Tuesday, 18 February 2014

The Trampoline Road Trip

As I mentioned last time, our family has other stuff going on at present. Even so, I was surprised that I haven't posted for so long. I'll try to remedy that in future. My apologies.

So this past few shedweeks I've been sneaking in a little time to make all of the components for the pivots, there are five of them, two pairs and one odd one. They are all more or less the same size although some have flats and some have slots but broadly speaking they are all the same.

I thought that given that most of the work is simple turning I'd be able to knock them out quite quickly. As always things progressed slower than expected.

The pivots themselves are turned between centres so that I can do the same operation on all five at once before moving onto the next machining job. The photos are therefore not necessarily of the same pivot.

 The first job is to rough out the bearing surface...

...before polishing...

...and checking for size.

Next thin the shaft and cut the thread on the end.

Flip it around and machine the other end to size and cut the second thread. 
Note that the driving dog is an old wingnut. I like cycle threads, I may have mentioned this before.

Some of the pivots have flats...

...and some have slots.

The next job is to make the cones that make the other end of the bearing. These can't be turned between centres, so starting with a suitably long piece of bar stock

Rough out and polish the bearing surface, then drill and tap the centre (not pictured). Part off.

Next make an arbor to hold these parted off cones to machine the recess into the obverse. 

This will ensure that it remains concentric with the thread.

The last job on the cones is to slit through the recess so that it can be adjusted by a tool I haven't made yet.

The washers turned out to be tricky little blighters and I had two attempts before I was happy.

First job is to mark out and very carefully file out the holes to be a tight fit on each of the pivots. 
I bought some hugely expensive needle files just for this. I like filing, I may possibly have mentioned that before.

Next chop out and mount on a suitable arbor between centres so that they can all be turned down to size in one go.

The last parts are the nuts, there are 5 smaller locking nuts for the bearing cones and 5 larger nuts to secure the pivots to the various bits of lever, crank or frame. They are both the same design and the machining operations were identical for both. I had enough scrap steel for the smaller ones but I needed to do a raid on Kung Fu Pete's scrap bin for the larger 3/8" gauge plate.

The first job is to drill and tap the holes.

Then using the same technique as for the washer, chop out and mount on a mandrel.

Turn down to size and then...

...use the dividing head to slit both sides at 180 degrees. These nuts also require a tool that I haven't made yet

The one on the left is the odd one out and the only bearing that fully rotates at the top of the right hand con rod. 
The next two short ones are the two at the bottom of each con rod, these only oscillate. The longer two on the right are also slightly larger in diameter and are for the lever pivots, they also only oscillate.

Those bits requiring hardening have been taken in today. I should get them back tomorrow. then I can plate and paint as appropriate.

Hey guess what? I've only got the levers left to make. Hoorah.

In other news, Kung Fu Pete suggested a road trip last weekend. He'd bought his kids a trampoline on TradeMe (domestic version of Ebay) and it was pick up only from Methven. We got busy planning the route to collect as many new old velodromes as possible. Google Maps on satellite view is the primary tool but care must be used in this part of the world as horse racing and training is big business around here. Almost all old genuine velodromes are located in reserves or domains, public land in other words. Canterbury has a rich cycling past and most towns of any size at some point from the 1880's on took the trouble to build a local velodrome. We have to do an actual field visit to walk the site and physically verify the track. We then need to find historical documentation to back this up. The website papers past is extremely useful here, as we can often find newspaper reports of race meets. We've also found that a quick visit to the local settlers museums can yield local photographs and often staff either remember details themselves or can point us at people still alive that can. It's a harmless hobby and I've been doing it for years now, initially in England but now in NZ where the density is much greater and the pickings are much richer.

So this trip we collected Oxford, Pearson Park. Then a slight detour to go and visit the Secret Steam Railway Locomotive Graveyard. I hadn't been for a few years and it took some scrambling through bush to get there. I scored a deep scratch on my knee that I later told my kids was caused by a rare NZ bear. It's a long story.

I can't remember if there are 11 or 14 dead steam engines visible here. 

When they had reached the end of their useful life they were towed to where the lines crossed rivers that were causing erosion to the railway embankments. They were jacked up and toppled into the water to help prevent this. Amazing eh?

Then back on route to collect Springfield. Kowai Pass Reserve. An unusual shape but still very visible on the ground and has documented bicycle race history. Whilst in the area we both simultaneously spotted a 1930's Jones Special under a tree, It had full BSA kit including a cam rear hub and a Major Taylor stem. The owner wouldn't sell it but I haven't given up yet.

Then onto Glentunnel where we knew cycle racing took place in the 1890's but not where. Nothing visible in the domain but the museum was open so we popped in and were shown a photo from the right era of the local club. The curator told us that racing took place around the pond above 11a Railway Terrace. The pond froze in winter and provided an ice rink and then dried up in summer and provided the velodrome. The same man promised to look into the Springfield track for us.

Onto Methven to collect the trampoline and then down to Tinwald to collect the double velodromes (It's a sign, what can it mean?). When the new one was built there was debate over whether to build it in a new spot or over the top of the original. The original has people camping on it at present, I wonder if they know what it was.

Then up to Rakaia, the domain took some finding but has the most pristine example we've found yet, It was beautiful. Then over the river where we decided to leave Southbridge for another time. A quick dash up Telegraph road to Kirwee to check out the domain there. Telegraph road now has a distinct kink in it due to the recent rupturing of the Greendale Fault that has caused us all so much trouble. The road moved by half the width of the road. There was nothing to see in Kirwee so we just drove back from there. my lovely wife having only signed my pass for the afternoon.

We already have another road trip planned in the near future to collect a few more examples. We've now found that looking for documentation from old newspapers and then trying to locate the tracks is a better approach, we now have at least another 5 to tick off. It seems that cycle track racing was an enormously popular sport here in the outer colonies even as early as the 1880s. The density of tracks being built during this period is incredible. These tracks attracted the top stars from around the world. More later as we find it.

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