole pattern. The center of the hub (“bore”) should match the shaft diameter.
CIM motor -> Shaft Coupler (8mm to ?mm) -> Shaft Extension (?mm)-> Hub -> Wheel
The opposite end of the shaft should be supported by a bearing.
Note that at the speeds you need, the wheel needs to really be fixed to the shaft; you should flatten part of the shaft where the set screw will sit.
That specific wheel has a 3/8" bore with a key; your shaft would need to be 3/8" diameter and have a keyway (not easy to machine)
Hello!! Thank you very much for the help. I understood what you explained (at least I think so XD )
I would like, as a first test, to avoid using a (shaft coupler + a second shaft + bearing) like in this video (52 sec video) youtube.com/watch?v=34PPXSilSdc.
Anyway, could you confirm that the 2 following solutions are valid?
The hub and the wheel are not from the same manufacturer but the specifics are matching.
I am interested in the first solution as it would be great for a quick test. What do you think? Can this setup damage the motor shaft? (…because the motor shaft will bear all the weight of the wheel. As you can see in the video, there is no support on the opposite side, so the wheel is sustained only by the shaft connection to the motor. Can this be a big problem?)
The CIM has an 8mm diameter shaft, and the Devantech hub is for 8mm shafts, so in theory they should work together.
It would be luck if the Anymark wheel fit the Nexus hub; altough they each have six equally spaced holes, the Nexus hub is designed for Nexus wheels.
We’d instead suggest the first option.
As you suggested “…CIM motor (8mm diameter shaft)-> Shaft Coupler (8mm to ?mm) -> Shaft Extension (?mm)-> Hub -> Wheel. The opposite end of the shaft should be supported by a bearing…”
Problem: I can’t find a shaft coupler that is 8mm at one end and “X” inches at the other one!!
This is the only one I found robotshop.com/eu/en/5mm-to-8 … upler.html
But I would like to have 8mm to 8mm OR 8mm to 3/8".
Can you link me these products if there are any?
Maybe I am wrong, but I would like to “get rid” of mm and pass to a shaft with a standard inches dimension because the majority of robotic parts (hubs, actobotics aluminum channels, bearings…etc) are in standard inches dimensions (that don’t have a precise correspondent mm standard dimension).
For example, the standard dimensions 8mm and 3/8"… the second corresponds to 9.5 mm??? And 1/4" = 6.3 mm. So… what about a correspondent measure for 8mm?
I know that in theory everything is possible, but I don’t have specific tools at home to produce custom parts so I need to stick to the basics.
Is (what I wrote above) right or wrong? Is there a quick solution for this problem?
P.s. Sorry, I know this is basic knowledge for you, but at first it’s a bit confusing. I hope you can help me make everything a bit more clear
Unfortunately none of our suppliers seem to have this product… but it likely does exist somewhere. just need to find it. Google is your best friend here.
3/8" corresponds to 9.525mm, which should fit 10mm with a little room to spare.
8mm corresponds to 0.3149 inches, or a hair over 5/16"
You can try an 8mm to 10mm adapter (if you find it) or a 3/8" to 5/16" adapter (again, if you can find it). You may need to enlarge the hole, or add a bit of tape or something else to fill a 0.5mm gap.
Does forcing the USA to use the metric system count as a “quick fix”?
Unfortunately this is something that people always need to deal with… certain parts may be in metric, while others are in imperial.
