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I was going tweet but couldn't convey the mesage in 140 characters.

I hope my voluminous post gives a sense of the trials and tribulations in this endeavour :-)

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Yet another update! We've put some serious hours in this week, building the clock in Birmingham (Millennium Point - access is free if you are anywhere near but read on to understand what you might

Another busy day but the end is in sight now. In fact I've left it running as a 'soak test' (albeit still a dry installation - they are planning to fill the pool tomorrow). I've overcome a few minor

Nope, not TT. On the matter of drinking, each day I've worked within that enclosure has been physically exhausting because of the heat and humidity - somewhere between a greenhouse and a sauna. Have

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Brilliant! Any chance of a few photos?

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WOW - I had forgotten how good it looked when new and shiny!

Great job by all involved!

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Great work there Pete. Definitly a labour of love but worth it in the end, be good to see it in its final resting place back at the Vic center.

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In that last photo, it's me up the step ladder (I'm terminating the bell). That was late in the evening last Wednesday - the bell was the last thing I wired before applying mains.

I'm heading back to Brum on the morrow to do some snagging.

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Looking ahead to next year, I spent some time over the weekend drafting a design for the pumps, filters and pipework that will be needed when the clock is back in Vic Centre and passed this to the architects.

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Titter ye not!

Now then, I have a query - I think we need a new drive pulley for the top mobile thing with three arms. The pulley fits on a bicycle bottom bracket, the old type that is designed to fit cranks with cotter pins. If I can buy a new pulley, i think it will need boring out to fit but I don't know the diameter of the shaft where the crank goes on. Maybe a trip to a bike shop with my caliper will answer this.

Eng

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Sorry engineer but you do make me titter,good luck with the 'cranks and cotter pins' :)

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Took some finding but it seems that the diameter of the ends of the bottom bracket axle should be 15.86mm +0.00mm, -0.15mm (that's about 5/8"). A likely source for a 4" rubber-faced cast iron wheel is Reids of Nottingham, Miall Street, Radford so I shall enquire there.

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  • 2 weeks later...

Not posted for a while as have been busy trying to fix a clock.................

Now then, where was I ...... we covered the three day move/install (2/3/4-Jun) and that ended with a poorly clock in many respects. So, next visit was the following week:

TUESDAY 10-JUNE

Petal drive - the vee belt was too long and the mechanism too tight (stiffness from overspray on bearing surfaces). As a temporary fix, I fitted the vee belt inside out. At worse it would damage the belt but it seemed to work for now and overcame the stiffness in the mechanism. It was also apparent that the "throw" of the crank was too great (it was trying to move the petals past their mechanical limits). The throw is adjustable so I adjusted it.

Cobweb Wheel drive - I trimmed 1/4" off the end of the shaft as it was too long and catching the wheel occasionally. I took a lead counterweight off the swinging arm that puts pressure on the drive pulley and fitted a steel weight on instead. The wheel seemed to speed up and slow down - it was out of balance so I screwed the recovered lead weight to one of the water catchers. The wheel now ran quite smoothly. The back panel for the control box (where the wheel drive shaft exits) was tight on its fixing screws so I filed the holes out a little to ease that.

Orchestra drive - I thought it was an electrical issue at first so I tried a replacement capacitor. The motor then ran (though the orchestra turntable didn't budge). It became clear that it needed more pressure on the drive pulley so I tensioned the spring as far as it would go. The turntable was just about driving. I reconnnected the original capacitor and it still worked (the problem had been the tension).

Top Feature (the three-armed mobile) - I adjusted a collar on the drive shaft so that the weight of the shaft was not bearing down on the gearbox - needed doing it didn't improve the drive. With access from a portable tower scaffold, Ed fitted rubber bands over the turntable drive pulley. The Top Feature moved - for a few minutes - the bands came off. Ed then fitted a couple of charity wrist bands. It worked for a while longer but failed again.

So, this day ended with the presumption that there two remaining problems - the Top Feature was not driving and one of the clock faces was out of sync with the other three (we hadn't looked at that today). We knew we needed the Spider Hoist again to look at these parts. However, we were told that the Spider had a hydraulic leak and would be serviced the following Monday (16th). The next time that Tim and I were free would be Thursday 19-June so we planned a visit for that day.

Engineer

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THURSDAY 19-JUNE

I arrived on site at 0945hrs. The Spider was fixed so up we went (one of the MP technicians and I). The dodgy face was the rear one (we've decided that the Cobweb Wheel is the front of the machine). I re-synchronized all four faces to 12:00.

We moved down to the Top Feature turntable. My intention was to put a section of inner tube over the pulley (the pulley is a rubber-faced Flexello wheel that is probably the original: 40+ year old rubber is understandably a bit hard). However it proved not possible to stretch the inner tube enough to fit in-situ (there is limited access up there). Instead we found some synthetic rubber strip, about 3/16" thick and after a debate on types of adhesive, decided to glue it on to the pulley with quick-set epoxy resin. Impact adhesive may have been better suited (more flexible) but it was not practicable to position the strip correctly at first attempt (you only get one go with Evo). What a messy job - limited access, epoxy all over my hands, trying not to spread it to other parts, etc. I popped a couple of elastic bands over the strip to hold it in place for the 10-15 mins cure time. I powered up the motor and the Top Feature seemed to run OK, although the start-up seemed sluggish.

