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Thread: Team Aggregat's Build Diaries

  1. #1
    Hi all,

    It's been a little over 10 years since I last built a featherweight (and that wasn't really up to much, I only went to one event with it), so I thought I'd start a build diary for my new featherweight. It's a scaled up version of my antweight, 'The Mole'. Working name is EnorMole.... But any suggestions for large mole related names are welome. :P This is the original Mole:



    I'm planning on keeping it fairly simple and am hoping to get it ready for Newport on July 20/21. The chassis is a mixture of 12mm and 10mm HDPE, with 4 drill motors. I'm currently testing on a 3s lipo, but will be using a 5s for the first event. Speedos are a bit ancient, they're some old 30A electronizes with the external relay mod that I pulled out of the shed, although it's only a matter of time before I get some Botbitz 85As.

    Anyway, first step was to get the drills and strip the motors out of them and grub screw down the clutch. For the wheels I've gone for some 1/8 buggy wheels. I fancied something different from the blue wheels or banebots wheels, and also I needed something that looked a bit like the wheels on the antweight version of The Mole. They don't seem particularly rugged or grippy, but they'll do for the meantime. They're attached to the motor shafts via 17mm hexes, which fit onto the motor shaft via a 17mm nut with a 3/8" UNF thread.





    Next up was some motor mounts made out of 12mm HDPE. Cutting the rear bracket was easy enough, but the front one was a bit of a pain. I'm pretty low tech when it comes to robot building equipment, but after lots of drilling, sawing and filling they all fit and are ready to be bolted onto the base plate. I'm sure there's probably an easier way to mount drill motors, but this seems like a pretty sturdy solution. The base plate is 40cm x 50cm of 10mm HDPE.







    The side panels have been cut from 12mm HDPE, as opposed to the 6mm HDPE I used in the antweight version. Next up was to cut some holes in the base plate for the wheels. They're not the tidiest edges as all I have is a jigsaw. Next up is to screw the motor mounts and side panels onto the base plate, then get the speedos all wired up.



    The main aim is to get something up and running for the event at Newport, so it will just be a basic 4wd pusher. But i reckon I'll have 4/5kg to play with, so I was toying with the idea of having interchangeable top panels with different weapons. I'm going for a simple axe first, then the plan is to make an interchangeable spinner module ready for the championships next year. At which point, I'm firmly expecting it to get destroyed, and then I'll start on a proper featherweight. I see this one as more of a learning experience.

    Sorry for the lengthy ramble, but I do really enjoy reading other people's build diaries, so fancied doing one of my own. I'll be posting further updates for my feather, and also info on my Antweights and the upcoming Beetleweight build (as soon as the parts arrive). Any advice or comments welcomed!

    Cheers,

    Rhys

  2. #2

  3. #3
    Looks very nice so far, better than anything I could do. As for motor mounts, what I believe is the easiest way, is to attach P clips to the front and rear of the motor, and use blocks of HDPE to raise it up. Cheap, effective, the only way I can (Bar Zipties). I haven't put them into practice as of yet, but I'd still have a look at it for future projects.

  4. #4
    Looking good so far, very nice

    The only thing I can offer as a suggestion for the front drill mounts is to simply cut a rectangle rather than the oval-ish shape that matches the drill gearbox case. I did what you've done in 20mm Nylon for the drill mounts in the first Drumroll and it took ages!

    If you go for the rectangle, just mark it out to 30mm x 25mm and cut it with a jigsaw. Easiest way to do that is to start off by drilling a hole in each corner of the rectangle big enough to fit your jigsaw blade through (I find 8mm works well) and then just cut from corner to corner. Means you can just cut in straight lines rather than having to worry about doing curves with it. Just make sure to cut on the inside of the lines you've marked, so that you're more likely to have a tight fit that you can rasp/file down rather than a loose fit that's difficult to 'undo'.

    And as someone who often makes long, rambling posts, I say the more the better
    Jamie McHarg
    RogueTwo Robots
    http://www.rogue-two-robots.vze.com

    With great power, comes great reliability.

  5. #5
    Looking good so far

    and theres nothing bad about electronize! They have served me well for 8 years and still both work haha, even if the robot does have the most inaccurate drive in the world..

  6. #6
    @Jamie, don't the gearboxes just spin in the mounts? I imagine cutting a square would allow too much play.

    The way I do it is I drill a hole that's the height of the gearbox (25mm?) and then with a curved edge rasp file out the sides, and with a flat one the top.

  7. #7
    Hey Mr Duff. Its Marco here from times long past! Hope you are well.
    Featherweight is looking great so far. 4 bar lifter would be cool and you should definetly have some weight to spare. I had electronize for a long while but one started to fail (possibly a sticky relay). I upgraded to a scorpion XXL which worked nicely with 4 drill motors.
    I have mounted drills like that in the past and it didnt work out too great. After a big flip I ocasionaly landed on one wheel and that often stripped a gear internally. If I were to use drills again I would brace the wheel on the other side. Bit of rod or a roller bearing.

    Aside from that, good luck! See you at newport

  8. #8
    Quote Originally Posted by PJ-27 View Post
    @Jamie, don't the gearboxes just spin in the mounts? I imagine cutting a square would allow too much play.
    Only if you cut it too big, and even then, the gearboxes will only rotate by a couple of degrees. Here's what you're effectively doing:

    drill.png

    So instead of cutting it to perfectly mate with the drill, the four corners (blue bits) are now just gaps. The properties of a rectanlge mean that it's not possible for any rotation to occur because the top and bottom are restrained in a gap of 25mm and the left and right sides are restrained in a 30mm gap
    Jamie McHarg
    RogueTwo Robots
    http://www.rogue-two-robots.vze.com

    With great power, comes great reliability.

  9. #9
    @Jamie, good point. Plus what with you drilling out the corners before cutting the straight lines you could add even more contact since the hole will have a radius.

  10. #10
    Cheers for the comments guys. I realised the rectangle thing just as I was filing down the motor mounts. But I guess its only a one off job, so I didn't mind spending some time getting it right.

    Marco, its been ages! I think you were at my last featherweight event all those years ago! I think the last time I saw you was at AWS 18 or something like that. So I take it you're coming to Newport too then? And as for the electronize, mine had a dodgy relay a few times, hence the external relay mod. The botbitz look in a different league though and are much cheaper. I think I'll wait for these to die first though.

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