An Advanced Friction Drive System

[Kepler]

May I ask how you tapped those holes? I hate using a tap wrench and doing the old 3/4 turn forward, 1/2 turn back, 3/4 turn forward thing. I keep thinking that there must be a way to use the drill press to just power it in, but I haven't found anything like that.
Katou

When I was toolmaking (er.. almost 40years ago), we used tapping heads in drills, lathes etc, and kerosene as the lubricant for aluminium. Things must have progressed since then!

Cheers,
GT

I'm sure that’s still used in a commercial setup. For us hobby machinists though, lube in a spray can and a simple drill press and tap wrench does the job fine

 

[Kepler]

Getting closer to completion now. Electronics are now fitted off and shoehorned into position. The bottom section contains the servo tester circuit and BEC to power up the speed controller. In the top section where the ESC is there are also a couple of trim pots to set the speed limit on each of the speed settings. I have decided to fabricate new swing arm plates rather then re use plates from the Mk1 drive so there's another evening's work to do there.

 

[gtadmin]

I'm sure that’s still used in a commercial setup. For us hobby machinists though, lube in a spray can and a simple drill press and tap wrench does the job fine

Of course and that's how I would do it now (not having access to all the goodies), but I thought alternatives were being sought for a great number of tapped holes. Anyway, just make sure you use enough lube because ali gets like 'hot-welded' to the tap easily, which then strips the thread. Better to be safe than sorry

Cheers,
GT

 

[gtadmin]

Also, I failed to mention that I like your drive! Nice and simple. An unusual part of this is a mech eng that can also build it

Cheers,
GT

 

[katou]

Re tapping, yes, gtadmin, you are correct, I was looking for alternatives to the old drill press and tap wrench method. I hate that method, so kludgy and slow. But it works, and it's what I do for any tap smaller than 5/16, otherwise I cross thread and snap taps off in the hole. Nothing much more frustrating than that. Especially on the last of 10 or so tapped holes. I have a handle that I add to the chuck so that the whole chuck becomes my tap wrench, I do the whole thing in the drill press.

This is for lurkers who don't know what I mean, the drill press is OFF - NO POWER - we just use the drill press to position the tap, and hold it so it goes into the hole straight.

Anyway, I went off what you wrote gtadmin, and it looks like the Tapmatic 30x or 50x is the way to go. To be had on Ebay for around $200. Automatically reversing clutch, best tool for it is apparently the helical flute tap (looks like a drill bit but with threads)

That's one reason I like aluminum, it's a bit more forgiving for the tapping.

The (nearly) fully assembled unit looks very much like the drawing, well done! If you have some before-and-after comparisons, that would be great. Weight, ease of mounting, etc.

Katou

 

[mwkeefer]

I keep thinking that thing is bulky, then I look at my HV110 and I realize how tiny it is in reality by scale...

Kemper, you need to hold it near or mount it to your bike for pics, it will give a better impression of scale = )_

Very nice work... I was looking for suitable motors at HK but they are sold out of everything with proper bearings it seems... guess it's time to await reorder stock, I want to attempt a similar (read that as Knock Off) design but made with hardwood instead of metal and pushing a max of 1HP output..

-Mike

 

[Kepler]

Your right Mike, the photos so far give the impression that the drive is quite bulky I think mainly due to its very square and sharp proportions. The drive is nearly completed now though so I will be able to post some pictures of the drive mounted on the bike to show just how compact it really is.

Completed the new swing arms last night. With this part out of the way, I should be able to complete the final assembly tonight. Then it all comes apart again and off to the anodizers for the finishing touches.

 

[spinningmagnets]

Kepler, no matter how wonderful something may be, there always seems to be some small thing I would change slightly to please my personal preferences...that being said, I feel that your drive is so well-thought out and well-executed, I wouldn't change a thing. If I made a friction-drive someday soon, I think I would like to copy this. (though I must confess, I think EVtodds roller-drive would be easier to make)

Since batteries would be brought indoors for charging, the entire drive/controller/batt-pack could be a single detachable unit. It could be contained inside a bottomless luggage bag that looks very stealth (bag interior fan-cooled). Such a bag should make the unit run quieter (though likely not as 'silent' as I'd like)

I'm pondering a battery-powered wireless throttle (I am very weak at electronics theory, but I think it "should" be possible...Fechter?)

 

[amberwolf]

Easiest way for wireless throttle if using an RC controller is to literally use an RC throttle control, and an RC receiver at the controller. Then you have no electronics to figure out, other than mechanically adapting the RC throttle/sender to your handlebars in a way that lets you use it easily, and whatever wiring is necessary for this.

I don't trust wireless enough to use it to control a bike, though, since there are too many possible interference sources. I might not mind using it to send data from controller/etc to a "dashboard" display, but I wouldn't want to trust it to send data back to the controller. Call me paranoid. :lol:

 

[AussieJester]

I don't trust wireless enough to use it to control a bike, though, since there are too many possible interference sources.

I wouldnt do it either but if i sis i would go with a 2.4ghz system less chance of interferrence. A lanard connected to your wrist and a pull out kill switch (same as speedway an drag bikes use) would also be advisable if something went wrong would be quick and easy to kill the system.


KiM

 

[mwkeefer]

Let's not forget using the left side shifter mechanically coupled to either a servo tester or some throttle - in theory I guess you could just make a cable mount for the main body of the friction drive, run the cable through and whalla!

I have to concur with spinningmanets, you've done an all out fantastic job on this system (so when are units available?) and the only reason I may go with a roller type and a timing chain or belt would be that I can't find appropriate low kv motors with adequate bearings - and I have some junk tower pros on hand which will work well but not the can as a roller.

