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.

Nailed It - Con Rods Part 1

After weeks of painting, plating and making things look pretty I've finally got back on the machine tools making swarf and thoroughly enjoying myself.

Isn't it pretty? Even my lovely wife think so. 

I caught her showing it off to some friends the other day.

The gear guard in place for the first time.

It took me several evenings to get it back together, I didn't rush it and only got the one deep gouge in the paint where I had to spring the forks to install the front wheel.

I seem to be rapidly running out of bits to make which is both good and bad. Good because the bike is nearly done and bad because the hardest bits are still to come. I'm going to make the connecting rods next. Everybody knows what a con rod is, it connects a piston to the crank shaft. Well so do these con rods if you think of your feet on the end of the levers as pistons and the crank as erm... the crank. Even though the ICE wasn't yet in wide use, it had been around for years and the term would have been familiar enough to the makers of the geared facile, Ellis & Co, to use it in their catalogs. But I digress.

This page is from the 1884 Ellis & Co. catalog from my own collection. 

Email me, using the link at the right, if you'd like a complete scanned copy.

Ellis and Co. have used at least two styles of con rods on the geared faciles. Early ones such as the Percy Nix machine in the Coventry museum has tubular arms, later ones are solid and much more slender in section. I'm going to be making the later style.

The Percy Nix machine from 1888 (second year of production) has the earlier, tubular style of con rods.

The later style are solid and much more slender.

You can see from the photo above that three of the ends are identical (apart from oiler placement) which means I can make all three at the same time. If I had access to a big lathe, I'd simply make each con rod from a single piece of stock and bore each end at a time. The centres on the con rods are 8.5" and I would need a fairly hefty lathe to swing that, even in the gap. I don't have access to such a machine so I'll do it in sections on my trusty little Myford and then join them up. The right hand con rod will be made in three sections, both the ends and a centre section. The left hand con rod will be made in two parts since the top end doesn't need to be turned. I'm having a dilemma about how to successfully join the sections. I could ask Pete the Welding Ninja to TIG them up for me or I could silver solder them with a lap joint. The difficulty comes from the need to harden the bearing surfaces. I'm going to have to think about this. As usual, here's a stack of photos.

Calculate the minimum size of bar stock required and mill a flat on each side.

Then saw it into the three pieces and mark out the shape of the end.

I'm going to bore the holes and bearing surfaces in a four jaw so I need to remove as much material as possible from the stub to prevent vibration when running off centre at speed.

Mill the sides so that the stub is at the correct width. 

Roughly file the fillet from the stub to the body and mill the corners off 
so that the shape can be held securely in the four jaw.

Repeat with the front and back. 

I've left enough material to produce a nice fillet between the end and the shaft.

I've needed to make a parallel spacer out of some scrap tube

 to ensure that the work sits square in the four jaw 

Centre on the marked punch and drill and bore the central hole 

Also clean up the outer face. I can't profile the outer edge at this time as I need

 the flat surface to align square against the parallel spacer when it's turned around.

Rough out the shape of the bearing surface at a 45 degree angle...

...and use the profile tool to machine the bearing. Then polish the surface.

Then flip over, re-centre on the bore and repeat.

Next mount on a mandrel...

...and machine the edge profiles.

Then mount on the mill and clean off all the 'corners'. I would like to use a rotary table 

for this but I haven't got one so I use my dividing head instead.

Finally give them a little tickle with a file. I'll wait until I have the centre section made 

before I profile the stub that attaches to it. As I said I need to have a think about it first.

In other news, I did a most stupid thing this weekend. When Pete (hired muscle) came and Kung Fu'd up the old deck, we just threw the wood into a heap behind the facile factory. I'd been meaning to do something about it ever since but my lovely wife forced my hand this weekend and made me do it. The old deck boards had many rusty old nails sticking out at all sorts of dangerous angles. I laid the boards down and knocked the nails flat with a hammer before sawing the timber up for our wood burner this winter. The timber is untreated hardwood so useful as fuel. I thought I'd got all the nails done and went inside briefly to answer the phone. Afterwards I ran down the back door steps and put my full body weight on the one remaining nail that I'd missed. It pierced the sole of my shoe and then carried on through my foot and came out the top. Of course the nail was a special deck nail with annular grooves that made it hard to get out. I had to put my other foot on the board and yank my crucified foot off the nail. Being male, I naturally didn't go to the doctor until it had got properly infected and had gone an interesting colour. I thought I'd had a tetanus when I had my spectacular crash two years ago but apparently not, my last recorded one being in 1993. Probably best that I don't put a photo of my foot up I think. It does mean that I'm having to soft pedal with my right foot and standing on the pedals is out of the question.

An annular grooved nail, yesterday.

Planetary Alignment

Syzygy, get that one on a triple word score and I reckon you'd clean up. But I digress.

So this shedweek I've been back on the tools again. With my repaired mill working properly again I've been able to make a start on the left hand crank arm. This arm also doubles as the planet gear carrier that holds the planet in constant mesh with the sun. It is a complex part in that it has three bearing surfaces, two of which are concentric and the third has to be very accurately positioned relative to the first two. This bearing spacing is what determines the gear centres and must be carefully measured.

