Versa Planetary Configuration Tool

I wanted to share a tool I’ve been working on for the last couple days, one of the things I frequently see teams doing is designing beyond the specifications of the VP gearboxes without realizing it. But I’ve also had problems with "crap what parts exactly do I need for this configuration. So I built a tool to address both concerns.

Default - no stages or inputs/outputs selected

A sample good configuration

Exceeding the suggested max output.

It will currently do some sanity checks (do you have input/output and stages, check that you aren’t going beyond 4 stages, and checks the max torque of the output stage.

Im aiming to add more and polish the UI a little more over the next couple weeks (Those of you who saw old version on my twitter can already see improvements) as well as the double input options and VP Lite gears. I would LOVE to add per stage torque calculations but I don’t have max torque for each stage, if someone from Vex would like to provide those (@JVN hint hint) I would love to include them as well as add some additional design rules if people have any good ones.

I hope it’s something teams find useful and look forward to hearing any feedback (you can skip “it’s ugly”, I’m working on it)

Edit: And yes, @Billfred already gave me the “why no AM tool” spiel, I wanted to get this one polished, it’s built with swapping rules and parts in mind.


Looks very useful as a sanity check.

If you’re looking for features to add, I might recommend a warning if the user puts stages in the wrong order (i.e. anything other than motor -> highest -> lowest -> output). That should help prevent teams having their VPs fail even though they stayed within the recommended reductions.

@Andrew_Schreiber it looks like an excellent tool for teams to use to quickly write out a gearbox design. Any thought as to adding additional options for motor inputs, or are you just sticking with motors available directly from Vex in this version?

It’s on the todo list, adding motors isn’t a HUGE challenge. It’ll require a partial redo of the PN handling but that won’t be too bad. (Basically, I have to add a supplier to the part number field I’m using the join everything together, I’ve been bunting on it). Request noted and will def work on it.

So, that’s why I was asking about the per stage torque limits. I’ve heard anecdotally that the 5:1 stage is strongest but I don’t have numbers. I’d also like to know RPM limits for things like encoder stages since I’ve heard, again anecdotal, of people melting those stages at high RPMs.

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I know these aren’t probably the most important things and a good mental exercise, but maybe having the total reduction and torque type figures pop up as well, even for “properly-constructed” gearboxes could be helpful.

I really like the simplicity of the UI, just drag and drop, the total price is neat too, could even be used when calculating BOM costs.

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Your wish is my command, added Torque and Total Reduction displays.


Good Job! I think it will help teams doing this type of design for the first time, and hopefully look into “why” and further understanding if they do it incorrectly.

Nice but I did find a bug in that if you use the 5 to 1 icon it is calculated as a 4 to 1.

I agree that it would be nice to remind people to assemble them with the highest reduction nearest the motor and the smallest near the output.

Dang it. I coulda sworn I fixed that typo. I’ll update in a little bit. That’ll be fixed tonight and I’ll double check the part numbers.

Update - fixed it. In case anyone was curious, the stages are represented by a JSON structure that consists of some mechanical information and an array of part numbers. I obviously copy pasted a lot of these and modified, the 5:1 stage was copied off the 4:1. I changed the part numbers already but forgot to change the set up reduction. I’ve checked the rest of them and they SHOULD be good. Obviously, if you catch something lemme know and I’ll fix it asap.

Thanks for a very useful tool. Adding a VersaDM stage will make this even more useful!

awesome!.. could you add the hardware necessary… my kids always need to find the right length/size bolts for the # of stages, and then the right size/length for motor plate mounting (to the gearbox and to the motor itself). I know its in the manual…

I’ve had kids force 10-32’s into the motor mounting holes which take 8-32’s, because they overlook that there is a difference :man_facepalming:

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Seconding adding VersaDM/Bevel/180 would be great. Really nice work Andrew, it’s a cool thing to see out there!

I’d like to know these limits too. I’ve run some gear formulas for Versaplanetary stages, and they predict much lower torque limits than Vex’s load guide suggests. I’d love to see the design numbers.

I didn’t see any published numbers for those either. That’s one of the reasons I held off on adding them and the encoder stage. I’m hesitant to add in things without published or tested numbers to prevent false confidence that things are safe.

That’s a fair reason. Putting it like that highlights the risk that using some of those “nice” tools potentially poses to teams pushing the limits.

Truth. I’m less concerned if someone like 254 or 148 uses it and it gives them not wrong but not right results due to an odd config. They will iterate right past it, likely check the math and tell me it’s wrong.

But if I give Team 7xxx bad info they likely assume it’s them not the tool and get discouraged. As such I tried to use only published info and fairly conservative rules. I’m always nervous making tools easier to use because lowering the bar to use them means some of the users may not have the experience to know when the tool isn’t useful.


Looks Great.
Have you considered adding the encoder slice to the tool, not really for calculating load but more for finding the total price of each gearbox?

@Andrew_Schreiber Andy chance you could add the various gear ratios for the DM input? I think right now it assumes a 1:1 in the VersaDM module, but there are options for 3.75:1 and 5.33:1.

Yeah it assumes 1:1 I’ll swap that over tonight to support the two reduction options.

It’s something I considered, and I’ll probably add it in tonight when I push the VersaDM changes. I delayed because I don’t know if that stage adds any new limitations. Im going to assume no for now until someone tells me otherwise.

Just found this, and it’s great! Thanks so much for all your hard work.