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Ondray
Joined: 06 Jul 2015
Posts: 142
Location: Newcastle
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The goal of this weekend was to find a way to mount the the 130mm white wheels from funnings. They have a 3/8 hole which is a touch too big for the shaft on the motor. I thought the driveshaft had a M10 thread on it because I tapped out the 90mm red wheels to M10 and they seemed to screw on.
Last weekend I tried to use the plastic adapter sleeves from the wheel section in funnings. I'd tapped out the white wheels to M12 and had this (dumb in retrospect) idea of making a thread converter going from M10 inner to M12 outer. Didn't work because the plastic wound up too thin and they broke during construction. I really was trying to do it that hardest way possible.
This weekend I went into the nearby hardware store, wit the plan of getting metal M12 bolts to drill hollow then tap the inside. I told the hardware guy my plan, we both agreed it sucked and he directed me at some M10 drop in anchors that seemed perfect. But of coarse this is where I find out the thread isn't M10, the metal thread on the anchor wasn't as compliant as the plastic on the red wheels and so that didn't work.
Thus I hunted around Newcastle's hardware stores to find out a: what the thread on these shafts is and b: if I can get any nuts that'll fit it. I managed to figure out that they are 3/8 UNF - but no-one in Newy had any 3/8 UNF bits. So I bought a full imperial tap and die set to get the one tap I wanted (I've wanted an imperial set ever since I got the metric one).
New plan was to use the adapter sleeves with the inner tapped and drill the axle on the wheel out to a snug 12mm and epoxy the sleeves in. Looks like it'll work, I just have to wait for this crud epoxy to dry. I got the cheap brand of epoxy at funnings and it's taking forever to set, I had the same problem with the last epoxy I used - which was also cheap. So next purchase will be some Araldite which has always served me well in the past. But the sleeves fit well and the motors screw nicely into the 3/8 UNF and there's space for me to put the little reverse thread screw down with a washer. I feel good now I've got this sorted.
Next step was cutting out more parts from the frame, which was really nice to do outside on Saturday arvo - not to mention partially necessary due to the lack of space and power in my shed.
The motor mounts now have a beefier section that will support the drive shaft and gearbox and the ESC and battery housings are cut. It's starting to get so dense with Al section it's hardly going to need the polycarb top and bottom!
The next job was to use some Al L-section and steel L-brackets to screw it all together. So I got up early today, headed outside and saw a storm from rolling in Because I have to run an extension cord from the house to the shed I don't like working in the wet. Especially the amount of rain today, so instead I schmicked up all the wiring - my solder station is inside the house...
I'm pretty chuffed with how it turned out. The ESC bundle will be wrapped in bubble wrap and placed inside a bit of Al section. There's an old bicycle tube to protect the cables that will run between the two halves of the bot. I even used cable ties to tie cables! I think it's the first time ever I've used them for their 'intended' purpose.
I also ordered some v-tail mixers, the sprocket set from my last post, some RC controlled switches to do lights and some little 6V gear motors so I can build and Ant. On the mixing, there's a FB group for the turnigy/flysky users and from them it sounds like I can't do 4 mixes.
Next weekend if it's not dry I'm going to use my Dads shed lol. Hopefully I can get it driving.
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Sun Apr 17, 2016 9:18 pm |
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Ondray
Joined: 06 Jul 2015
Posts: 142
Location: Newcastle
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Nice, 04C and #25 being the same gives me more options. I did go to a bearing place here in Newy, but the guy really didn't have anything small - the industrial suppliers here are very industrial.
This longish weekend saw a lot of progress, but the two steps forward one step back kind...
I got some Al L-section to hold most of it together rather than the steel L-brackets as the longer pieces should be stronger - but more importantly my oversight with the L-brackets was that I physically couldn't put half of them in the inside corners with the bot being assembled. The L-section goes on the outside overcoming this issue.
Next was getting the sprocket to drive from the window motor...the best I could come up with was trying to cut grooves into the shaft of the sprocket so it could fit into the slot in the window motor like the original cog did. The only means of doing that that I have is to cut it freehand with the rotary tool...I wasn't anticipating success...So I used some purple nail polish on the slot to mark the cutting points on the sprocket and away I went:
It started to work, then I broke the $20 tungsten carbide cutting bit. As you can see I made a fair bot of progress on the first sprocket and it slides a small way into the slot, a new bit and more carefulness and it might actually work! I think I might start looking on gumtree for a mill though.
Next was a much easier job, making the gearbox bracket for the gearmotors. I embedded the bearings in some HDPE (chopping board):
At least this went smoothly! Fit perfect. Then I bolted the bearing bracket in to make the drill nice and happy:
I then done some more drilling and screwing to get the driving chassis together, I'm rather chuffed:
And a video of the first test drive, I've got some practice to do...
https://youtu.be/gaQFG37pmOU
Once I've got the sprockets into the window motors all I've got to do is setup the lifting arms, put the polycarb on and give it a good polish!
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Mon Apr 25, 2016 10:19 pm |
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