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seanet1310
Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide
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quote:
Originally posted by Nick:
At today's exchange rate a pair of Grimsons will cost at least $157 to import, while a pair of P60 gearboxes will be about $143. That doesn't include the crappy currency conversion from most banks or the VAT refund.
How so? Using checkout and google as a currency converter for both (so like you not including crappy currency conversions from banks or VAT) you get $131 for Grimsons. No tracking of shipment. Two P60 gear boxes, without motors cheapest ones I could see, no motors. $156 converted.
Both with delivery to Australia.
The Grimsons come with a small bearing kit useful in some situations.
Both offer spare parts for sale.
Not saying it is better but it seams to be cheaper. A lot of people have complained about Banebots in the past so despite the fact I have never used banebots, I would probably go Grimsons as a trial. Everyone has their own opinions and will make their own decision.
You do not get the ratio choice (but that puts the banebots price up somewhat as you get higher). Larger carrier pins, now this may be a problem, we will see.
More output shaft options, I was looking at more a drill replacement and the Grimsons do almost drop in, there are two output shaft options so it is still more then a drill and you can buy the mounting hub to give more options (http://www.gimsonrobotics.co.uk/12mm-GR02-shaft-mounting-hub.html)
Stronger Aluminium, may be important but, again time will tell but both will be stronger then drills and plastic mounts.
Grimsons will not be our source of cheap replacement 550's. with shipping pre vat and crap bank conversions looking at around $30/motor.
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Remember to trust me, I am an Engineer.
http://www.youtube.com/watch?v=rp8hvyjZWHs
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Mon Aug 05, 2013 8:50 am |
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Ellis
Joined: 21 Jul 2012
Posts: 129
Location: Shopshire, England
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Hi guys, UK builder here, name's Ellis.
Long post below, sorries.
We're in the same position drive-motors wise over here. In our robot Tormenta 2, we have been plagued by drill problems. The issues have always been gearbox based. The usual second stage pins come loose, second stage gears lose alignment, they get eaten, gearbox locks up, motor stalls and burns out in a puff of death-smoke malarkey. The motors have been bulletproof from the beginning, even when running 12v models on 18-20v.
We have had at least one gearbox give up in pretty much every fight since T2s first outing. I guess you could say we've had to make them work for us.
Changing out the plastic gears is a given. They're going to fail, unless the robot they're in is driven very kindly.
Once the plastic gears are out, every single failure we've had has been because of the second stage pins coming loose. There are other little ways these gearbox/motor combos give up but the main issue is with the pins on the output shaft. You've probably all had the same headaches we've had.
We were presented a solution which few seem to have picked up, by the guys running RoboChallenge. In short(ish), hammer out the existing pins on the OP shaft - the shaft must be fresh or the holes the pins go into will be mashed. They suggested 3.2mm silver steel for the next bit (good luck with sourcing that!), but I would like to try using old dead 550 motor shafts, as they should be the perfect size. Also it feels like something useful can be made from the buckets of dead drill parts. :3
The idea is cut 3 lengths of whatever rod you use, obviously must be a hammer-fit diametre, to a mm longer than the originals. Poke the extra mm through the hole, so that the extra is on the shaft side of the dealio. Then ball peen/round off/mushroom the extra rod until it's flat as can be onto the face of the plate (shaft-side). Point being it is wedged in there, and can't come loose. I think some decent metal glue wouldn't be a bad idea to throw in before hammering.
Very simple in principle, but we tried some shafts with this done to them and we did 7 fights without a single failure. That's a record, by about 6 fights! Have yet to attempt doing it ourselves with our limited toolset, but it makes drills usable so we're definitely gonna try.
I'd also one day like to try tapping the holes to m4, then sticking a bolt/grub in, and rounding the exposed bit to 3ish mm in dia. Assuming the crappy bolt material doesn't fail, it should work too, right? Maybe...
I will be putting a video up on YouTube (TeamExpat), in which I hope to address all of the failures we've seen and how to deal with them. I don't doubt drills have dropped in quality, but for a while longer at least, I think they're salvageable, and probably still a good deal cheaper than the alternatives.
tdlr; ways to deal with drill problems exist, or so it seems, I'll try to present what we've learned in video form, if it helps anyone, wahey.
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Mon Aug 05, 2013 8:52 pm |
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RoboWars Australia Forum Index
-> Technical Chat
Are you guys overtightening the grubscrews, maybe? Either way giving the botbitz 36 motors a go for nationals.