Dogati Electric Superleggera

Like Marko said, very impressive. Those welds are amazing for a beginner – working hot and fast like that takes a lot of dexterity.

I must have missed something. I thought you were using a planetary reduction, but isn't that a g-box or the like that your frame is bolted to?
 
Malcolm said:
Like Marko said, very impressive. Those welds are amazing for a beginner – working hot and fast like that takes a lot of dexterity.

I must have missed something. I thought you were using a planetary reduction, but isn't that a g-box or the like that your frame is bolted to?
Click to expand...

thanks for the encouragement guys. the first half of the frame was pretty bad, but i learned from my mistakes and the 2nd half turned out less sucky :)

very observant malcolm. yes, the new system will still have two planetary stages, but instead of the compact "inline" design, i've distributed the gearbox, motor, freewheels and bearings (sandwiched between the 2 carrier plates like a g-box). this takes up less width and i can use longer motors or even put my magnetic clutch in there. on my old drive, anything bigger than an astro 3210 wouldn't fit between the cranks.
 
I made a tube notching attachment for my lathe. Tried to make it simple for rigidity. Just some 6061 angle plate and a metal protractor bolted on top and slotted out. The base swivels and locks at two points to prevent it from shifting. Made a series of clamp holes so that they can be moved around to notch at weird angles or on bends. Swivels 70 degrees in either direction but no offset notching (to keep it simple). A bent filler rod painted red serves as the degree pointer. Notcher bolts on top of my existing quick-change tool-holder base (so i don't have to spend too much time changing between tool-holder and notcher).

I use diamond grit hole saws and run them at 3350 rpm with a water based mist coolant. Cuts thru the thin-wall tubes like butter--smooth and no tearing. Notches come out perfectly formed and edges are razor sharp (gotta be careful). These hole saws do a better job than bi-metal ones for sharp acute angled cuts.

DSC00715.JPG
 
subscribed!
 
swing-arm partially jigged, with bosses in place (they remind me of the nunchakus i used to make as a kid). the 3rd boss (at the bottom) is 6061 aluminum. not sure if it will work, but i am going to try and plug-weld that. however, i'm afraid they will work themselves loose since the weld is not actually penetrating the chromoly tube. but there is a significant weight advantage--aluminum boss is 23g, steel ones are 70g.

 
Malcolm said:
Looking better all the time. Is there a particular reason for making the lower boss out of aluminium or is it just an experiment to see if it can be done?
Click to expand...

major weight savings (23g vs 70g). with 6 bosses, that's (138g vs 420g). yes it's an experiment (although i am pessimistic). the boss slides 10mm into the tube. i was going to drill 4 holes in the tube and plug-weld the holes with AL filler. AL won't weld with the chromoly since they are dissimilar metals but i was hoping it would be enough to keep the boss in place. then i would sand the plugs flush with the tube. having second thoughts though. i think the soft AL plugs would eventually fail (and my dropouts would literally drop out). so i'll do some brute force tests on them. if they go belly up, i'll drill them out and tap them for small M3 button head cap screws (or just replace with steel boss).
 
I think the aluminium plug welds are likely to shear and work loose, as you say. Bonding might be more successful, but with only 10 mm of overlap I'm not sure this would be ideal either. Personally I'd look for ways to lighten the steel bosses. This is such a critical area I'd accept a small weight penalty. Don't let me put you off experimenting though :)
 
Miles said:
If you bond, you'd use more overlap. No, not JB Weld! :) True, it would have to be the last operation..

Are the steel ones drilled out?
Click to expand...

i think malcolm is right...i should focus on lightening the steel bosses. the boss is not bored out, but that's a good idea--i'll try that and see how much weight i saved. thanks for your suggestions guys. still a long way to go before this is done. the swing-arm is turning out to be even more of a nightmare than the frame! the tight compound bends had me on the ropes so i had to scrap those--my bender just couldn't do it. also too much chatter notching on my tiny lathe (and it would loosen up all my gibs) so had to get one of these monsters: http://www.vansantent.com/tube_coping_machines/JD2_Beast_Notcher.htm. 50 lbs of heaven for holesaws :twisted:
 
my toy lathe/notcher just wouldn't cut the muster so...enter the beast. this thing is built like an M1 abrams. big reason i bought this--the backplate. it is machined from 1 1/2 inch solid steel. i'm going to repurpose it as a vertical fixture table when it's not doing duty as a notcher for my puny tubes. you'd laugh if you saw an 18mm holesaw on this thing--doesn't do it any justice :D haven't weighed the sucker but it feels heavier than my bike (70lbs). hell, the spindle probably weighs more than my frame. gotta go eat some spinach now, blood sugar running low after lugging this up the stairs.

update: made my virgin cut and was blown away! using fine pitch (10tpi) bi-metal saw on 7/8" 1.2mm chromoly--hole-y moly 3 seconds flat!

DSC00722.JPG
 
Superb job thus far j3tch1u, welds look fantastic also! Ducati should of
paid you to design/build them a Ducati Downhill MTB as your frame looks
SO Ducati like...I must build me one like it!

KiM
 
AussieJester said:
Superb job thus far j3tch1u, welds look fantastic also! Ducati should of
paid you to design/build them a Ducati Downhill MTB as your frame looks
SO Ducati like...I must build me one like it!

KiM
Click to expand...


thanks kim! if you do a ducati style ride, i would surely cheer you on. the trellis is so rigid--should take any motor you throw at it. tons of trunk (you guys say boot?) space as well. as for a sponsorship, well umm not suing me is good enough :lol:

i hope to graduate to e-motos in due corse. motoczysz is a great inspiration--the level of refinement from such a small team. as for now, armed with the tools and just enough know-how to be dangerous hehe...
 
j3tch1u said:
as for now, armed with the tools and just enough know-how to be dangerous hehe...
Click to expand...

You have the means and know how to take the e-motos to the next level , look forward to watching it happen :)

KiM
 
Great design! I'm weighed down by Your back-up facilities. Are those small planetary gears on the begining of this thread strong enough to work with astro motor. Their max (output?) torque is 300 lb-in, and according to astros site output torque is up to 500 lb-in. Or I'm missing something?

Greetings, Robert
 
robert.smu said:
Great design! I'm weighed down by Your back-up facilities. Are those small planetary gears on the begining of this thread strong enough to work with astro motor. Their max (output?) torque is 300 lb-in, and according to astros site output torque is up to 500 lb-in. Or I'm missing something?

Greetings, Robert
Click to expand...

hi robert, thank you for the compliment. yes, those matex gears are tough little bastards and if they break, they're easy enough to swap out. i think the astro spec is 500 ounce/inch for 1 minute (ie. 31 lb/in) :D
 
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