[PROJECT] Heavy Duty R/C Tool Box

Discussion in 'Other Toys/Hobbies' started by ShadowBurger, Jan 18, 2017.

  1. g@z

    g@z Member

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  2. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Thanks g@z. I am familiar with ackermann geometry but decided it wasn't a concern with this. The rear axle is solid (ie. no diff) so it'll struggle to turn with a heavy load on a grippy surface like concrete anyway. The steering as it is (just eyeballed to be approximately straight) works pretty well and apart from an overly wide turning circle I can't see any need for improvement. It's only built to carry some stuff through the bush so there's no real need for much precision

    To be honest I'm not sure I would have succeeded at getting the angles right anyway - as it stands one of the front wheels is a good 10mm higher than the other due to my shoddy engineering :rolleyes:
     
  3. dan441

    dan441 Member

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    Looks great! :thumbup:

    I may have missed something, but what functions as brakes for the vehicle when it's stopped or powered off when on a slope?
     
  4. OP
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    ShadowBurger

    ShadowBurger Member

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    cheers! The motor controller shorts the motor output when powered off so it does apply braking, but doesn't do much at low speed. So it could run away but only at a walking pace. Apart from that, whatever gets in the way will stop it eventually.... :thumbup:
     
  5. mtma

    mtma Member

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    The classic cheat with some early RC cars to get around this was to only have one driven wheel :lol:
     
  6. OP
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    ShadowBurger

    ShadowBurger Member

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    Finally happy with the frame, I've given it a lick of paint:

    [​IMG]

    I forgot about those top bars which obviously can't take any weight (they bent under my fat arse) so I added in some extra lengths of tube steel to hold it up:

    [​IMG]

    I've begun painting the parts of the frame which will be exposed in black. Parts hidden behind alu sheet I'll leave with a few coats of etch primer... I hate painting so less is more.

    I've started on cutting up the alu sheet between waiting for coats of paint to dry. It's surprisingly easy with a jigsaw :thumbup:
     
    Last edited: Mar 8, 2017
  7. OP
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    ShadowBurger

    ShadowBurger Member

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    Tonight I cut some alu for the lid and riveted the frame to it

    [​IMG]

    Lots of rivets, but using the gaps in the pattern meant I didn't have to do any measuring... all finished in a couple of minutes.

    [​IMG]

    Annoyingly the alu was left outside for a while and got a touch wet in one spot. I didn't realise when I cut it up that I happened to use that exact spot for the inside of the lid... :rolleyes:

    [​IMG]

    Wasn't happy with how it looked so I cut up some carpet and spray-adhered it to the inside of the lid.

    [​IMG]

    Lined up the hinge and riveted it in place. Surprisingly the lid went on very easily - payed off to take the time to measure everything three or four times at every stage when I was building the frame. The frame doesn't look like much but it's come out exactly how I wanted where it counts.

    [​IMG]

    Inserting all the rivets ready for popping. Skipped every other pair of holes as I don't have enough rivets but I'll come back and fill them in at a later point. It did come with counter-sunk screws but it would have been much more time consuming and I hate threading screws into thin metal, it always strips the thread. This will be much more permanent.

    [​IMG]

    Quite happy with the lid! I have to work out a way of holding it flat so it can be used as a table - I'm thinking some sort of collapsible legs would be best - better than a hinge stop of some kind - due to the high centre of gravity. Any real weight on the lid while it's open will tip the whole thing over and wouldn't be real stable

    [​IMG]

    Next up is to dress the edges with the angle aluminium. I'll glue that on with silicone so that'll hide the rivets and the edge of the sheeting.

    [​IMG]

    Stay tuned...
     
  8. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    I cut out the side panels and attached them today. Because I sandwiched some carpet between them and the frame, I wasn't able to get rivets in around the carpet, it was too thick. I resorted to the brassy coloured wood screws which worked quite well but look ugly. I'll see if I can find some plastic caps to dress them a little.

    The wheel arches were cut pretty easily with a jigsaw. I had to cut the blade short to clear the inner structure of the frame, since I cut the panels once fitted (easier than trying to clamp them down)

    [​IMG]

    This is the strip of carpet sandwiched under the side panels. Since it was only the top, I was able to rivet on the bottom half

    [​IMG]

    [​IMG]

    I put the two-piece floor back in

    [​IMG]

    You can see what I mean about the ugly screws. I hope plastic caps on them makes it look a bit better... maybe chrome ones will look good

    [​IMG]

    Next is the front and back, then all the electronics.
     
