The Abingdon Ball Head - part 2

Spring has sprung, the grass has riz.
I wonder where the birdies is?

etc.

In stark contrast to last week, Spring appears to have been switched on at last. The birdies in the above poem (incidentally not by Spike Milligan as I always thought) being magpies. We are nearly in the attack season again, I know this because I had one shout at me last weekend, next weekend he will be dive bombing me. But I digress.

This week I have made the top lock nut for the ball head, I have chosen to make the flush variant as I won't be using a lamp bracket mounted on the head. The original I am copying does have a lamp bracket as did the Percy Nix machine in the Coventry museum. This machine was used for the 24 hour race and would certainly have required a lamp for the night time part of the event.

This is a photo of the bike taken in or prior to 1931 (when it was in the Sammy Bartleet collection) 

and the lamp bracket is clearly visible. From Bartleet's Bicycle Book, 1931

The bracket has now disappeared as in this photograph I took just a few months ago of the same machine.

But this is what the flush variant looks like, neat eh? 

The Upper example is an early geared facile and the lower is a non geared model, both by Ellis & Co.

Machining the lock nut just involved simple turning and screw cutting 

plus a little indexing to get the holes in the correct place.

Now I can mount the completed neck into the head itself and establish

a) the length of the backbone to provide the correct inclination of the forks, this effects the trail of the machine and consequently how it handles.

b) the correct angle of the backbone to maintain an even gap between the wheel and the backbone. Although saying this, I have seen backbones on originals all over the place, some are very closely fitted with an even gap and some are not. Of the various originals I have now seen and measured, I have yet to see two the same, a remark echoed by other collectors that own these machines.

The angle of the forks likewise seems to vary hugely, the very early machines are more upright, something that is clear in the advertisements and literature. I've measured several from 1887 that have as little as 5 degrees inclination on the forks. This is in contrast with younger bikes that have up to 16 degrees inclination. The anomaly here is the racer from 1888 that has a full 20 degrees, this would produce a high trail value (for the period) that would be more stable at higher speeds with more rider fatigue. This is just my theory at present, I suspect it could probably be able to be ridden hands off.

As an aside I am currently reading the excellent new book on Dan Albone and Ivel cycles by Ray Miller and Lee Irvine (ISBN 978-0-9566337-4-3 available from the VCC UK). In chapter 5 Ray discusses how in 1886, Albone invented the first rear driving safety that could be ridden hands off, the discussion mentions the steering geometry being responsible but no actual mention of the trail. A friend of mine owns an 1887 Ivel safety locally (it is photographed in the book). Next time I see it, I'll measure the trail and report back. Clearly, steering geometry was beginning to be understood a little more by this time and I see no reason why Ellis & Co. wouldn't have adopted the current thinking at the time to slacken the head angle to provide more trail. I have decided to use an inclination of 16 degrees (the same as the original I am copying) which will give a moderate amount of trail.

The next job is to file the stub on the neck casting to be a very accurate fit into the backbone. I have made a little jig from part of the off cut backbone, this jig is coated with engineers blue, an evil substance that will coat everything within a 100 metre radius if children and cats are allowed into the workshop at the same time as the tube is open. The idea is that the backbone is placed into the jig and the high spots are marked by the blue, these high spots are then filed off and the process repeated. Great care being taken not to twist the casting relative to the jig. This took many hours, but the care has paid off and I now have a very well fitting backbone that should braze easily.

The jig to mark the high spots on the casting, 

shortly before engineers blue covered everything.

File off the marked high spots and repeat. Carefully.

Eventually, an accurate fit is obtained.

The backbone can now be cut to length.

A little trigonometry to ensure the forks are inclined at the correct angle before any cutting takes place. 

Ensure that both wheels are on a horizontal surface and the above chart is taped vertically 

to the wall behind the bike, then simply line up the forks with the chosen angle by line of sight.

Measure twice, cut once.

The tube has been left slightly proud of the edge to assist in the brazing process.

It will be filed flush afterwards.

The final job is to hollow out the stubs for all the reasons previously stated.

At last we can now do a dry assembly to see how it all fits together.

Still to do on the backbone is to make the step which is a simple folded piece of steel brazed to the left fork leg. I also need to drill and tap the holes in the rear fork crown to allow a mudguard to be mounted.

In other news, I have promised my lovely wife that I will build her a new deck when spring arrives. I fear that my shed fettling will have to take a back seat for a period if this good weather continues. I did try to bribe my brother to come and build it but he pretended not to hear me.

The Abingdon Ball Head - Part1

We've had some weather these past few weeks. Sadly it's not been of the kind that makes cycling enjoyable. This means that my shedweeks have been slightly more inflated than usual and consequently I've been busy. There are lots of photos for those that are hard of reading.

