Scale RC Forum Forum Members’ Builds Off-Road builds My first build – D90 custom chassis (pic heavy)

This topic contains 22 replies, has 6 voices, and was last updated by Retrocosm 1 week, 5 days ago.

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  • #104891
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    Davy Crockett
    Davy Crockett
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    Very interesting and enjoyable post…made me laugh out loud at a couple of points!!

     

     

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    #104892
    Sysop

    Retrocosm
    • Scale Off Road Pro
    • ★★★★★★

    Good stuff, those bumpers worked out a treat, even if one did fail, excellent first effort.  I didn’t understand the part about the stick welder and the microwave but it sounded like a story that could end up on the local news.  Do carry on, very entertaining.

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    #104895
    Member
    JUNGL1STM4SS1V3
    JUNGL1STM4SS1V3
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    Thanks guys. Yeah the front bumper is heavy, 231 grams. A full sized version comes out at 219kg!

    We’ve done much worse things with microwave transformers and survived. Not many of the transformers did though…

    #104908
    Member
    JUNGL1STM4SS1V3
    JUNGL1STM4SS1V3
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    Small bumper update.

    After the front bumper fell off I realised it needed changing. It was too wide and square, stopping the front tires from getting bite onto rocks.

    I spent some time thinking about what I actually wanted out of the bumper. I don’t really like the majority of bumpers out there both 1/10th and full sized, they’re very deep and chunky and I feel you lose the front end in it. I wanted something to give some protection yet allow the Defender design features to come through.

    I knew I wanted to chamfer the edges but I also wanted a bar over the grill. I decided I couldn’t weld neatly enough for that so I drilled and counter bored some holes for the bar to receive a plug weld underneath.

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    It’s a nice interference fit.

    Now I had to bend the bar…

    I have 4mm and 6mm steel round, 4mm is too small, it looks weak so 6mm it is.

    Which was a little hard to bend neatly.

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    And I still got it wrong the first time.

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    But I got there in the end.

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    At this point I still wasn’t 100% on how I was going to shape it, so I slept on it.

    The next day I found some good reference images and decided to just cut away the underside and leave it square on top.

    I cut the majority of material away with the angle grinder and finished on the belt/disc sander which took a looong time.

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    And with the bar.

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    I think it’s going to look the part, just need to weld the tabs back on tomorrow and paint it again.

    I’ve also been making a few camber gauges for real cars so not had too much time to work on this or practice welding but hopefully I can get it all sorted for Cow and Calf next Saturday.

    Oh, I also fitted a new 20kg servo, the 15kg one was struggling with the weight of this thing.

    Thanks for reading, I think I’ll make some rock sliders next and look into making a bender for cage making.

    #104918
    Member
    JUNGL1STM4SS1V3
    JUNGL1STM4SS1V3
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    So, I didn’t manage to get the bumper back on just yet, I can’t weld in the shed and it’s been raining the past few days.

    I did however get on with making a rod bender.

    Using the vice, vice grips and a spanner wasn’t really a good idea. It bent the rod sure, but not neatly or consistently, it also left gouge marks from the vice jaws.

    Like everything in this thread, I didn’t want to just buy a rod bender. They’re expensive and at the moment, I only need it for one job, once the cage is made I wont need it till I want to make another cage.

    So I asked what people had done on Facebook and someone gave me this picture.

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    Now this is my kind of home made tool, 5 parts and 4 holes…

    I had a piece of 50×8 flat, same stuff I made the skid plate out of, and someone gave me a weight lifting bar which I thought would just be steel…

    This thing:

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    Which I cut a 16″ piece off.

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    Turns out to be a 1″ cast iron bar…  Fun fact, Chronos sell 6″ pieces of this for £14, making this handle worth about £40… Oops.

    Anyway, I’m writing this post as even though it’s not strictly scale RC, it is related and was one of the largest and more interesting drilling ops I’ve done so far, so some people may find it interesting. If not, I apologise and promise ordinary RC content will continue soon.

    So I needed to put two holes through this bar, two 8mm holes…

    I decided to use this crappy X, Y table I got from Ebay. Not really had the chance to use this for anything useful, so we’ll see how accurate it can be…

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    Now it needed clamping. I don’t have clamps for these T slots that’ll hold something like this so I made one out of scrap.

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    Plenty of hold down force.

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    Easy, now onto the harder part.

    The plan was to find the centre of the bar, and use the markings on the hand wheel to advance onto the second hole.

    To find the centre I used an edge finder.

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    With which I found the edge of the bar. The edge finder has a 6mm tip and the bar is 25.37mm in diameter.

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    To move the table to the centre I measured the dovetail in the axis I wanted to move with calipers.

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    Then advanced the table 15.68mm, putting me on centre.

    I used a crappy spotting drill to start the hole and punched all the way through with a 4mm split point (If you can get your smaller drill sizes in split point, do, they’re so much nicer to use).

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    I then used the table hand wheel to advance 14mm, giving me 6mm between the pins, which should allow up to 5mm rod to be bent without too much slop.

    These hand wheel marking leave a lot to be desired…

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    You know, like actual markings…

    Also, it advances 1.25mm per rotation, so its a bit awkward.

    Shot of the spot drilled starter hole.

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    Unfortunately, I could not get the 8mm drill into the chuck, my workpiece was in the way. My drill only has 50mm travel on the quill so jobs like this need to be thought out more than I’m currently doing.

