Saturday, September 23, 2017

Tallbike seat stays etc.

Decided to preserve Healing seat stays because = simpler. First I took my Tarini frame and snipped off the seat stays and lengthened them to accommodate a 700c wheel, being too lazy to weld on cantilever bosses. The lengthening was easy, ugly and may need reinforcing if for no other reason than to pretend there isn't a stress concentration which there probably isn't because when you ram a tapered thickened seat stay backwards into another one and weld them together, there's an awful lot of thick and heavy steel sitting there.

Back to the original plan, and extending the bottom tube for the ostensible reason of creating a rear luggage rack. And preserving the faux seat tube for the front derailleur  mech. And snipping some seat stays off a few other bikes to see what would fit. Burning off the paint. Wire-brushing the ash. Pretending the ash molecules aren't pollutants and won't have any effect on the garden or on my unprotected lungs.

On to drilling 4mm holes for plug-welding, and since I can no longer get the machine onto the drill table, doing so by hand with the inevitable blood sacrifice.

Don't feel sorry for cut, feel sorry for stupid.

Since back-of-knuckle wounds aren't self-sealing, into the bathroom for plaster, knock mirror off shelf, into kitchen for dustpan-and-brush, mirror-shards wrapped and binned, plaster on, resume welding. As I say, don't feel sorry except for stupid.

Lots of shaping, lots of extra bits of tube, lots of weight. Did I really hope it was going to end up a lightweight? No, I didn't. And a bit more Googling reveals that one was right to be concerned about that elongated fork steerer tube. I found someone else who built one, and it cracked exactly where anticipated.

Gnarly seat stays to match gnarly chainstays

Methinks that parallelogram may need diagonalising.

My neighbour was impressed. Actually he was more impressed with Ron's bike which had luckily remained untouched, and since all it needed was air in the tyres I pumped them up and gave it to him, and he rode it down to the wharf this afternoon and came back puffed.

On to contemplate cabling, a job I hate. Couldn't get the cable to come from underneath the front mech cos there's that horizontal in the way. Why didn't I think of that before? Because I'm stupid, that's why. I needed a curly channel thingy to get the cable to curve round smoothly. Ideally this would have a 72mm diameter curve but one of those wasn't to hand, so I filed a groove in a snipping of Grotesquely Heavy Headtube from some other discarded bike.

Rubbish photo cos camera's gone All Funny. 

Sudden awareness that those seat stay cantilever stubs are too far apart. Squidging a Vee-brake at the top will impart more of a diagonal than a horizontal motion to the brake pads. Why didn't I think of that before? See above; stupid's why. They're four and a half inches apart. Need to be three.

Camera's still funny

Chopped a front fork in half to extract the cantilever stubs, and welded the entire fork section in place, using the altogether better idea of nipping the brake pads onto the rim while welding.

Must google Canon Powershot A430 and find out why it's misbehaving. The trouble when you inherit your electronick devices from your children

A bit ugly, but who'll be looking at this partic'lar bit of ugliness when there's so much more?

And on to making cable joiners. An intelligent person would simply go to the bike shop and buy tandem cables, but an intelligent person wouldn't be building this machine. Anyway buying stuff defeats the repurposing purpose. Besides, it's quicker to make a joiner than to cycle to the shop and home again, esp. if someone's thrown a bottle onto the bridge, which they have, and you have to go home and get a broom, which you do, because the Council won't come out for a month, which they won't.

Two bits of 1.6mm mild steel. Folds introduced with hammer and vice. 3mm screws 21mm apart.Gap at side 2mm to allow two 1mm gear cables to enter above one screw, cross the middle, and exit below other screw.

Tomorrow's task can be to weld cable stops on and get the back brake to work. And to fix the camera.

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June 15, 2018 at 9:03 PM  

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