Problem with CIM-VersaPlanetary Setup (Choo-Choo motor)

[geomapguy]

Originally Posted by Ether

What does VexPro recommend for a 300:1 setup?

http://content.vexrobotics.com/vexpr...s_20140211.pdf

[Ether]

Originally Posted by geomapguy

http://content.vexrobotics.com/vexpr...s_20140211.pdf

Thanks Graham.

Roy, you said "They are bound to break". Have you guys broken one yet with this setup?

[AM694]

So a couple days back, I tried to put a hole in the CIM shaft corresponding to the position of the set screw hole on the Versa collar. This didn't work at all! Because I was using the Versa as a sort of guide for the hole I was drilling in the CIM shaft (and I did center punch it), I couldn't see that it was far too close to the edge of the shaft. By the way, the reason I was doing this was to put a roll or spring pin in through the Versa hole and the hole in the CIM shaft.

This resulted in a chipped 5/32" black oxide drill bit, a CIM shaft with a diagonal hole in it (luckily I was using an old one to test with), and all-around poor results.

Today I tried putting a tapped 6-32 set screw hole right on top of the Versa's keyway. This endeavor was more successful. The reasoning behind this try was that if we compress the key between the keyways of the CIM and Versa, it is less likely to slip.

Did anyone come up with anything similar? Did it work? Thanks a lot guys!

[Ether]

Originally Posted by AM694

This resulted in a ... diagonal hole

What is a diagonal hole?

[Answer42]

Originally Posted by jblay

We want to get the power that a CIM provides us, the other motors won't do the job at the speeds .

Actually two 775's would do the job. According JVN design calculator, your current setup has a stall torque of 80 foot pounds and a free speed of a little under two revolutions per second. Two 775's plugged into the dual motor input that vex pro sells+ plus swapping out the 5:1 stage you currently have for a 10:1 stage, gives you a gearbox with a free speed of a little over 2 revolutions per second, and a stall torque of 104 foot pounds. Provided you are using a half inch hex output shaft and not cantilevering the load too much, I would imagine that you'd still be safe. Especially providing that the key, and not the gearbox was failing in your current setup. But as you said you're running more torque than vex recommends already.

[AM694]

Yeah that was a bad description. It was just a really badly drilled hole...like the bit was walking even as it drilled or more likely was being forced to the side by something, though I can't imagin what.