A Gripping Tale

As promised last time, I've spent this shedweek making some T grips.

 This is the one remaining grip on the original, the second one was missing.

Held in place by a single screw.

The originals are made of buffalo horn, this material although not easy to get, is still available. These days it comes from farmed Asian water buffalo and there are a few companies that deal in it. These horns are mostly hollow except for the very tip which is solid. The handles on antique bicycles are at the upper end of the size range of these solid tips and only the biggest horns will do. That's the first problem, you're paying for trophy horns. The second problem comes if you live in a country like NZ that has very strict import laws on animal products. I'm confident that it would be possible to achieve but I only have limited time available in my lifetime and I don't particularly enjoy fighting with bureaucracy. I'm not complaining about the MAF laws by the way, I just can't be bothered dealing with them.

I've spent some time researching valid historical alternatives. It seems that the Victorians used a great variety of materials, some ethical and some decidedly not. I think that getting some fresh ivory into NZ would cause even more problems, not least for the poor elephant. Lignum vitae is an interesting wood you know, it's also massively over harvested and now virtually extinct. However, I like to recycle and reuse stuff and about a year ago I saw a set of lawn bowls in an antique shop. Bowls of a certain age (mine are 1959) are made of lignum vitae and are just big enough to get some handles out of if you use a little ingenuity.

A bowl from 1959, shortly before it met with a saw.

First, sand off the coating to determine the grain direction. 

Then chop into pieces to get the blanks out.

Mount in the four jaw and bore the tapered hole through the grip, 

by taking the chuck off with the work still mounted I could repeatedly check for a good fit.

Flip through 90 degrees and drill and tap the hole for the retaining screw. Amazingly, this stuff is hard enough to take a screw thread, it was also unmarked by the jaws of the chuck. It machines beautifully by the way, with a lightly perfumed odour, the wood is very oily and the cut self lubricates. You get no problems with machining the end grain at all, it appears to be uniformly dense. I experimented and sure enough this wood sinks in water, decidedly so.

The blocks I have are only just long enough to get the grips out of so I need to glue some temporary stubs to either end so I can turn them. Gluing lignum vitae seems to be a topic that raises as much debate as greasing/not greasing tapered bottom bracket axles. In the end I rough sanded the ends for some mechanical interference with the glue, I also wiped with a solvent to remove the surface oil. I then glued using Araldite, a common two part epoxy.

Battersea Power Station

I could then mark and centre drill each stub so I could turn between centres.

Turn to shape until nearly parted off then remove. 

Snap the glued end off and hand file the end profile.

Then place on the handle bars and sit on the bike. Rotate until comfortable, mark this position and make the hole. Finally run the tap through the grip and the bar.

The last thing to do is to file the ends of the bars to match the profile of the T grip. 

The grips are held very securely, there is no play or movement at all. I'm pleased with the result, I now have 3 of the 5 contact points finished, the remaining two being the 'pedals' on the end of the levers which will probably be the last parts to be made.

The total weight is now 34.75 lbs (~15.75 kg)

I think I'll make the brake hardware next, I'm itching to get started on the driving gear but if I do that first then I'll just want to ride it and then rush the rest of it.


In other news, I have been gently reminded that I have not yet finished the deck I promised that I would build for my lovely wife back in the spring. In truth I haven't even started it yet. She pointed out that even Mr. Middleton has managed to build a deck in the meantime. I'm going to have to get on with it, sigh.

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.

Tyres, Teeth & Tuhoe

I've haven't had much time to actually do much this week although I have spent time working out how to make the backbone, more on this later.

The tyres are red, they are not pink darling.

I've had the tyres fitted to my wheels, or more accurately, the tires since I've used the American system rather than the English one. The English system uses a spiral of wire moulded within the rubber. The tyre is cut too short for the rim and and inch or so of the spiral exposed on either end of the length. Then by twisting the rubber the wrong way for the same number of revolutions as coils are exposed on the spiral, the tyre can be joined and the spiral screws into itself and the gap is closed. The loop is then stretched over the rim and is held in place by tension only. This is usually OK for normal use but recent batches from the UK have been a bit crap. This is what can happen when crap rubber is used, the Rider is Jack Castor from California, he was quite seriously injured but is now fully recovered. This happened on an NZ tour a few years ago, Jack was descending from the Otematata saddle between Omarama and Kurow, notice the 'loop' forming in front of the wheel before it all goes pear shaped.

In contrast the American system uses a rubber extrusion with an empty hole through the middle, the rubber is cut too long for the rim and wire fed through the hole. The wire is tensioned on a special machine in such a way that the excess rubber gets bunched up evenly around the wheel whilst leaving a short section of each end exposed. The two ends are trimmed and silver soldered together. When the jig is removed the gap closes up tightly. The rubber used has been sourced directly from the states and is of very high quality, it wears well on our rough roads but is still grippy enough to be safe in the wet.

