Fizzit's RC freeride build log - now with videos

[Hillhater]

Sure the position of the bolts will support the shaft to a certain extent , but mainly only in the one direction, and only back to the single mount plate hung from the frame tube.
The sprocket is going to try to twist itself in any direction it can find movement so its better to secure it as much as possible..
Why are you reluctant to fit the second support plate,? its a simple addition and a much more rigid support for the whole drive assy & sprocket shaft.

[dequinox]

Hmmm... what to do???

Hillhater, are you saying that the bearing flange will bend between the bearing and the bolt or the bolt threads will strip? Because that's the only way I can really see it flexing, barring the spacers deforming. The chain loads will be completely pulling towards one of the bolts on one side and away from that bolt on the other, the only reason the bearings are rotated 45 degrees on the mockup is because I countersunk the wrong side the first time I drilled the bolt holes

AJ, I wish it were that easy! The pictures don't show it, but the tube is oval shaped

The bolts will hold everything together fairly secure, but you may need to adjust from time to time. Below is an image I conjured up of the idea I was talking about as applied to your bike. Let me know if any part of it is confusing. KEEP IN MIND: You need to make some part of this thing adjustable for chain tension, or be prepared to add a chain tensioner wheel or drag tensioner like in my video. Its fairly difficult to plate the motor mount with the exact right distance between sprocket centers. Besides, its nice to have some adjust-ability in case things aren't working quite right. Good luck cutting up that aluminum tomorrow. PS the image on the right is a view similar to the last photo you posted...and also the top 5 bolt locations I suggested are wrong...they should be centered on the oval tube which is the black outline in that picture.

Fizzits motor mount.jpg

(187.54 KiB) Downloaded 3 times

For some reason this dirty rat-bastard of a picture isn't showing up directly...I'm not sure why. Sometimes they show up right in the thread and sometimes they don't

[fizzit]

Thanks for that picture! Took me a little while to understand the one on the left though
I think I get what you guys are saying. Hillhater, I was a little reluctant because it seems like the other plate could move around since the tube is rounded, but if I do a spacer-type thing like dequinox shows, that problem should go away. I just wasn't sure about the whole application of it, but now I see more clearly how it could go together.

[dequinox]

Yeah just food for though fizzit. Heck you could even add the second plate later if you felt you needed to, thats the beauty of this type of build is that it's not set in stone, and you can always play with it a little.

[fizzit]

More progress

I cut through the aluminum. 8" of 3/8" aluminum with a dull hack saw, that was fun

And below, you see the n00bish results of my handiwork. Along with a prototype sandwich plate on the other side, made of wood, just to get the hole spacing down. The bolts on either side of the tube aren't installed in the picture, it's being held on by two bolts through the tube. I need more bolts
Any opinions on what I've done so far are appreciated!





Hopefully you can see my hacked-together chain tensioning system for the small chain. It better hold up . As far as chains go, I've been informed that my hacked #40 sprocket needs work. I agree But still, I lack the skills/tools to make one that I'm truly comfortable using regularly. So I'm wondering. Does anyone have any idea how I can get a 11-or-so-tooth bike chain sprocket onto a .5" shaft? I'm open for any ideas, even for having someone machine another #40 sprocket for me. however, I want to keep it under $25 if I can, and with that budget I think machining is out

PS. My freewheel finally got here, guess what, it doesn't clear my bottom bracket. Luckily, I anticipated this problem and bought a 158mm spindle to replace my short one with! Unluckily, I assumed that if you could buy replacement spindles, its possible to replace your spindle, which it apparently isn't. Also, 158mm is really way too long. So it looks like I'll be spending another $25 on a SBP bottom bracket and a few more $ to get the current one replaced. Oh well!

[dequinox]

Lol not bad looking for a dull hack saw. I think it will work! The idea behind the sandwich plate, though, is that you bring it down far enough to mount the other bearing to. Cut a hole in it for the motor...or just leave a corner off or something like that.

Does anyone have any idea how I can get a 11-or-so-tooth bike chain sprocket onto a .5" shaft? I'm open for any ideas, even for having someone machine another #40 sprocket for me. however, I want to keep it under $25 if I can, and with that budget I think machining is out

$9.60 at McMaster-Carr: http://www.mcmaster.com/#drive-sprockets/=9jxfxz
or $13.44 if you want hardened teeth. I don't know what shipping is... but they even have 9 tooth sprockets for a 1/2" shaft.

[fizzit]

Lol not bad looking for a dull hack saw. I think it will work! The idea behind the sandwich plate, though, is that you bring it down far enough to mount the other bearing to. Cut a hole in it for the motor...or just leave a corner off or something like that.

I'm glad you think it will work ! Yeah I may do that with the plate, the wooden one is definitely not permanent, so for right now I'm just seeing where things go.

$9.60 at McMaster-Carr: http://www.mcmaster.com/#drive-sprockets/=9jxfxz
or $13.44 if you want hardened teeth. I don't know what shipping is... but they even have 9 tooth sprockets for a 1/2" shaft.

Correct me if I'm wrong, but it doesn't look to me like Mcmaster stocks sprockets with teeth that are bicycle-chain thickness

[dequinox]

I'm not sure what the thickness of the teeth is on those sprockets. If bicycle chain is in fact #40 (I've never researched that ironically) they have the right pitch available. What width of chain are you using? 1/8" or 3/32"? Their detail drawing doesn't provide the thickness of the teeth.