About units for sale, I know they take u a while by hand but without a motor I can see these commanding 100-200 just for the assembly... You should give it some thought

-Mike

 

[Kepler]

Well the drive is finished and has been test run with no issues showing up on the bike. Here are a couple shots of the finished unit comparing it with the original unit. I think half the size would be a fair estimate plus the added bonus of being around 200 grams lighter.

 

[Kepler]

Here are a couple of shots of the drive fitted to the bike. I have now stripped it down completely and taken all aluminium parts to the anodizers. Should have the parts back mid next week ready for final assembly. I have layed out the parts to give people an idea on what the parts count actually is. Counting all the fasteners, there are just over 100 parts to make up the mechanical side of the drive.

 

[Kepler]

Kepler, no matter how wonderful something may be, there always seems to be some small thing I would change slightly to please my personal preferences...that being said, I feel that your drive is so well-thought out and well-executed, I wouldn't change a thing. If I made a friction-drive someday soon, I think I would like to copy this. (though I must confess, I think EVtodds roller-drive would be easier to make)

Since batteries would be brought indoors for charging, the entire drive/controller/batt-pack could be a single detachable unit. It could be contained inside a bottomless luggage bag that looks very stealth (bag interior fan-cooled). Such a bag should make the unit run quieter (though likely not as 'silent' as I'd like)

I'm pondering a battery-powered wireless throttle (I am very weak at electronics theory, but I think it "should" be possible...Fechter?)

Thanks Spinningmagnets, much appriciated. In relation to being a single detachable unit, that certainly would be an easy addition. This drive has a nice flat surface on top which would lend itself nicely to mounting a single 5000 mah pack. I personally like the two items separate as I like to keep my options open to what size pack I am using.

 

[mwkeefer]

Looks great!

One thing... you may want to cover that lipo pack with say... maybe a fake or cutout water bottle. To me it looked like a compressed brick of weed, to my friend it looked like a brick of C4... either one would get you the kind of attention we know you don't want!

Seriously though I see the potential for a custom rear rack that covers and hides the whole setup ??

-Mike

 

[Kepler]

Let's not forget using the left side shifter mechanically coupled to either a servo tester or some throttle - in theory I guess you could just make a cable mount for the main body of the friction drive, run the cable through and whalla!

I have to concur with spinningmanets, you've done an all out fantastic job on this system (so when are units available?) and the only reason I may go with a roller type and a timing chain or belt would be that I can't find appropriate low kv motors with adequate bearings - and I have some junk tower pros on hand which will work well but not the can as a roller.

About units for sale, I know they take u a while by hand but without a motor I can see these commanding 100-200 just for the assembly... You should give it some thought

-Mike

Thanks also Mike.

In relation to producing and selling, the problem is that this design is bike specific so I would need to design a universal type mount if i was going to start producing these. Worth thinking about though for those who dont have the facilities to fabricate this type of thing. For those who can fabricate I plan to post up as built drawings to finish off this what has now become a build log.

 

[EVTodd]

Looks great! I can't wait to see a video of this version.

I'm so jealous of anyone that has a local anodizing shop. I can't find one within 200 miles of where I live.

I agree that it would nice to have a friction drive setup actually produced for people that can't make one. I've been approached by a few people about my drive too. I actually thought about doing it for a bit but I'm still not sure I'm ready to get into the ebike market. If I did I would probably just make the sliding mount portion and let people modify it for their bikes. Of course that still wouldn't be a turn key solution but as you said, fitment to different bikes would be an issue.

 

[Kepler]

I am lucky enough to have an anodizing shop on 15 minutes away so thats very handy. Will cost $50 for all aluminium parts to be coated. Well worth it think to really finish off a project.

I want to do a video of the drive in such away that it has both the drive and a forward view of the road in shot. Just need to figure out how to make a suitable mount.

 

[katou]

Dude, that is beautiful.

"Perfection is reached, not when there is no longer anything to add, but when there is no longer anything to take away."

-Antoine de Saint-Exupery (author of Le Petit Prince)

So impressed, this is so pro, in design, execution, even in presentation, I hope that my drive works half as well. When I show my friend who is looking for something ultra small and light, he'll be blown away.

My hat's off to you, thank you so much for sharing. I'm copying this whole thread into my archives.

Katou

 

[evblazer]

You know. My drive looked awful before now it just looks ____. I don't know I can't think of a word to properly describe it compared to that new piece of highly functional bling you have there.
Also that motor, tiny as it is, looks HUGE compared to the rest of the parts you got laying out there. Oh and yeah definately pretty up that lipo pack would it fit in a seat bag? I don't think I'd get very far without hearing sirens with something like that if the cops found me before the locals.

 

[Kepler]

Thanks for the kind words guys. Makes it much easier to keep up the documentation side when people are genuinely interested.

In relation to the pack, people don't look twice at the pack down here in Aus. The thought that it might be something threatening or illegal doesn’t come into play at all. That being said, point taken and I think I will probably go down the drink bottle holder path. Will certainly enhance the look of the bike and be a useful addition with or without the drive onboard.

 

[adrian_sm]

Grinhill did the battery in water bottle thing already. Check it out here

- Adrian

 

[Kepler]

Thanks Adrian. I will do something similar 8)

 

[Kepler]

Got the parts back from the anodizer's last night and re assembled the drive. Here are a few shots of the finished product. I will post up some pictures of the drive fitted to the bike tomorrow.

 

[adrian_sm]

That looks awesome. How much are you charging for these again :lol:

Just a question, why the wire tether rather than a deadstop? I thought it could have been neater, and more easily adjustable.

- Adrian