NAHBS 2014 mid-drive build

Drum said:
One correction however, brazing (despite the name) uses BRONZE rod, not brass, as the filler material. Bronze is stronger and more corrosion resistant than brass.
Click to expand...

Hi Drum,
The terminology of brazing alloys is rather confusing. I used C-04 brazing rod from http://www.gasflux.com/brazing.html. It is an alloy of mostly copper and zinc with some other additions. They list it as "Bronze"
Technically, bronze is an alloy of copper and tin, and brass is a alloy of copper and zinc.... so, I've always called the brazing rod "brass" because of the composition, but others call it Bronze...
-Paul
 
That is a really tidy clean build! Awesome, well done!
I spotted the tandem eccentric used as a chain tension adjuster, I have some identical ones here I have just bought for the same purpose! Did you use a bottom bracket as the jack shaft?
 
Article corrections made.

As a student of primitive tech, I can verify that Bronze is Copper/Tin. The Latin name "Britannia" means the "place of Tin", and the only reason the Romans occupied a section of Britain was the tin mines. Even after the beginning of the "age of Iron" (AFTER the "bronze age") resulting in all swords and spearheads converting to hammered Iron, bronze remained very valuable for other tools due to its much lower casting temperature. It was preciously recycled at every opportunity. Copper was so common that nuggets could be found near the surface in places like Cyprus (from whence it gets its name), but tin was rare.
 
Hi Paul,
thanks for the info.
I still have packs of brazing rod bought 40 years ago (my grey hairs are multiplying when I realize that!), in good condition, that I still use occasionally.
Although they do have a bit of zinc in them there was more tin, so it is interesting to hear that there are alloys around with a higher percentage of zinc than tin.
There's always something new to learn..

I still enjoy brazing more than welding.. it is somehow more satisfying. Unfortunately I don't get many opportunities these days.
My next build after I finish my current project will be an electric trials bike, teenage sized, and I will probably be building the frame for that, so a bit more brazing coming up soon, I hope.

Nice build on the bike!

Regards,
Dave
 
Tench said:
That is a really tidy clean build! Awesome, well done!
I spotted the tandem eccentric used as a chain tension adjuster, I have some identical ones here I have just bought for the same purpose! Did you use a bottom bracket as the jack shaft?
Click to expand...
Thanks! I bored out the bb threads so I could press in bearings and run a standard keyed 5/8" shaft.
 
Hi Paul,
In one of the photos you are machining what appears to be the motor shaft, with the magnets exposed. If I am right, is there any problem with swarf sticking to the magnets?
I had assumed that it would be an issue to keep the magnets clean.
Thanks,
Dave R
 
Drum said:
Hi Paul,
In one of the photos you are machining what appears to be the motor shaft, with the magnets exposed. If I am right, is there any problem with swarf sticking to the magnets?
I had assumed that it would be an issue to keep the magnets clean.
Thanks,
Dave R
Click to expand...

Yup, that is rather embarassing. :oops: I totally forgot after I started turning down the shaft, and of course, all the chips stick to the magnets. I don't want to think about how much time I spent pulling the filings off using double-sided tape stuck to a screwdriver.
I think sleep deprivation was the most likely cause :wink:
 
A beautiful design and a well executed project. Very simple appearing yet still sophisticated and complex. I'm glad to see stuff like this. It's funny to me how negatively traditional cyclists still view the electric bike as something tacky, lame and embarrassing. This is definitely none of the above. Stuff like this will go a long way towards improving the breed in general.

So how about some more detail? It would be great to see this in cad form to better understand just how everything is working. Is it only a one off or is green pea bikes part of a bigger plan? What about using an open source business model like that of Local Motors, makers of the Rally Fighter kit car, to manufacture the product?

I'm looking forward to seeing more green peas!
 
wingtip said:
So how about some more detail? It would be great to see this in cad form to better understand just how everything is working. Is it only a one off or is green pea bikes part of a bigger plan? What about using an open source business model like that of Local Motors, makers of the Rally Fighter kit car, to manufacture the product?
I'm looking forward to seeing more green peas!
Click to expand...

Thanks Wingtip. A big part of going to NAHBS was to attempt to change perceptions of ebikes amongst hardcore cyclists. I would be stoked if I helped that effort.
The open source manufacturing is a really interesting idea. I had heard of Local Motors before, but I didn't realize how they operate. I'm not sure what the future holds for Green Pea, I'm trying to figure that out. I have a full time job, so it's hard to imaging having the time to take it to production myself, but maybe someone would be interested in just that... but there is a ton of work to do making it production ready.
Oh, and I'll try to post some CAD images soon.
 
Paul, you (well, your bike did) made the centerfold in the June Issue of Electric Bike Action Magazine!

I'm really glad I got to see it in person.

Congratulations!
 
You must log in or register to reply here.

Similar threads

L
Joe's E-bike build
2
Replies
48
Views
4,442
lightbulb010
L
R
    • Like
A critique of mid-drive riding recommendations (and hub drive criticisms)
Replies
15
Views
5,214
Bullfrog
B
U
First build questions: commuter road ebike (mid-mount)
Replies
9
Views
1,473
Robocog
R
BigEzy
Build & Review - Hi Power Cycles' 1200W (52V) Mid Drive Kit
Replies
5
Views
2,075
Fastest1
F
K
2 speed mid-drive build
2
Replies
37
Views
9,341
kfong
K
Back
Top