[Miles]

#40 chain has the same pitch & roller dia. as bicycle chain but it is much wider.
Dimensions here: http://www.gizmology.net/sprockets.htm

[fizzit]

#40 chain has the same pitch & roller dia. as bicycle chain but it is much wider.
Dimensions here: http://www.gizmology.net/sprockets.htm

Yup. So what I did before, is I bought a 11T #40 1/2" bore sprocket from mcmaster and dremeled the teeth down to be bicycle-chain thickness. However, I don't have a lathe so I couldn't do it particularly well and I am looking to replace my sprocket with a better-made one. I think I may just buy another and take it to the metal shop at school and see if they'll let me use their lathe.

[Solcar]

Fizzit, I have used a hand drill to turn items that need shaving with some success. Alternately, securing it on a motor might work. It has to spin with enough torque to keep spinning under the friction of grinding or cutting.

[spinningmagnets]

Similar to one of Thuds projects? whether you are driving the Bottom-Bracket or rear wheel, I am seeing more of these boxed RC-single-stage reductions.



This is Mud2005's RC-MTB:

[fizzit]

Similar to one of Thuds projects? whether you are driving the Bottom-Bracket or rear wheel, I am seeing more of these boxed RC-single-stage reductions.



This is Mud2005's RC-MTB:

I've seen those, they're really nice. The 2nd one is my favorite, but the first is more what mine will be like as it drives through the cranks. However, mine will need to be a bit better enclosed as I'll be riding in the rain quite often

[fizzit]

Just won a new HV160 off ebay for $207.50

Also now pretty much out of money, at least 3 days till the next thing I sell on ebay ends

[fizzit]

So... I was looking around on eBay for a good bike lock, and I found a Onguard Mastiff 5020 that was about to end (I agree, massive overkill) and I won it for $1.56 (that's not a typo) plus $10 shipping... perfect seller feed back... brand new lock... is there something I'm missing?

In other news, I made the other side of the sandwich! It holds the other bearing nicely
To even out my sprocket, I managed to get it on my drill press and file it. Thanks for the inspiration, guys! For the secondary chain, I got 1/8" BMX chain. It's yellow. That's all for now, once I get the other plate mounted I'll post pictures

[fizzit]

I made the other plate from aluminum, with the same hack saw. Fun as hell

Exhibit A:


This is what my bike looks like right now. It is hanging from the ceiling, I'm not really sure why.

B:


C:


I assure you, the rubber bands on the chain tensioner are temporary

D:


Comments, criticisms appreciated!

[amberwolf]

This is what my bike looks like right now. It is hanging from the ceiling, I'm not really sure why.

Maybe it watched too much Addams Family.

[dequinox]

Not bad fizzit, you're a hand-tool machine man! I'd put a spacer block for extra strength on the bottom of your "sandwich". Could just be made of wood, and would be as wide as the bike frame tube. Let us know when you get 'er working!

[AussieJester]

Might just be the camera playing tricks but the chain alignment looks a lil skewif to me..
whack a chain on it stand back and let her rip & see how she goes

KiM

[fizzit]

@amberwolf:

@dequinox: I will do that. I just have to make sure it's the perfect width!

@AJ: My HV160 just got here so I will be testing the chains very soon Although it will be on 6s so at half speed. I agree I need to work on the chain alignment a bit.

My ESC and lock got here on the same day! I can't believe I got this lock for $2, it's pretty crazy. It works great. It came with 5 keys, one lighted. Just the lock itself is about the size of my fist and the chain, like they said, is 10lbs. I'm wearing it as a necklace right now. Although it's starting to hurt my back a lot so I think I'll take it off...

Oh yeah and the ESC is pretty too

Edit: I'm just wondering. How to you guys think my motor (HXT 200kv 63-74) will fare at 44v with my 160? My gear ratio will be around 20-to-1. I remember a lot of people saying that these motors are meant to be overvolted and that they are highly efficient at higher RPMs, but will my setup take advantage of this? Any input appreciated as I don't really want to blow up the motor

[fizzit]

I just received 5 of these caps:
http://www.mouser.com/ProductDetail/Pan ... KoOw%3d%3d

Should give me a cool 15 amps of ripple current handling
I'm expecting a small mushroom cloud whenever I hook the controller up, at least until I get together a no-spark circuit

Oh and I found a nice extruded aluminum hard drive enclosure that I think i'll be using for the controller/electronics enclosure. It even has a fan on the bottom. I'll post pictures once I've hacked it some more

[fizzit]

So here's my enclosure/ wiring. You can never post too many pictures of a box






I bent a piece of plexiglass to fit over the ESC


Everything crammed inside, with the throttle converter, watt meter, 5 low esr caps, and ESC.

I also made another chain tensioner. I think it's a lot better

[AussieJester]

Wholey snappin' duck shit would ya checkout the caps
Nice job on the conneting of them, i would offer one small suggestion though, move them as close to the ESC as you can possibly get them, its been drummed into me by a few of the gurus here how important it is to have them close to the ESC to be effective... Have you bought the data link cable to program the HV160?

Look forward to this running hurry the hell up will ya hehehe

KiM

[recumpence]

Yup, move them caps REALLY close. I mean, like an inch of wire from the board if at all possible. It makes big difference.

Looks good!

Matt

[fizzit]

Thanks guys! I moved the caps. And redid all the solder joints for good measure, cuz they sucked.



They are not quite 1" away, but they're 4" away. which is half the previous distance. I hope thats good enough for now

I'm guessing 3 weeks until I can afford batteries and they arrive. And finally, I'll be able to test it out. I'll probably find time to write my will this weekend