I’m looking for suggestions on the best way to cut the shaft of a CIM down. Is a band saw the best way? Or is there another option that would be better? Thanks! 
It can depend on what application you need to cut down the shaft for, but for most that we have had a bandsaw (and maybe some fine tune filing and grinding) works.
A hacksaw can get the job done easily with minimal risk to the motor itself.
Dremel cutoff wheel works fine, and moves fast enough that the axle won’t try to spin away from you like it can with a hacksaw.
A word of advice: unless you really need to cut the shafts (they interfere with something), don’t. We did this every year for our mecanum drive, we have at least 20 CIMs, but we couldn’t reuse the cut ones for the new EVO shifters, so we had to buy new ones. It is a big waste because the ones we have are perfectly good except for the cut shaft. So if you don’t absolutely need them cut, leave them as is.
Just my 2 cents ::ouch::
We’ve always just hack-sawed them. We’ve used pool noodles to hold them in the vise without marking them up. Also vise grips on the end of the shaft help to stop rotation.
I quite enjoyed running the CIM at full speed with a hacksaw up against it, but something tells me you are looking for a slightly safer option.
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Same here.
I usually clamp the motor down, power it, and hold a hacksaw to it.
Sort of a lathe in reverse.
But then I’m a control system guy…
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You get 4 CIMs a year with your KOP
[citation needed]](https://firstfrc.blob.core.windows.net/frc2017/Checklists/2017KOPChecklist-GrayTote.pdf)
Can’t say that’s ever been the case.
This is actually reasonably safe if you take precautions to hold the motor in a stable position. I’ll add that some shaft collars either side of the cut location help to ensure it is cut straight.
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There were 4 CIMs in this year’s KOP, they’re just listed in pairs in 2 separate sections (Page 9 and 14). That being said, I might echo the caution against making a habit out of cutting the shafts unless you need to. If you do it regularly, you’re losing out on potential spares.
Looking at the list you sent, there are two CIMs in the VEXpro Motor box and two CIMs loose, for a total of four. We definitely got 4 CIMs in the KOP this year.
Is this an alternative fact that I’ve been hearing about? 
I’ve done this a number of times and it’s worked every time. It is effectively the same as spinning the CIM shaft on a lathe and cutting it with a parting tool. The trick to staying safe is stopping when there is a small bit of the shaft left and finishing the cut with the motor off. then file (or bench grind) to finish. If done correctly and everyone is wearing the proper protective equipment, I don’t see why this method should be a problem.
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Is this to use use a CIM motor with a versa-planetary?
If I can find the 2014 kit checklist, I am pretty sure I can confirm that we have been getting 4 CIMs in the veteran kit since then. That’s also evident in what you linked. I don’t know if you didn’t read the link or if you’re playing 3D Chess while I’m playing checkers and this website is now operating on a level of sarcasm and irony beyond even my own grasp.
You could clamp it down in a horizontal bandsaw. Bonus: Hook up a multimeter to see your CIM’s effectiveness as a dynamo!
The way we have done it in the past is with a hacksaw. When doing it for a for a versa planetary where you also need the little nub of a key I put the key in the motor clamp it in with a pair of vice grips and then cut. Start with the key side and when you are done you have a key that is flush with the end of the shaft and you don’t have to worry about burs in the groove or on the key making it difficult to insert.
If you want it to be nice and you have a large enough lathe you could throw the lathe into a lower gear and then unplug power from and hit the estop on the machine just for satey. They you could put your company in the Chuck and power it on and use the lathe tools to cut the shaft. My only fear would be overloading the cim by taking too heavy of a cut. This would allow you to face the shaft and make it nice though which may be an advantage for getting stuff onto the shaft, not having to deal with burrs or weird filling jobs is nice.