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Monday: 32F/ 0C all day. My new and longer bottom bracket [131mm] arrived today despite being ordered mid-afternoon on Sunday. It provided much more clearance for the crank from the octagon woodwork. My first deliberately skewed hole with a hole saw meant that the crank hit the 2x4. Whoops!
So I drilled a perpendicular hole instead. This proved that the friction wheel provided the perfect gear ratio to drive the dome. However, now I could not keep the 2x4 steady enough for a long slew. I'm still 35mm short of the correct hole-saw so will have to go shopping to make any further progress.
14 miles and one 35mm hole-saw later and I began making better progress. I chamfered the back of the 2x4 to let in the BB for even more crank clearance. An aluminium plate, bolted onto the chamfer, will lock the BB securely in place.
I now need to make a firm pivot to support the 2x4 close to the friction roller from the far side alone. It cannot overlap the front of the 2x4 [as previously planned] because the crank would strike it. Surprisingly little pressure on the 2x4 lever is required to ensure sufficient grip on the roller to drive the dome steadily.
14 miles and one 35mm hole-saw later and I began making better progress. I chamfered the back of the 2x4 to let in the BB for even more crank clearance. An aluminium plate, bolted onto the chamfer, will lock the BB securely in place.
I now need to make a firm pivot to support the 2x4 close to the friction roller from the far side alone. It cannot overlap the front of the 2x4 [as previously planned] because the crank would strike it. Surprisingly little pressure on the 2x4 lever is required to ensure sufficient grip on the roller to drive the dome steadily.
It's not a lot of fun working at 32F in semi darkness with a solidly overcast, leaden sky and short hours of what might, half jokingly, be called "daylight." Back and forth between the dome "upstairs" and the workshop at ground level. Up and down the cold, metal stepladder.
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