I painted a couple of pinstripes on the rims before the rubber was mounted. I've been collecting images of original Victorian pinstripes for years now. Every time an original machine gets restored another unique reference point gets lost. But don't get me started on that. It is surprising how gaudy some of the Victorian machines were. We tend to think of the Victorians as very straight laced with stiff upper lips and little skirts around table legs lest the men think unseemly thoughts etc.. Actually, I'm not sure that the table legs thing is true but it's a good story. The point remains though, that to our modern eyes, some of the pinstriping and painted decoration seems way over the top. The double pinstripe on each rim is common, I've seen it on many original machines.

Tax free teeth?

Also this week, I've got the gears back from the gear cutter, he has done a fantastic job and I'm very pleased with the result. I will not say if he waived the GST when I waved cash, that would be rude. They need to be lapped to polish the faces but there is also a lot of machining to be done on both gears anyway. I'll oil these and set them aside for the time being as I focus on the rest of the frame so I can get the bike sitting on it's wheels.

This week I'm going to make some more rollers for my elliptical tube rolling mill, I need to make two sets. One for the elliptical backbone and one for the rear forks. The facile I am copying is a later model and has fully tubular fork blades either side rather than the half open style of earlier machines.

In other news, the family was at a loose end on Saturday so we took a trip on the MV Tuhoe moored at Kaiapoi.

MV Tuhoe.

It was fantastic in that old fashioned, slightly naff way. Sunday's trip coincided with the 'Super Moon' so the tidal river was very high.

Oh, that's super.

I particularly liked the way we were allowed free access to the engine room. If you find yourself at a loose end, I can highly recommend it, just wrap up well if an Easterly is blowing.

The engine room complete with engineer complete with engineer's cap.

Gear Blanks

After all that geary theory, it's time to get our hands dirty again. This week I've been making the gear blanks. I had previously started the sun gear blank because I needed to machine the main bore before I built the wheel up, All that remains is to machine the special key way that locks the gear to the front hub.

These pictures illustrates the key way, 

a tapered key fits into the shaped key way and is 

drawn up the matching taper on the hub by a locking screw. 

The original that I measured came apart very easily and has obviously been apart before as the tapered key and screw have both suffered at the hands of an enthusiastic hammer owner. The key (pardon the pun) to getting this kind of interface to work successfully is to have very close tolerances and as it turns out I had two attempts at the tapered key before I was happy. I may need to make another after everything has been hardened and plated, the tolerances are that tight.

The first job is to drill a hole that just grazes the edge of the bore 

and then countersink the outer end for the locking screw to locate in. 

I actually used two end mills for this job rather than a drill.

The next job is to flip the sun gear over and mill the back of the gear 

from the hole into the bore to create the key way. 

Note that the plug to bolt the gear to the vertical slide already 

had a recess machined out. This cut has to be at exactly the right depth.

Then we can machine the key itself, first job is to drill and tap

 a 1BA hole up the centre of a length of barstock. 

The original really was 1BA, I measured it very carefully.

Then without removing the work from the chuck, remount the chuck 

on the dividing head and mill away the excess to form the correct shape.

Finally, mill the 4 degree taper, this is where the size become super critical. 

With such a short taper, if the key is too tall you can't assemble it 

and if it is too short the key bottoms out as it is tightened.

Next make the locking screw, this is just simple turning and threading with two slots milled at opposite edges to adjust it. Of course, I also needed to make the special tool to do the adjusting...

Finally we can test the assembly of the lock.

Then I just need to make the blank for the planet gear, which is also just straightforward turning at this stage. All the fiddly stuff comes later.

Gear blanks ready for the teeth to be cut.

In other news, last weekend we had a local steam extravaganza at Steam Scene. I took the kids and we had an excellent time. A particular favourite being the miniature train rides which seemed to go almost to Christchurch and back. I was examining the gearing (for topical reasons, you understand) on a traction engine when the owner appeared and asked if I was "Claudia's Dad". It transpired that our respective daughter's were friends. During the course of our conversation, the geared facile came up. I enquired where she got her casting done locally and was referred to a small, local Christchurch foundry that should be able to help. I took my patterns and a photo of a geared facile around on Monday lunchtime. Well, again, it turns out we have mutual friends and had attended many of the same events together, we just hadn't met yet. The upshot is that my parts will be cast in steel and will be ready next Friday. I'll be sure to let you know how they turn out.

In more other news, On Sunday afternoon I helped an excitable, young Tinkerbell build her faux pathracer in my workshop. She arrived laden with Jaffa Cakes (I don't do this for free you know) and we proceeded to prep the frame before using vast quantities of my spare parts. Two of her chums from the local tweed riding scene, Dylan and Pete, also arrived and helped out. We finished it off, sans brakes, and she was able to ride it up and down the street before heading home very happy. She has since added some brakes. Tweed Pete also gave me a recommendation for a local gear cutter. I'll give him a ring tomorrow.

A lecture on gears

Pay attention at the back, there'll be an exam later. I'm looking at you Middleton.

I've needed to learn a little about gears and gearing theory in order to reproduce the geared facile. This has all been a lot of fun (we may have to disagree on this point, I'm a mathematician and my idea of fun may differ slightly from the norm) and I need to share my findings. I'm not going to go into great details but a Google search will yield many results on this stuff if you are interested.