Do you recall the patterns that I took to the foundry some time ago? I received the castings back quite a long time ago, I just didn't get around to doing anything about them. Or telling you.

Freshly cast and very hard.

I've had them cast in p20 which has a similar composition to 4140 chromoly. p20 is classified as a tool steel (it's used for mouldings) and since the castings are small they have cooled quickly and become chilled. the castings were hard, too hard to machine so I took them to the heat treatment place around the corner and had them annealed. They were Rc52, they are now Rc31, still too hard for high speed steel tooling but OK with cobalt or carbide. I know this through experience after burning several HSS drills.

The first job is to make the Abingdon ball head so I can get the neck properly located in the head. This will then enable me to file the backbone stub to the correct angle so that the backbone will sit at the correct angle to the wheel.

I've been doing a little more research on the Abingdon ball head and it turns out that it was patented by Isaac Watts Boothroyd (of Ellis & Co. and later Crypto) and Philip Louis Renouf. I need to to do some more research on Renouf, his name pops up repeatedly in the 1880's. So it seems that Ellis & Co. the makers of the facile, invented the ball head and the Abingdon Cycle company then made it under license and also supplied it to other manufacturers. I have recently got hold of a copy of the American version of the patent (as stamped on the head) and when I figure out how to do it it, I'll make it available for download.

The American patent for the ball head, the text references 

the English one by number, 3294, as stamped into the head.

The original facile had all the correct pieces including the lamp bracket which mounts on the head by a lock nut on a lock nut (this will become clear). There were two options for the first lock nut, you could either have one flush as in the patent drawing or have one proud so that the lamp bracket could be mounted around it.

The original components.

As usual here is a series of photos describing the steps taken to machine all the bits.

mark the centres on either end and drill through, 

even using cobalt drills this wasn't easy, I ended up using carbide drills.

Then create the 60 degree inside cone on either end. I bought a special cobalt cutter for this, it was very expensive and I haven't told my lovely wife yet.

Next make the bearing cups that fit into either end. These each contain 10 x 5/32" balls and I needed to do some calculations on these to ensure the wall didn't become too thin.

Rough out the inner bearing surface.

Then machine and polish.

Finally, create the 60 degree cone. Part of by drilling through.

Then make the axle and the top cone, washer and lock nut.

Turn the axle between centres since it was frequently removed to check clearances.

Rough cut the thread and clean up with a die.

Mill the flats for the lock washer.

Turn and thread the cone.

Then knurl the outer edge and part off.

I hate knurling, it's a brutal, unsophisticated process.

Machining the grooves in the lock nut with a slitting saw.

Actually two slitting saws mounted side by side.

The component pieces.

The complete assembly then fits together in the same way as a pedal axle.

It takes standard ammunition...

Next week I'll make the top lock nut and file the stub to fit the backbone.

In other news, my lovely wife celebrated a significant birthday (-1) this week. In the usual manner I had asked for a concise list of potential presents well in advance. She wanted one of these, specifically the simple, non digital version that the Queen has. This is just as well since New Zealand is a simple, non digital country that the Queen has. It is possible to buy them in Australia but not here. I contacted the parent company, who have an office in Auckland, and asked if it was possible to buy the analogue version anywhere in NZ, they promptly replied that no you can't buy the analogue version in NZ because we don't have digital radio yet. I didn't reply.

I have ordered one from England and it will be arriving real soon now.

Wheel Building

It's surprising how little fettling you can do with the tops of four fingers missing (see below), however, I've tried to be a brave little soldier and this week I've built the wheels up. If you recall, I'd been itching to do this but I had to wait for the paint on the rims to cure properly. Lacing the rims to the hubs is easy and just requires poking spokes through the rim and screwing into the appropriate hole in the hub.

I started with the rear wheel as it is smaller and I can fit it into my wheel truing jig. 

Radially spoked wheels go from loose to very tight in about a turn and a half, so it is important to take it easy when starting off otherwise the rim may well be straight but not very round. The strength of the hollow steel rims means that there isn't a great deal that can be done about larger bumps and kinks in the rim, these have to be worked around as best you can. Also the wheel has to be trued so that the outer, hollow well where the tyring sits is true, not necessarily the sides or inner edge. 

Spoke grip in use.

The spoke key used is a special little clamp that is tightened onto each spoke in order to turn it. This takes a little time as you can imagine and means that the process cannot be hurried. These spoke grips are not uncommon and can be found relatively easily. They were made in quite a few variations and it is fun to collect as many types as you can. Not many people outside of this antique cycle world would know what one is used for but since they are small they are thrown in a drawer and forgotten about. They seem to have been made in large numbers as I have seen them advertised for sale in catalogues as late as the 1910s, though not for their original purpose. I made a small run of replicas some years ago and I've been using them since in preference to my originals.

