Awesome, looks good! and a very similar manufacture method to what I would use... and i wouldn't mind wide wheels as wide as the, but I find the blue wheels have brilliant grip when treated and used well.
I have spent the past 2 days slowly putting this thing back together, analysing it as I go, and had it 95% ready and decided to drive it around a bit. Can't get enough practice and that.
I broke it. D:
Well, the rear right gearbox failed. Completely locked up. Managed to catch it before the motor burned out, so no issue there. The Gimson stuff also appears to be unharmed. It's our old friend the second stage pin that decided to come loose.
I'm a bit disheartened as I had finally got everything bolted back on, and minutes later I had to rip it all apart again, but having opened up the gearbox things could be a lot worse. Only a single pin failed, in the past all of them would fail in unison. And, the gearbox that went is the oldest we own, it's one of the two that Sam gave is at the '12 champs as a sorry for killing our robot (lol). It used to be in NST. I don't even know how long ago NST ran drills, but we have had it for a year (and used it overvolted, a lot) on top of that.
So, as just one pin gave way and it's an ancient gearbox I think we're still safe. It might well have been loose from the start. I have a replacement gearbox to put in. Don't know what we'll do if they continue to break...
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In other news we have made our battery box and have discovered we need an extra tensioner for the chain, which will have to be simple (leave in 3 days). In happy news, the wheels seem to be holding up very nicely.
how many spacers have you got in that gear box? as you've charged the reduction you would need 2 of the metal ones rather than one. as originally they had 2 spacers when they had the plastic first stage reduction, and then if you changed it to metal gears, you probably had to remove them. But when you changed it to 24:1 reduction, the gears are thinner so you need more spacers. The spacers should give the pins less room to fall out.
You don't need spacers in drill gearboxes, unless I'm not understanding something. If you mean the spacers thing mentioned on the Gimson website, that's unique to GR02s. In fact, you can't have them in drills, as it would force the shaft beyond the circlip and cause the whole system to fail.
Originally Posted by Ellis
What about the metal disks that are between the motor and first set of gears? mine came with two, and as you gearboxes looked identical, I presumed they were the same. I found that the pins came out if I was missing some. I don't know it yours are different though.
Ours have never come with two plates... that's odd. We once put two in accidentally (don't ask) and it didn't like it at all, but I'll look into that tomorrow. Thanks.
I think it's simply the mechanical limit of a pin pushed into a hole, then loads of lateral force being put on it. If over the past 3 years it has been used and used and used, every time the drill changes direction hard the pins come under stress. So if we're lucky this is simply fatigue and we won't see a repeat with the newer gearboxes.
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Also, oddly, one of the pinions on the 18v motors has come loose. Ewan has very kindly sent out a replacement, and we'll try to get the current one back together. I don't really have an explanation as to why it came loose, Ewan said he has never had a report of one loosening before, so I can only assume it was a dodgy one from purchase. Bit of a shame, as if we can't fix it we can't have any more test drives until we get to the UK and put in the new one, but it could be worse.
Stock up on GR02 drill shafts and replace them instead of the gearboxes.
If you take the shaft circlip off and remove the ball bearings, you can stick a screwdriver in the end of the shaft (careful not to damage the reverse thread) and hammer it out through the gearbox housing with relative ease. Hammer a new one in its place, then refit the bearings and circlip.
Done this many times over the years and not had a problem. A much easier solution now that Ewan stocks the shafts. Managed to 'make' six 12V drill motors the other week from old empty gearboxes just by stocking up on the shafts and motors
This sounds like a problem that could be fixed with a tig welder... You got 4 sets of plates with pins that have fallen apart? If so bring them along to the champs, I'm sure if you ask grant nicely he'll weld them up on one of the nights.
Feels like we've got more than 4 sets! I'll bring them along. Might as well weld any good ones too, and just avoid the issue.
Also Jamie, I've replaced shafts in these a few times, I just avoid doing it if possible as it feels quite invasive, especially if I have an alternate complete gearbox available. For the future we're going to try and ditch the reverse thread screw locking method and go for some form of grubscrew setup, the GR02 shafts will be perfect for that, with their flats. Had already crossed my mind to do that ahead of the champs but I don't see why the pins on those shafts would be any stronger, I believe they're identical. One day we'll run out of old drill shafts, I'll go Gimson shafts then!
Crossing my fingers that the failure we had was because it was an abused gearbox, and not because we're still putting too much stress on the pins. Don't see how we can be, to be honest, we're no longer overvolting...
Reading this thread is not giving me any confidence in my Argos 12v drills....
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