  9. g@z

    g@z Member

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    I need this for an Esky :)

    Regards,
    g@z.
     
  10. mtma

    mtma Member

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    Probably torx buttons or countersunk torx/inhex will look nicer.
     
  11. OP
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    ShadowBurger

    ShadowBurger Member

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    Thx mtma, they look the goods :thumbup:

    -

    I got sick of looking at the two-motor setup and the awful gearing I'd built (not proud). The chain kept coming off the really big sprocket and I wasn't having any luck with sorting it out - it was just a bad design. I want this thing to be reliable, not fragile, so to work out what I really needed, I built this tool to quickly get the data I needed while I searched through a range of options. I ended up ordering this new motor. It's rated to more than twice as much power as both the existing motors combined and its gearing enables me to use a much, much smaller sprocket on the axle (20 teeth as opposed to 80) while still getting higher torque and more (effective) speed.

    [​IMG]

    To give you an idea of the difference between old and new, the current dual motor setup with the big 80T sprocket achieves a final drive speed of approximately 14.8km/h. The new motor with a much smaller 20T sprocket achieves a final drive speed of 9.5km/h (these numbers based on 10" wheels). This is still quite a bit faster than walking pace and with more than double the available power it should manage that speed comfortably if I need it to. The previous setup was built just using parts I already had, so I'd never calculated the rated speed - if it had the torque, it would have run at 25km/h with the 47 tooth sprocket.... no wonder it could barely move its own weight.

    I'll have to build a new motor mounting again :tired: Should be worth it though, this new setup will use chain twice as big (12.7mm pitch instead of 6.35) and less parts so it should be a simpler process and way more reliable. The old adage of do it once / do it right etc... :rolleyes:

    Incoming Esky trailer for the R/C toolbox!
     
    Last edited: Nov 8, 2018
  12. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Quick update. Havent had a lot of time to work on the project lately. Im slightly stuck on needing to cut down the sprocket for the axle, which I didnt realise had a flywheel on the back of it...

    [​IMG]

    Trying to use the grinder to cut it off went well up until the last mm or so when I realised the cutting wheel isnt big enough... The hub of the grinder gets in the way. Ill have a look for a regular nut to use in its place, hopefully removing any need for me to find another way to cut it

    [​IMG]

    The new parts look the goods though. A side by side comparison of the old and the new shows the difference between them - the the teeth on the new sprockets are massive

    [​IMG]
     
  13. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Still on a really slow burn with this project. I've been stuck with the hole in the centre of the sprocket not being big enough for the axle and not having a drill bit large enough to widen it. 16mm is beyond the range of every set of drill bits I could find at local hardware stores, so i've been waiting for one ordered from eBay. I had a crack at widening the hole with a dremel but it was way too slow and I ended up with the hole off-centre... So I ordered a second sprocket.

    With the proper drill, the job was much easier although still very slow. I opted to drill before I cut the flywheel off this sprocket as it would result in a straighter hole. Lots of engine oil was squirted from a repurposed sauce bottle during the drilling to keep the bit cool and lubricated.

    [​IMG]

    Even taking it slow and steady the drill motor still got very hot. The drill gearbox was on its slowest speed but drilling holes this size is really hard work especially on a cordless drill. A drill press would have been ideal but I don't have one. You can see the size of the bit in the background

    [​IMG]

    The drill eventually cut through it still looking sharp at the end. Definitely would never have finished if I didn't keep the oil on it constantly. The hole is dead straight and the calipers see it as right on 16.0mm

    [​IMG]

    Like a glove! I found a new spot for the bigger motor as well, although I'll definitely be building some more supports for it - those two screws are hardly strong enough

    [​IMG]

    Unfortunately I'm stuck again. The sprocket on the motor is the correct pitch but is designed to suit a chain with smaller diameter rollers (didn't even know that was a thing). I'm between a rock and a hard place; I can either take to the motor sprocket with the grinder to narrow down the teeth so the 428 chain fits on, or start again with a different sprocket on the axle and some different chain... only it seems the size of chain the motor sprocket is designed for is unavailable anywhere practical.