Cycloidal or Involute?

The first thing to determine is the type of gear profile, there are two contenders: cycloidal or involute. Historically, cycloidal gears were used almost exclusively up until the late 19th century when the new fangled involute profile quickly became the standard. Cycloidal gears are still traditionally used in clock making and have a devoted following. Involute gears have certain benefits, such as a tolerance to incorrect gear spacing, that makes them attractive to industry. It is easy to distinguish between these profiles by eye.

I've been unable to find an absolute date for when the involute profile was introduced, all references I've seen suggest the end of the 19th century. Of course this is the exact time frame when the geared facile was being produced.

Examination of the original gears clearly suggests that they are involute, 

which means that Ellis & Co. were at the cutting edge of the current technology in 1887.

So now that we have established that the gears are involute, we need to calculate the size of the teeth. For gears in a gear train to mesh accurately they need to have some commonality in the tooth size, this is known as the Diametrical Pitch (Pd), which is the ratio of the number of teeth to the pitch diameter. All involute gears with the same Pd will mesh accurately.

All original faciles that I have measured have 37 teeth on the sun gear and 18 on the planet gear. I stand to be corrected on this but the literature of the day backs this up. The final gear ratio in this simple epicyclic train is calculated as follows:

gear ratio = wheel size in inches x (driver + driven)/driven

with a 40" wheel, 37 tooth driven sun gear and 18 tooth driving planet gear we get a gear ratio of 59.46" or the equivalent of a penny farthing with a 59.46" wheel. Ellis and Co. offered the geared facile in three sizes 36", 38" & 40" and claimed gear ratios of 54", 56" & 60" resp. The actual calculated values are 53.51", 56.48" & 59.46" resp, it seems that Ellis & Co. liked to keep things even at the expense of accuracy.

Note that it is very important that at least one of the gears has a prime number of teeth, this ensures that the gears will wear absolutely evenly. With a pulsed power delivery such as a bicycle, if this were not the case, spots of high wear would rapidly occur where the same tooth was repeatedly under peak load.

So how do we calculate the Pd to be used? We have the number of teeth and we also have the centre to centre distance for the gears, from the literature and also from my own measurements I know that the gears ran on a 3" crank.

Centre distance = ((driver teeth + driven teeth)/2)/Pd

gives us a Pd of 9.16666 teeth per inch

which is unfortunate since commercial gear cutters are always sold as whole numbers (and the odd half size). If I use a Pd of 9, I get a centre to centre distance of 3.056", a little too far off for comfort. Fortunately gear cutters in metric countries use an alternative to Pd known as the module.

Module = 25.4/Pd

so we need a module of 25.4/9.1666 = 2.77

metric gear cutters are available in fractional sizes, the closest to 2.77 being 2.75. If I use a module of 2.75 my centres work out to 2.977", less than half the error of using Pd 9 cutters, also remember that tolerance to incorrect spacing that involute gears have?

The last thing to calculate is the outside diameter of the gear blanks, this is given by the following formula:

OD = (teeth + 2)/Pd

this gives sizes of 4.222" for the sun gear and 2.165" for the planet, which match closely to my measurements of the originals.

gear cutters are available in sets of 8, with a different cutter used for a range of teeth

#8 12-13 teeth
#7 14-16
#6 17-20
#5 21-25
#4 26-34
#3 35-54
#2 55-134
#1 135-rack

So I need to buy cutters #3 & #6 for mod 2.75. The only other variable to consider being the pressure angle which I won't go into. As it happens it was cheaper to buy a full set rather than individually.

I had originally intended to cut the teeth myself but now that I have the cutters in my hand, I've realised that my machinery simply isn't massive enough for the job, these are big teeth. Teeth are usually cut at one pass and require an immensely stiff setup to cut the bigger sizes. I'll contact a local gear cutter when I finish the blanks off. I'd rather get a good job done than screw things up.

Has anybody managed to get here yet without falling asleep?

In other news, I've been for a gentle 50km ride at the weekend. My first since the Le Race debacle. The only bits that still hurt are two fingers on my left hand and my right knee. My right knee was OK after the ride, not great but OK. I still haven't looked at the crashed bike yet. For the ride I selected a late 1940's Raleigh Record Ace (RRA), this was for several reasons: it's very comfortable and I still have a pair of shoes for the toe clips that aren't munted from a recent crash.

A late 1940s RRA. Red, of course.

Not disco slippers.

In more other news, Mr. Middleton and partial family have been for a visit. I was unable to provide an earthquake which was a source of some disappointment. However Mr. Middleton was able to console himself by stealing some of my 4130 seamless tubing. I think he is going to use it to make something from this book written by somebody or other.

Also, Tinkerbell wants to come and see my magic cupboard. Actually, she wants help building up a faux pathracer and I happen to have lots of bits that she needs. Sadly, she intends to paint it british racing green!

Seriously though, there is only one colour suitable for bicycles and that's red[1]. We all know that.

[1] Unless it's black.

Oh, and I lied about the exam.

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.