So I am asking all of the teams that bought ample extra banebot gearboxes, now that you have your designs and manipulators finished I’m hoping you have a few extra lying around the shop.
Because of the shortage our team ended up dissembling 2 cordless screwdrivers(Seen here)](http://www.amazon.com/Milwaukee-6539-6-2-4-Volt-Cordless-Screwdriver/dp/B00004T9QZ) and inserting our 395’s to power the top and bottom belts of our roller claw. It worked amazing in the shop through the hours of testing and thats the way we bagged it.
Fast forward to NYC and after our first match we discover the gearboxes gave out and some of the gears stripped inside. We spent the rest of the competition trying to fix them or find replacements; we never did. We had a backup screwdriver gearbox but the same thing happened to that one after a few minutes. Our bot never ran fully functional.
Now with SBPLI Regional in just 7 days there is no way an order from banebots will come in time. We never expected it to be a problem and now we’re in an epic dilemma. Find replacement gearboxes or come up with a completely new manipulator before LI.
We have searched and searched and called and called but there are no gearboxes out there that will come in time, so now we turn to the CD community.
We are in need of two (2) P60 3nn Gearboxes for our RS-395 motors. 81:1, 104:1, or 132:1 (both the same gearing but can be any of the 3 options).
We are prepared to pay $75 a gearbox plus pay for expedited shipping to get it here before our regional.
This is our last option before having to ditch a design that works so well if it only had the proper parts to run it.
Thank you to any team that helps, it will be an extremely gracious gesture and any success throughout our season would be in debt to you.
I would try and rework the drill gearboxes. Do you have the output shafts supported in external bearings? Drill transmissions will not tolerate any kind of side load and will absolutely eat themselves from the inside out if you have the output shaft unsupported. You can only expect a drill gearbox to provide rotational torque. Side to side loading such as driving a belt or chain or roller with it without additional bearings is out of the question.
If however you are experiencing issues due to excessive torque then you could try using the slip clutch most drills have to limit the torque going through the gearbox.
I wish I had a box of BaneBot motors to give away but we are still waiting for some spares to come in for ourselves.
Our team bought two 81:1 banebot gearboxes for RS-395 that we ultimately didn’t use. I will have to double check that they aren’t RS-550 (I ordered a few different options early since I was afraid of a lag issue). I went to your team’s website and emailed you through the “contact us” link, so feel free to get in touch with me if you still think you can use these parts.
Any appropriate gearing could still work. Banebots has still been reasonably prompt sending out part orders. While you’re waiting to hear from other teams, i’d order a pair of the RS-395 mounting blocks and a pair of 4:1 and 5:1 pinions from banebots. You’re likely to get those parts in time, and you can use them to make any P60 gearbox work for you.
Related question:
We were briefly looking at doing the same thing with either a cheap harbor freight screwdriver or a craftsman drill. The former had an all plastic geartrain, the latter had a metal final stage. So inquiring minds want to know: was your milwaukee gearbox all plastic or not?
You can email me at dniemitalo (at) linnmar.k12.ia.us - I see from thebluealliance.com that you compete this weekend, so let me know right away if you want me to overnight them. For now you can just have them, and maybe we can complete a trade in the offseason or something.
Kevin,
The milwaukee gearbox had the last stage metal and the rest plastic, the new black and deckers we used have one plastic and the rest metal so hopefully it holds up better.
We believe the cantilevered shafts, as you pointed out, were the cause of the failure, we have replaced the gearboxes with new black and decker drill gearboxes and removed the chain system. Essentially the gearboxes are now direct driving the roller shafts (hopefully) curing our problem for good.
Thank you for all of the suggestions and ideas and a huge thank you to Nemo, who went out of his way to get in touch with our team in multiple ways to try to ensure we get them in time for our competition. We knew it wasn’t a matter of if the CD community would help, only if it would be in time. Sure enough it would have but we explored other options and figured it out with new mockup gearboxes.
Thanks to all, especially Nemo and Team 967 for their gracious offer.
I was going to add that when we ordered some spare BB pinions and steek ring gears they shipped the same day and arrived in New Lowell Ontario in 5 days. I don’t know if they can overnight parts but you’d have to call them before ordering.
Good to hear you found a stronger solution. Regardless though, make sure the loads are isolated/supported. Otherwise your loads are bearing on a thrustbearing/bushing and the geartrain itself.