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    Anyway, I decided to leave the bar clamped to the table to keep the holes square to the quill travel and just swing the drill table out the way and prop it up on some wood. Not a good idea, as the bar’s so heavy it just wanted to tip. Also, the T slots are about 8mm, so I ran a real chance of drilling through the table once through.

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    Shit…

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    Anyway…

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    I’m sure the error is me, but I wouldn’t expect an accurate result from a table like this. It is a bit more out than I expected mind.

    Now the plate. This was easier, I centre punched and arbitrary spot and set my calipers to 14mm and marked a second hole over some marker pen and centre punched it, we’ll see how much more accurate the manual method can be for flat stuff.

    I put it in the vice for something to hold onto and did the same op, 4mm then 8mm.

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    Aaaaaand….

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    That’s within the repeat-ability of the calipers so I’m calling that dead nuts… sorry I’m metric, I mean spot on…

    And it doesn’t even really matter for this…

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    Now the pins. I’m lucky to have a local industrial fastener suppler with a public counter so I can get nearly everything including hardened ground dowel pins.

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    8mm Dia and there’s 2×50, 1×40 and 2×20, thought I’d get some spares just in case.

    These, plus 20 M3 cap heads cost less than a fiver, I think the pins were about £2.50, which is all I have invested in this tool.

    They took some heat and ‘persuasion’ to go in (probably my 8mm drill isn’t really 8mm anymore.) but it came together eventually.

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    And it works spot on, had to nip to B&Q for some 5mm rod to test it.

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    It’s gonna take some practice to keep everything flat and it fits in my vice but there’s not really enough room to do any bending around the vice but it works and I’m happy, maybe now I can stop putting off the cage fab and get on with it…

    Anyway, apologies that no RC cars featured in this post. It’s about as close to real machining as I can get in the shed without any real machine tools so it might be useful for someone.

    Thanks for reading.

    #104947
    Member
    JUNGL1STM4SS1V3
    JUNGL1STM4SS1V3
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    Part something or other: New link design, snow storm and video

    So I got the bumper back on

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    Not sure on the hoop, I’m thinking it’s a bit too high. Its just press fitted in at the moment so I can change that whenever.

    I wanted to test it before painting this time as well, just to make sure the welds held up and it didn’t have any clearance issues.

    I also thought up a new idea on links. I have a few metres of 6mm steel rod and since I’ve decided on 5mm for the cage, I had to come up with a use for it. I wanted to make links and ideally, I’d turn down a portion at either end to 4mm on a lathe and thread for M4, but again, I don’t have a lathe. But I do now have a welder…

    I figured I could drill into the ends of the rod, then cross drill through those holes, insert a small piece of thread rod and plug weld the cross holes. I did a quick concept for the front steering arm, ground the weld buildup down with a combination of a belt sander and drill and gave it a polish. I think it turned out great, although I’ll most likely go for a painted finish to hold back rust.

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    I’m going to do all the links on the car with this method and I’ll document the process in a subsequent post. The original link with short rod ends weighed in at 11g and the new one with long rod ends 24g, I like weight so I’m doing the whole truck but I think just lower links might be a worthy upgrade for most trucks.

    Anyway, with the new bumper and new link installed, it was almost time for Cow and Calf again.

    Before viewing these pictures, remember this is an hour and a half drive for me, once I was there I was going out rain or shine…

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    Gooder place as any to stop for a sarnie.

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    Smaller turnout than last time for some reason…

    Meet lasted from about 10 till half 1, then this greeted me leaving the car park after everyone went home.

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    Couldn’t make it up…

    The car did great though, other than an intermittent power stutter that seems to be getting worse, not sure if its the motor or ESC so I’ll probably change both next. The bumper has reduced entry angle a bit, which made some climbs harder that others weren’t struggling with, I may sweep it back towards the edges, not sure yet. New link did fine, wasn’t expecting much else.

    The only unfortunate casualty was the windscreen.

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    So I’ll be on the lookout for a replacement at some point.

    The next day, I took a colleague out with the car and a camera. He has both an interest in models and an interest in learning a bit about camera work so I hooked him up with a manual camera and took him up the moors and asked him to film for me. Bear in mind he’s never really filmed anything before, never used a manual camera and had me shouting technical jargon at him from afar I think he did pretty good.

    Anyway, please enjoy seven and a half slow minutes of a completely deflated front left…

    I hate trying to film a drive by myself, it’s nice to have someone do it for you.

    I have a tire problem, the front left seems to have a leak where the weight of the car deflates it but the springy-ness of the rubber isn’t enough to draw air back in. Going to have to try and fix it this week, its shrinking even more in the cold and hampering performance…

    I apologise immediately for that very crudely disguised joke… That’s it for now, when it dries up and I can weld outside I’ll make the links, even if just to put off cage making for a bit longer…

    Thanks for reading.

    #104956
    Member
    JUNGL1STM4SS1V3
    JUNGL1STM4SS1V3
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    Today I made some scale accessories.

    I cut up some wood and made some straps, scale 2×4’s and 25mm ply

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    And a roll of gaffer tape

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    Not sure what he’s building, maybe a new shed…

    I think it looks decent, might change the wood around a bit, maybe stain or oil it as it’s looking a bit pale at the moment.

    #104958
    Sysop

    Retrocosm
    • Scale Off Road Pro
    • ★★★★★★

    Very nice, loving those links, should add a good bit of weight low down.  Cool video too, very nicely filmed.

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