Rango - Build diary

[Ellis]

Hah, cheers PJ. The amount of time that goes into doing this stuff by hand is surprising, I want a mill! But:

I made that plate by scribing the dimensions on the raw material and cutting it out with a hacksaw, then filing to size. I marked the positions of the centre hole with more scribing (from the edges), centre punch, then drill, then used a 25mm forstner wood working bit to scribe the radius for the bolt pattern from that centre hole. Find what should be the distance from the edges of the piece for the holes (cad helps for this) and scribe from all sides, giving me the hole positions along the previously scribed bolt circle line. Centre punch, drill, countersink, bish bash, rub the finished product with some wirewool to get the ugly raw material finish and scribe lines off and ya done.

-Ellis' life story 2014

tl;dr: scribe the everything. I don't know how I/we managed to build anything without scribes and centre punches, lol.

[PJ-27]

Finding the centre of the holes for the 4 bolts is the tricky part (if you don't have a mill) marking a cricle is genius!

Sounds like you want a Trepanning tool, but using a Forster bit is also some bodge genius!

[Ellis]

Never heard of a trepanning tool, had to look that up!

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Bit of an update on parts. A few days ago my dad and I went halves on a Spektrum dx6i and a pair of orange receivers, which will make things a lot cheaper in the long run. Also means T2 and Rango can be driven in the same competition which is the intention for April.

I made an unexpectedly large order from Hobbyking. I needed to buy a brushless speedo anyway, and having found out a bit more about this motor's history from Jamie, the likelihood is it won't last all that long. Since HK stuff is so cheap I bought a replacement/back up; a Turnigy SK3 3968, an inrunner. Should push 2kw, which to send this little drum to 8-9k should be ample. I was mostly swayed by the 8mm shaft with a flat, which is perfect for my pulley setup. I got a 150a YEP speedo, pretty generic, will be interesting to see how it does. Motor too I guess, HK stuff seems to always be a gamble! Oh and some 10awg flexible wire.

Today I bought an Optipower LiPo. Again, a pretty standard battery; 30C, 4300mah, 5s. Not sure how true the 80C burst rating is but even if it's half that it should provide plenty of grunt for both drive motors and the weapon. Roboteer's discount on that was very welcome.

Also grabbed a pair of forstner bits for drilling the pockets the armour supports and drive shafts sit into in the HDPE, and a load of fine grit sand paper for stock.

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The aforementioned armour supports. 110x18, with an m8 thread in each end.

[harry hills]

It's so shiny I'm gonna die!

Nice work mate

[grant_ploughbot]

You will be able to use the full rating of the Opti packs

[Ellis]

Glad to hear it!

edit: bulkheads have been machined, hopefully posted to me tomorrow. Am expecting them to be here by next Monday or so.

[Ellis]

Stuff!

Meanwhile, I'm making the wheels. Super slow process, lots and lots of nylon to eat through. Am hoping to have the wheel-stuff done by the end of the weekend. Chances are good that the bulkheads will arrive whilst I have to concentrate on something else next week, which, naturally, will make it impossible to focus!

[mrsam]

Is that a different brushless to the one you had originally?, can't wait to see how this build progresses

[PJ-27]

Who's funding your build now!? Bill Gates!?

[Ellis]

@Sam: yeah it's a different brushless. The other I'll keep as a spare. This new one is shiny but not "quality", it's a Hobbyking job. :P

@PJ: I am! Been saving up, lots!