I powered the whole clock off while I reconnected the drive to the clock faces. However, while advancing the time, it was clear that the rear face was still not right - the hour hand wasn't keeping up. We accessed the clock faces again from the Spider and on inspection, I found that the hour-hand reduction gears were loose on that face (gears for the other three faces were fine). It is two gears on the same shaft that should be fixed together (pinned or soldered I guess). I decided that it couldn't be fixed readily and we agreed to leave that to be remedied before re-installation at Nottingham next year.

I powered up and the Top Feature did not start up. We gave it a push or three and it started rotating. I wasn't confident that it would sustain another stop/start cycle so I overrode the night switch (in normal operation the night switch inhibits Cobweb Wheel, Top Feature, Orchestra, music and bell at night). This would mean that the Top Feature should run continuously.

As we had three clock faces able to move together, I synchronised the clocks to the chiming mechanism and advanced it all to the correct time.

Meanwhile, Tim had been wiring six LED spot lamps together with a couple of junction boxes and lengths of flex. I connected this into the electrical control panel.

We tidied up and Tim took a few photographs. It looked promising. We watched the 1630hrs performance and all was well.

Just as we were leaving I turned for a last look and ................................. the Top Feature had stopped rotating! To say the least that was frustrating. I pulled its fuse and we departed to gather thoughts and decide what Plan C should be.

Engineer.

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Before I continue with the update on the work at Millennium Point, just need to say that I've been contacted by Intu's design consultants about the water works and the power requirements for re-installation in Vic Centre.

Appears there would be a problem with having the electrical control box in the nearby corridor as the route for cables would have to pass through an occupied shop on the ground floor (they don't want to do that). I said the panel doesn't need to be remote (just that it was remote before). In fact I'd prefer the panel near the clock as it would make maintenance easier. We'd already concluded that we need an enclosure by the clock for the water works (pumps/filters/valves) so they suggested a second enclosure, on the opposite side of the clock. Initially I said OK but could the electrics be north and the water be south (the Cobweb Wheel end). On reflection, I later said an enclosure in front of the Cobweb Wheel may detract from the aesthetics so could we have just one enclosure at the north for everything (water bits, electrical control panel and audio system). I did a 3D drawing to show how it would fit in a box about 1000mm wide, 550mm deep and 550mm high (with raked top). They are considering my proposal.

Just to clarify, north is towards the bus station. I've already said I think the cobweb wheel should face south.

Engineer

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Thanks for the updates. It is fascinating reading about it all. The clock looks fabulous in the photos, and your problem solving skills are second to none. I have every faith that you will soon have it up and running. thumbsup

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And so to this week...........

THURSDAY 26-JUN

Had been at work in the morning so got to MP around 1430hrs. Wasn't expecting Spider + driver until 1530hrs so had a look around the clock. I then saw that the shims I had used on the Cobweb Wheel bearings were coming out and one or two were completely out (still captive on the shaft). I took the outer bearing and its shims off. They were smothered in oil - must have oozed out of the Oilite bearing as we hadn't added extra lube. I cleaned the shims then glued them together to make one solid mass. I tried to refit the bearing + shim but it was tight (the film of glue must have added to the diameter). I tried tapping with a hammer (and a wooden spacer of course) but it wasn't having it. The Spider + driver turned up as did Tim. I asked Tim to give me a lift to take the wheel off the clock and lay it down. The shims for the inner bearing fell out as well. The Spider was only available for two hours so I donned a harness and abandoned the wheel for now.

I accessed the Top Feature drive (that rubber-faced pulley to which I had glued a strip). The strip was still there but obviously slipping (the pulley drives against a steel turntable). I had decided that the only way to go was to remove the pulley assembly (wheel + swivel arm with cycle bottom bracket). It was only held by a split pin but access was limited. Anyway, I got it off. I ripped the synthetic rubber strip off, cleaned up the wheel and managed to get a section of inner tube over it (I had help). Refitting was a bit fiddly - slide arm onto a swivel pin at the same time as holding a plunger against a spring and locating the drive shaft below - needed three hands and only had two. Eventually it slipped into place. Stood back and switched on - it started up slowly and then ground to a halt. We went up in the Spider again and I sprayed it with belt dressing (it supposedly helps with grip) - no better.

I took the assembly off again and away to a bench with a vice. Between three of us we managed to fold the first section of inner tube back on itself to double the thickness and then get a second piece over it. I glued the edges down with spray-on Evostick (other brands of impact adhesive are available). Back to the Spider, repeat the struggle to fit it, down, out, stand back, switch on and ........ it worked. Now don't switch it off again!