Abingdon King Dick Spoke Grip advertised in 1912. This is the same Abingdon Works Co. that made the Abingdon ball head on the geared facile. I suspect that spoke grips were made in vast numbers and these advertised here are New Old Stock rather than current production.

Before I can lace the front wheel I need to machine the bore of the sun gear, this is the main gear that mounts to the end of the live axle. When the wheel is built it would not be possible to offer the axle up to the lathe to check for a nice fit.

This really does have to be accurate as all the torque to drive the machine

 relies on this fit, sloppiness would soon cause excessive wear and failure. 

Checking the fit.

Actually, I got a bit carried away and made the entire blank rather than just the bore. I like turning and the time just seemed to disappear. The gear is made from 4140 as it will need to be hardened. I may carry on and finish it off before I do anything else, I don't like leaving things half finished.

The front wheel was laced first and then trued by installing into the forks and truing in situ. 

Now that both wheels are complete, it is possible to get an idea of the scale of the bike by comparing it to other contemporary designs. It really is tiny.

As compared to a contemporary bicycle...

...and as compared to a contemporary safety.

In other news, Le Race didn't go exactly as planned. I'd stayed the night in Christchurch so I could just ride around the corner to the start in the morning. I got a good position on the grid and I didn't need a pee as the race started so pretty good so far. The usual high speed sprint down Colombo street (on wet roads) was followed by the first climb up Dyers Pass. I felt great and was pretty close to the pointy end of things, I was climbing well and riding comfortably when I got a rear wheel puncture. Glass, it's always bloody glass in Christchurch and this was on a new Vittoria open Corsa, my all time favourite tyre. I changed the tube and blew it up with one of those new fangled carbon dioxide cylinders but by this time I'd lost minutes and hundreds of cyclists had gone past me. Starting off again in my haste, I left my glasses at the side of the road. About now I realised that a decent time was not going to happen so I decided to just enjoy the ride. As I was now towards the back of the race amongst the slower riders, I found I was having to overtake everybody to climb at my comfortable pace, this is not too easy with large bunches without crossing the centre line and I was held up in the early stages. My bunch going across the flats was only about 8 riders and with most people having a go at the front we were still pretty slow. Le Race only really starts when you begin the climb up to Hill Top,

I love this section of the race and made up a lot of time on this hilly bit. 

As we approached Akaroa, I was catching riders I'd been with at the start, then came the final descent into Akaroa. Long Bay Road has a bad reputation as a dangerous descent on a bike. True, it starts above 600m and less than 6km later is at sea level. True, it has a crappy surface. True, it has many sharp bends, some of which are off camber, some tighten up on you and some are covered in gravel. True, the exposed saddle often has a nasty cross wind to catch you out.

Now, where Long Bay Road rejoins the main Christchurch Akaroa Road, the race route turns hard left and goes down the Old Coach Road. This road is very steep and requires care, unfortunately I was descending like a complete twat and lost the front wheel on the first right hand bend. Remember those wet roads? The slide took ages and I had time to consider my impending doom before I comprehensibly grated myself down the coarse chip seal. The marshalls were alerted by following riders and I was in the back of an ambulance in just a few minutes. When doing these kinds of rides, I make a point of thanking the marshalls as I ride past, it's volunteers like these that make these events possible, just something to consider. Anyway, the marshalls and the St. John Ambulance guys were fantastic. Roughly an hour later, I gingerly rolled down the remainder of the hill and crossed the finish line under my own steam to sympathetic applause.

Ouch.

Later as Sue & Colleen from the Akaroa Health Centre stitched me up, I reflected on how lucky I had been not to break anything. Now 10 days later, I'm well on the mend although my right knee will be a long time healing as I sanded it right down to the bone. I haven't looked at the bike yet, I daren't. It's my favourite 'modern' bike, a 1996 Argos built for me from the first batch of Reynolds 853 with lovely clunky 8 speed Campagnolo Record components. I think it's mostly OK. My beautiful new disco slippers are ruined as is my helmet. The clock read 4:11 as I crossed the line, my bike computer said 3:13. I think without the incidents, I'd have done the ride somewhere between 3:00 and 3:10, not too bad for a old, fat retrogrouch on a 'vintage' bike. I'll have to do it again next year. If my lovely wife will allow it.

Brazing the Front Forks

As promised last time, I've been directing my efforts at getting the front forks brazed up. There seemed to be an endless list of things to do before I could light up the oxy-acetylene though. I needed to hollow out the stubs that extend into each of the tubes. As mentioned before this is for several reason, firstly it helps to prevent cracks forming at the junction of the stub and the tube. Secondly it makes the brazing process easier as a large mass of material that is hard to heat is removed, this helps to prevent overcooking the tubes. And last is the obvious weigh loss from removing metal. In this case, hollowing out the 6 stubs (2 per 'knee' and 2 on the head) removed a pound of weight (0.45kg). Not insignificant.

