Ken Taylor said:
Where is there a machine shop in Bali? I've been looking for one to manufacture drop outs, bottom bracket tubes and ream head tubes for the wooden frames I'm building there. A lot of people have told me the nearest machine shop is in Surabaya.
Answer:
C.V. Dharma Putra Benkel Reparasi Mesin Jln. Setia Budi 79 Denpasar (0361)426673.
They're real artisans. Following up on my munched plastic gear replacement/improvement idea, I responded to the shop's call to come get the goods they'd created:
Spittin' images in hefty shiny brass. Sans bearings. They'd forgotten that I'd specified bearings to match. That was
good because since my drop-off/order I'd gone back to Kepler's tear-down posts (p. 33 and
34) and "groked" the freewheel function of that white second reduction gear.
Veteran machinist Made (say "Ma day") and I scratched our heads. A one-way bearing was new territory for him too, and he's obviously been in the machinist's game for a long time. I suggested tearing the old one apart. He smiled...and stayed past closing time to extract the freewheel/bearing assembly from the munched white #2 reduction gear just to see what it looked like by first removing some of the plastic on a lathe, then using a hydraulic press.
Looking at the inside it
looks like your garden variety roller bearing. The plastic must have been poured/molded around the hexagonal metal bit. It's obviously not intended to be removed, but it's kind of fun tearing stuff apart to see what makes it tick, (or what made it quit ticking). Like a mechanical autopsy.
Made was having fun after hours helping this crazy foreigner. On his lathe, and in short order he banged out a perfect shaft from of a piece of scrap hollow steel shaft to test the freewheel action. It's a mystery to me how that sucker freewheels, but it does.
So... the hex bit may be proprietary/made by Bafang. It's an amazingly cool piece of "gear" - literally.
So why pursue brass gears when GreenBikeKit.com has replacement white plastic #2 reduction gears for $15? Because I hate plastic. Especially in mechanical devices. Don't get me started re: the stock Ford V4 in the Saab with the "phenolic" balance shaft/water pump gear that blew out in the middle of nowhere on a cross-country trip. Long night replacing that &%^ with a steel one that never failed. That munched plastic bad idea hangs in the gallery of infamy along with a broken rod, a bent valve and another trashed plastic gear from an outboard.
And I guess that bull-in-a-china-shop style of riding has something to do with it.
But it looks like the hefty brass replicas will not get to be tested for lack of the hex bit, which I think may provide the freewheel function. The roller bearing itself might not be unique.
Any ideas on that anyone? Especially where on might source the freewheeling-only-one-way/shaft-grabbing-the-other bearing assembly pictured above (in the BB-xx it's hex shaped)? It doesn't necessarily
have to be hexagonal so long as it doesn't budge from the brass gear. It'd probably be press fitted in. Inside bearing diameter is 14 mm. Outside assembly dia. is not really an issue.