Back to the Cobweb Wheel: hammer + timber + solid floor and I got both bearings back in. Tim and I offered the wheel back onto its shaft - it went on but had one or two tight spots - not good. Tried engaging its drive and the rubber pulley just slipped. the outer bearing had been the tighter of the two so I suspected some deformity had crept in. I used an engineering technique to find the high spots on bearing and shaft and worked at these with some fine emery tape. The fit improved and though I wasn't entirely happy with it, the drive seemed to turn it adequately. A couple of flowers dropped off so I refitted them (must have vibrated loose). Left the wheel running and turned attention to the Orchestra turntable, which had been getting sluggish and would sometimes stop when it shouldn't.

There were some step ladders nearby so I accessed the Sunflower and removed a section of orchestra floor. First I sprayed the rubber drive pulley with that there belt dressing stuff - no good. Next I decided that the tensioning spring could be shortened a little so did that. The drive between the motor's pulley and the turntable seemed better but again it stopped at one point. The drive pulley was similar to the one we had been working on for the Top Feature. However, this one was 5" compared with the other one being 4" so there was no way we would be able to stretch inner tube over that. I had a length of synthetic rubber belting around 2mm thick and 60mm wide so I decided to glue a strip of that over the pulley. To facilitate this I had to remove the motor assembly from the Sunflower (not too difficult except I was at full reach leaning over the copper petals, which were a bit sharp - I gashed my jeans so they had to go in the bin when I got home). I glued two layers of belt over the wheel and refitted it. The Orchestra rotated as it should - no hesitation.

It was now around 8:30pm. We were about to leave when the doorknob fell off the wheel (for some reason Rowland decided that there should be a doorknob fixed to the rim of the wheel). I fixed that back on and we left.

to be continued...

Engineer

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FRIDAY 27-JUN

Tim sent me a text to say that he had called by and the wheel had stopped. He said he nudged it and it started up again. I didn't like the sound of this because it might mean that the geared motor is getting stressed if the wheel is still too tight (and that was the brand new motor that cost around £300+VAT). I said I'd visit again a.s.a.p. to ease the wheel.

Engineer

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I'm assuming it's bearings are sleeve??? If so, isn't there a way of adding sealed ball bearings???

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Originally there was a fixed shaft and the wheel had two flanged bronze bushes. At some point in the clock's history, it was modified (were I to be unkind I'd say butchered) to fit two ball bearings in plummer blocks behind the wheel. That was obviously done without careful consideration of the load and moments about the axis. The shaft, the bushes and the wheel were all pinned together and rotated as one. The ball bearings were too close together and ultimately failed on more than one occasion due to excessive lateral loading.

I proposed that during restoration we revert to the original configuration. This wasn't simple because we had to reinstate with careful alignment several steel tubes that had been cut away. The original shaft and bearings were damaged so we procured a new shaft (imperial size 1-1/4" diameter) and imperial flanged sintered bronze bearings(AJ2026-20). For slow moving parts (the wheel speed is 6.4RPM) this is a good choice.

Engineer

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TODAY - SATURDAY 28-JUN

I visited Brum this morning. The wheel was rotating but the rubber tyre on the drive shaft had a groove in it about 4mm deep where it had been turning against a stopped or slow moving wheel.

I spent as long as it took to lap the bearings and shaft to a point where I could turn the wheel with one hand gripping the central hub. I fitted a new rubber tyre.

To press the rubber tyre against the drive hub on the wheel I had devised a swinging arm with a counterweight. I was now able to shift the counterweight to reduce the pressure to a minimum, which should increase the life of the rubber tyre.

After Thursday's incidents of bit falling off the wheel, I systematically removed each flower and butterfly bearing block (and the door knob) and applied threadlock to the screws be fore refitting.

Well I think I'm done for now. Do let me know if you go to see it at Millennium Point.

Engineer

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  • 3 weeks later...

Got a message today to say the animals aren't spinning when the should. I guess this means the orchestra players. I'll arrange to visit Birmingham within a few days to look at this (though looking ain't gonna fix it - must take spanners and a meter).

Engineer.

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Visited the clock this morning. Cobweb Wheel and Top Feature both running normally. At 08:45, the bell struck, the petals dropped and the music started. However, the Orchestra didn't budge, though I could hear the motor running. I borrowed some step ladders to get up close and remove some covers. As I had now surmised, the two lengths of belt that I had glued to the drive pulley (26-Jun) were lying loose, having somehow come adrift. I removed the geared motor assembly.

I still had the rest of the inner tube that I had previously used to enhance the drive for the Top Feature but there was no way I could stretch it enough to fit over the five inch Orchestra pulley (it had been a job and half to get it over the Top Feature's four inch pulley). However, I experimented by cutting diagonally to create a band that was "S" shaped when laid flat. I was able to stretch this over the pulley. It didn't lie quite flat but I decided to go with it and cut another similar strip to fit over the first one. I refitted the motor and it ran OK so I left it like that. Let's hope it lasts until we next dismantle the clock.

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