The left crank arm / plant gear carrier from the original geared facile.

Roughly half of the originals I have seen have this face slightly hollowed out.

This one doesn't, it has the patent information stamped on it instead.

We know from previously that my gears run on theoretical centres of 2.977". I wanted to check this empirically before spending hours making a component that doesn't fit. I contrived a set up in the lathe where I drove the sun gear in the chuck and was able to feed the planet gear in and out of mesh on the cross slide. It turns out that my gears are happiest at centres of 2.970", only a 7 thou difference but I'm a pedant (no, really?) The nitriding process will very slightly increase the size of the gears, but this will not be measurable with my equipment. Also recall that involute gears can cope well with incorrectly spaced centres but I'd much rather make the centres too wide than too tight. The original facile I rode had very sloppy gears and it was unnoticeable when riding.

The sun is driving the planet. Of course in use, the planet will drive the sun.

As before the crank arm will be made from 4140 and nitrided, the most economical way to get 4140 of the right thickness is to start with round bar. A little trig to calculate the minimum size that contains the shape and then get busy on the mill.

Mill a flat on one side of the appropriate depth. In this case 0.375" which happens to be...

...the thickness of an old bearing. Bearings make excellent parallel spacers so I can flip 

it over and machine the opposite side and ensure both faces are parallel.

Now we have to apply a little thought about how to get those two holes accurately centred. Clearly, two centre punch marks aren't going to be accurate enough, the quickest and easiest way is to use the dials on the mill and the mill as a drill. First part is to saw off the work and remount directly on the mill bed such that it is parallel to the ways, in this case the y-axis. A dial gauge is invaluable here. Then using an edge finder, we can determine the centre of the work and lock the y-axis. Any hole then drilled along the x-axis will be on the centre line. Next use the edge finder to calculate the x position of the first hole on one of the bosses. Lock the x-axis and centre drill that hole. Then simply move the bed 2.977" using the x-axis dial, lock and centre drill the second hole.

Holes at 2.977" centres (reasonably accurately)

Then we have to remount on the faceplate for the next operation. Use a live centre to hold the work centred on the planet boss and clamp (very) firmly. Anything mounted this eccentrically is going to cause serious vibrations when run at any speed so it is crucial to balance the faceplate. In Sparey's book, he features lots of pictures of change gears used as counterbalances. I don't like doing this, change gears are expensive and should be treated with a little more respect whereas lumps of scrap metal with holes are plentiful and cheap. I have a cunning little tool that helps enormously with balancing faceplate setups, I simply turn the tail stock around and mount it in the Morse taper and hang the faceplate off the end of the lathe, it spins freely and will always hang heaviest part down. By playing around with counterweights and sliding them in or out, it is possible to balance even the most awful set-ups.

A balanced set-up.

Using a live centre as a steady, and periodically checking for deflection with a dial gauge directly onto the live centre, it is now possible to machine the boss. Small feeds are needed as this is an interrupted cut and any hard blows will knock the work off centre. Not what we want.

The planet gear boss at final size.

On all of the faceplate set-ups, I periodically check for movement of the centre with a dial gauge.

Now I can make a faceplate clamp just to suit this boss, to hold the work very tightly 

so I can bore the hole and the inner bearing surface for the planet gear.

Then flip it over, re centre and machine the outer bearing surface.

Stuff the outer bearing full of balls and check for fit with the adjuster in place.

Next remount (again) and machine the live axle boss and bearing surface into the other end. 

Also tap the boss for the live axle (5/8" cycle thread).  I didn't need to make a special clamp for this end as the other end has a through hole by now which made the set-up more secure than before. These faceplate set-ups were very quick to machine but took much longer to align. The difficulty is that as you start to bolt things down to the faceplate, you get movement, not much but enough to throw the work off centre or out of alignment. My dial gauge is very sensitive at 10,000 of an inch increments and it make the adjustments easier. you have to go through a cycle of tighten, check, adjust, re tighten etc. until everything was exactly in the right place and tightly bolted up

All the machining is now complete. I just needed to 

clean up the faces with a file ready to mark out the profile. 

A few minutes with a hacksaw and then a little longer with a file.

I still need to drill and tap for the oiler and the patent information needs to be stamped into the outer face, but I need excellent light for this so I'll do it outside at the weekend. Also the tapered holes to lock the arm to the axle still need to be figured out. More later.

Next week, I'll make the live axle which is trivial and then tackle the planet gear, how exciting is that?


In other news, the bridge over the Ashley river reopened for a nanosecond allowing me to get a ride in on my favoured route. We had a full day of heavy rain yesterday so it is now shut again. Sigh. A work colleague suggested that the current state of affairs is no different to having a ford instead of the broken bridge. When the river is low, you can drive over and when it is high you can't. It would be a lot cheaper.

Also, the Old Waimakariri Bridge is now also shut for unknown reasons since the river is very low. I'm not sure if cyclists are allowed over it. If not I'll be forced to ride down the motorway which is Not Fun. Honestly, the infrastructure around here is pants, none of it is even earthquake damage.