However before I hollow out the stubs, I need to stamp the top of the Abingdon Ball Head with the appropriate patent information. I need the stubs to be solid to support the hammer blows required to do this. I admit to putting this task off for ages, the potential to completely screw it up is high. Every now and again I'd have a little practise on some scrap until I had developed a method of working that reduced the chance of errors. I was still shaking when I struck every letter and number though. The hard bit is to get the individual letters to be correctly aligned vertically with respect to each other and correctly spaced. My method is simple, I use 4 layers of masking tape to define the lower edge of each letter or number, placing each stamp onto the surface of the workpiece and then sliding until it contacts the ridge of masking tape. With practise, it becomes easier to apply the same pressure against the tape and the letters then line up with each other. To get the spacing correct, I mark the tape ridge at the correct intervals and then line up each stamp with the next mark.

It is worth noting that letters or numbers with less area, such as I and 1, require a lighter blow

 other wise they appear over struck compared to larger letters.

The results aren't too bad although the I is too far to the right,

I'm not too bothered as the original is also clearly hand stamped.

With this onerous chore out of the way I can now hollow out the stubs. I very roughly drilled and milled out as much material as possible before getting stuck in with a carbide burr mounted in an air die grinder. I bought a cheap Chinese die grinder that will run at 25,000 rpm without over running my compressor too much. Think of a dentist's drill on steroids. You really do need those high rpms when removing steel. It is a truly horrible job and results in thousands and thousands of razor sharp needles of steel *everywhere*, regardless of how carefully everything else is covered up. I've been digging steel splinters out of my fingers (and feet!) ever since despite wearing a ridiculous amount of PPE.

Roughly removing as much material as possible...

...before getting the carbide burr out

A pound of steel was removed from these 6 stubs.

Now I need to make a jig to hold everything in the correct location whilst the heat is applied.

I happened to have some angle iron in my magic cupboard, so this got chopped up... 

...and with some 10mm threaded rod, I can locate all the bits in a frame that doesn't move.

I used 40% silver solder to keep the heat on the 4130 chromoly tubing down. Silver solder has suddenly got really expensive, still I only need the one kidney. It all appears to have been successful with good penetration into the joints and very little distortion from the heat, although one of the blanks in the bearing house was *very* hard to get out afterwards. Fortunately I had previously made a 1.75" x 26tpi tap and had it hardened for exactly this eventuality and I was able to clean out the threads nicely.

This week I'll clean up the joints and mill the slots for the locking tabs. Then I can continue with the gunmetal flanges. Then I can make the spokes... etc. I've set myself a goal of having the frame sat on it's wheels inside of a year. I'm already 6 months into the project and more or less on track.

In other news, I've finally managed to arrange a small aftershock for my parents, We were having dinner in Christchurch and were rudely interrupted by a vicious little 4.6, I don't think they liked it much. We also had a nasty little swarm last night but fortunately my parents are away on a tiki tour of the West Coast this week. I'll try and save a few for their return.

In more other news, someone seems to have stolen summer this year. We haven't had one yet, does anyone know where it is?

Patterns

This week I've been making pretty patterns in my shed.

I use patterns most days in my job, but I don't mean that kind of pattern, I mean casting patterns. Although of course it amounts to the same, something easily repeated.

You may recall that some weeks ago I requisitioned Mr. Middleton's wood lathe to turn up the blanks from some 'donated' apple wood.

Part payment for my appalling injuries sustained whilst at Mr. Middleton's house.

I've spent a little time removing some bits and adding some more to make the final shapes. Isn't it quick to make stuff out of wood? I don't do it very often but I quite like woodworking. I often think that working with metal is digital or binary in that what you make is either right or wrong, it fits or it doesn't. Whilst wood is analogue and you need to allow for inconveniences like grain, knots and movement. Wood is a far more emotional medium. But what do I know?

I do know that I now need to clean up my workshop again as it has a pile of wood shaving instead of swarf. I think I'll bribe my children to do it for me.

Some slots to allow other bits to be firmly stuck on.

Some more bits to be stuck on. The filler to radius the corners is a two part epoxy resin.

The elliptical profile has been left oversize to allow for shrinkage and to make adjustments
 when filing to fit the  backbone. The sealer is also a two part epoxy compatible with the filler.

The paint is just an automotive primer.

I'll take these to the local foundry next week and see what they say.

In other news, last weekend was the Santa Parade here in Christchurch. The route was different this year as the traditional route has been somewhat munted by the earthquakes. We were invited to take part as usual on the antique bikes and we had a good turn out this year with quite a few younger riders which is good to see. The weather was as hot as it always seems to be for this event and the crowd was as big as usual despite the route change. An estimated 100,000 people lined the route.

This bit is actually part of my commute, Usually more cars, less people, different bike