I’m curious what other teams use as COTS gear boxes for their FP motors?
Andymark has one planetary (that apparently requires a pinion swap) that doesn’t have that much of a reduction, as well as their GEM planetaries (which you could stack ~4 deep to get a 181:1 reduction.)
We’re looking at possibly using the FP to run a screw drive arm lift, but don’t have a lot of experience playing around inside a planetary gearbox, so we’re looking for (hopefully) a COTS solution.
We’ve used the Banebots P60 line of gearboxes with the FP before with lots of success. They take a little modification of the pinion (nothing that is against the FIRST rules) which is talked about in this thread.
In my experience the FP motor and many 12v 3/8" drill motors are interchangeable. You could buy a 3/8" cordless drill and swap the motor out, though you do this at your own risk as the motor might not fit.
Feeding an FP into an AM Planetary gives you a lot of options - Andymark’s entire line of gearboxes accepts the CIM input. This includes the GEM series and Toughboxes.
If you’re looking for a rather daunting reduction needed to slow down an FP enough to use in a simple arm (2700+:1) I’d look into the BB Planetaries.
(I was wondering if any of these didn’t involve a pinion swap, because we do not have an arbor press in our shop, but I’ll bet we could find someone to do it for us if it came to that.)
With enough creativity, patience and a bench vise, you can press a pinion on the FP shaft without a problem. As for getting the pinion off, there are many different ways that don’t involve a press.
You don’t need an arbor press. A hammer, punch, and bench vise will suffice to remove the pinion, and a nice bench vise or machinists vice is plenty to press the new pinion on.
We’ve made a pinion remover from a bicycle chain-breaker and box tube. We’ve pressed it on with a machinist’s vice. (However, you probably shouldn’t put an inexperienced student on pressing the pinion on; you don’t want to bend the shaft.)
And I’m trying to remember what gear ratio it is for (the 5:1 stage would be my guess), but one of the pinions is quite small, leaving very little material at the root. This can cause the pinion to crack when you are pushing it on. I’ve never had it fail in service… but for the cost of adding a few extra pinion gears to your order is less than the cost of having them rushed to you after you snap the one that you ordered!
Sometimes I spin up the FP (with the air vents taped off) and use a bit of emery cloth to take the pinion down just a thou or so in diameter. The pinion gears still hold, but are less likely to crack as you push them on.
Looks good! We did something similar in 2002 for our home zone tether, except it was kind of a rush job and didn’t look as nice as yours.
We’ve also ran the FP gearbox a few times with the final stage cut off and the output shaft attached to the second-to-last gear. We’ve found this is a nice quick speed that is suitable for a lot of things and it also makes the huge black (or tan) box a lot smaller.