    EDIT:

    Attacked the sprocket with the grinder and the chain fits it now... :)

    I tore down the motor to check out its internals and found it to be very nicely made inside. So much copper..

    [​IMG]

    I fashioned a mounting bracket from some spare steel. I'll add another piece perpendicular to this one to make use of the third bolt hole and add some rigidity

    [​IMG]

    A test fit was successful!

    [​IMG]

    Pretty big difference between the new chain and the old

    [​IMG]
     
    Last edited: Mar 31, 2017
  14. OP
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    ShadowBurger

    ShadowBurger Member

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    Guess I should post an update! Finally finished the bracket for the new motor. It got painted as well but I haven't got a piccy

    [​IMG]

    I've cut out the panels for the front and back bodywork but need to get a new rivet gun before I can attach them. Other projects have been taking up all my time... but here's a video of its first real, successful test drive! It drives perfectly! :D:D:D

     
  15. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    I finally put ends on the toolbox. I used angle aluminium which matches the 5-bar checkerplate on the sides to cap the ends where the plates join. I just used double-sided tape to mount it. There is headlights behind the front plate - I'll have to cut out holes for them I guess but I'm not totally sure if I want to keep them as they're purely aesthetic.

    [​IMG]

    I'm very pleased with how it looks!

    [​IMG]

    It performed very well on the weekend and I have already had a couple of requests to build some for other people. One of them has a disability and is permanently on crutches so this could actually be a very valuable tool for him. He has to carry just as much gear for the hobby as the rest of us and we struggle as it is...

    [​IMG]

    I tested its load bearing capabilities. Needless to say it barely notices the load of a human! :D Seriously this machine has oodles of torque... it goes up hills and through long grass with me sitting on it as though I'm not even there

    [​IMG]
     
  16. dan441

    dan441 Member

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    Very sweet! How much usage time have you been getting off a single charge with the new motor?
     
  17. OP
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    ShadowBurger

    ShadowBurger Member

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    Thanks! Running from a single 6S 8000mAh I reckon a good 15 minutes. That was broken up throughout the day with people riding on it, not just gear, so id have to do a proper test and find out. It's plenty though, enough for a good long drive and then some
     
    Last edited: Apr 24, 2017
  18. OP
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    ShadowBurger

    ShadowBurger Member

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    Here's a bit of follow up on this project which is (mostly) finally completed.

    I've made a couple of changes since the last update
    • added a length of chain to hold the lid when open
    • did the rest of the riveting on the continuous hinge
    • rebuilt the drawer from scratch - it fits much better now and the slides are smoooooth
    • removed all of the lead-acid charging batteries. I've been field charging using an 8ah 6S LiPo and also driving the Mule on another, so I took them out to save weight
    • the steering motor has a metal output shaft which is only glued into a plastic spurr gear with no keyway... It's a poor design so I drilled a hole and put a pin through to retain it. Not thrilled but it does the job... I'd have to spend more than $180 to get a motor rated to the torque
    • I still have to fit the rubber U channel to the exposed edges of the aluminium.

    I put together a rough assembly of the parts and prices that I used in case anyone was wanting to do something similar. I swapped out the motor controller I used (a $300 IBC I had lying around) with something I would have probably bought if I didn't already have one

    https://drive.google.com/file/d/0Byx_b1SCaj02cmF6eGREWUwxcUk/view

    Here's a picture of it in use!

    [​IMG]
     
  19. tasmik

    tasmik Member

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    Today as I was carrying stuff out into the hot oval while my daughter was biking around the park i was thinking damn I wish I had a chair, damn I wish I had shadowburgers truck to carry all my stuff.. half and now later, damn i wish I had a drink, a hat.. could have loaded that on shadows carrier too.. damn it.. I wants one!

    Then the walk back later carrying!!.. I want one.
     
  20. Lupuscrux

    Lupuscrux Member

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    If you go to make another one I'd look at using industrial chain and sprockets, you can get most 06B-1 and 08B-1 in plate wheels (no boss or as you called it fly wheel?) they also normal have a 1/2 or 5/8 shaft/pilot hole, chain will also be cheaper then the 428, depending on where you are i can point you to the right shop to.
     

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