Wednesday, 14 December 2011

Bearing All

Last week I mentioned that I would take my pretty patterns to the local steel foundry. Unfortunately my foolhardy foundry foray floundered. The foundry wasn't at all interested in a small run of one offs. I still have a couple of less local options before I try even farther afield, this will all have to wait until the new year though as New Zealand stops for a month at Christmas for the summer holidays. If this fails then I'll just have to fabricate the bits from scratch rather than cast them. Sigh.

Also, I went to pick up the tubing for the backbone from my local supplier. A piece of 1 3/8" 0.049" chromoly that I ordered two months ago. It seems that my supplier isn't. I'll have to look further afield for this as well. Trying to use local companies can be too trying.

So, in the meantime I'm going to start work on the wheels as a complete break from the recent disappointments. The front hub has a most complicated arrangement of bearings, featuring a double row of balls per side and then a live axle running concentrically through the hub on a pair of bearings. The hub has 6 bearing surfaces that all have to be concentric, I'll need to plan how to machine this carefully.

However before I can start on the axle, I need to make the bearing races that screw into the bearing housings, the knees, previously made.

Starting with a lump of 4140 steel that happens to be ground at 1.75" already

Centre it carefully and cut a 26tpi thread along enough of a length so that I can make all four races without removing the work from the chuck so that the threads and the bearing surfaces are all concentric.
Checking the fit.
Bore a big hole using my fabulous new boring bar.
Rough out the bearing surface as a plain bore with a 45 degree bevel at the inner end. 

The idea is to minimise the amount of material to be removed by the form tool as much as possible. This photo is from the second bearing off the bar as I forgot to take a picture of the first one I made.

Then use a form tool to profile the bevel to a radius of the correct size.
 The picture makes this look easy but in practise I had a nightmare on this job. Using a form tool on an external surface is hard enough what with all that chattering going on distracting you, but internally it all gets harder still, literally. I initially used a ground piece of HSS as my form but found that if it rubbed even a little, then the 4140 work hardened and I got extra grumpy. I had to use carbide to prevent this and slow the lathe right down. Carbide plus slow is not a normal combination, but it works really well in this application. Note that I also had to relieve the tool holder to prevent fouling on the work piece.

With the form cut I can then polish the bearing surface.
I'll need to do this again after I've had them hardened.

Then part off each bearing with enough meat left to clean up the inner, parted off, edge.

The inner races have an extra flange extending inwards, 
this forms part of a labyrinth seal with the hub flanges, more later.

I still need to machine the castellations on the outer races that allow the adjustment to be locked. I'll need to figure out a set up for that on the ever versatile Myford.

In other news, I've set up a small work bench with a vice in another part of the shed for the kids to play with. I'll get them a selection of tools for Christmas and let them cut off digits at their leisure. They don't read this blog, so I won't be spoiling any surprises.

Note that the vice is on the left, both my kids are sinister despite my wife and I being dexter. 
Weird eh?

Wednesday, 7 December 2011


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

Wednesday, 30 November 2011

Inflamed Wimp Glands

This week I've done nothing. Well that's not strictly true since I did manage to clean up the workshop, but I've not been able to make any progress on the geared facile. I had rather hoped to be able to work on the wooden patterns this week but my ribs said otherwise. In true man flu tradition, I have hurty ribs.

Doctor, doctor it hurts when I do this
Well don't do it then, stupid boy. etc...

Apparently I have two cracked ribs that will take 4-6 weeks to weld. I suspect that Mr. Middleton's bike was the initial cause and then the act of Dog last week compounded the problem. Either way, I can't use hand tools at the moment even though I have some fantastic pills to take the pain away. Being a road cyclist, or 'stiffback' as my kindly brother Sam refers to me, I'm still able to ride a little. Indeed, not being in the workshop means I've ridden 700km in the last two weeks so I'm getting this much sympathy from my wife.

Normal service should be resumed next week.

Wednesday, 23 November 2011

An Act of Dog

This week has been momentous in that I now have the first assembly complete. I've finished off the head to the point where I can fit the forks legs to the head, the knees to the fork legs and the lower legs to the knees. Everything jiggles nicely with no stress to hold it all in place, so hopefully when it is brazed up it will stay where it should without too much distortion and misalignment from the heat.

The'axle' is just a machined spacer to hold everything square and concentric
However let's not run before we can walk. There has been a lot of hand work this week underneath the head to clean it all up. As before here is a series of photos when I remembered to take some.

The mounting point for the front brake pivot has also been machined, this required some careful trig. to calculate the angle and depth to ensure that the hole didn't break through either below the head or into the central bore.

I've tapped it at 1/4" bsf, I wanted to use 1/4" bsc but I didn't have a plug tap in that size.
I've rootled around in my magic cupboard to find my stash of silver solder and failed miserably. I suspect that my wife has been funding her extravagant lifestyle by discreetly selling it on the local black market. Or I probably just used it already. I did find lots of skinny silicon bronze brazing rods though, so maybe I'll just use that to glue it all together instead. I'm undecided if I'm going to finish the lever pivots before I braze it all up or if I braze up what I have completed already. What do you think?

My workshop and lathe need a major spring clean after all this work on the head. Recall the original billet I started with that weighed 18lb 3.5oz (8.26kg). The machined head now weighs a svelte 2lb 1oz (0.93kg), so I have 16lb 2.5oz (7.33kg) of swarf and filings lying around (mostly in one pile). My wife is getting grumpy when I bring it into the house on my feet so clearly a clean up is needed in order to maintain certain marital benefits.

Next week I'll finish off the casting patterns and then decide what to work on next.

In other news, a few of us rode the Little River Rail Trail at the weekend, We rode from Motukarara to Little River, had a picnic lunch and then rode home again.

'04 & '06 Royal Enfields. The wagon has a wooden chassis and  is older by 25 years.
Little River station building
It was a beautiful day that turned into a roasting Nor'Wester. On the way back, we were riding straight into the teeth of the gale (of course). The kids did really well and both rode the full 45km, the longest ride for both of them. Less fortunate was another youngster that hit a rock next to Lake Forsyth, wobbled and then plummeted 5 metres down a rocky bank and into the green, algae filled water. She disappeared from sight underwater, all tangled up in her bike, but quickly resurfaced. Fortunately we witnessed her disappear so were on scene very quickly and I was able to scramble down the rocks and jump in to assist her out of the toxic soup, She was miraculously unhurt other than bruising, just very scared and shaken. Her bike was badly damaged but she had clung on to it in the deep water and I was able to fish it out. I've since heard that she is all OK which is wonderful news. I confess to having a wee drink that night, I'm not a great swimmer.

In more other news, I've taken another tumble off my bike, the second in 10 days. Commuting home through a park in Christchurch, I was JRA and about to overtake a pair of elderly ladies walking their dog. I'd pulled well of the tarmac path and onto the grass so I would pass without scaring them. As I'm level with them, their dog very suddenly turns sharp left and runs straight under my front wheel. Fortunately, I landed on the same side as last week so I just freshened up my existing gravel rash and re-wrenched my back in the same spot. The ladies were very apologetic and concerned but after I'd been able to get up and straighten the bars etc. I pointed out that it wasn't really any one's fault and there was no real harm done. It was just one of those things, an act of Dog.

Wednesday, 16 November 2011

Foul Play Suspected

I have been the victim of a blatant attempt to delay progress on the geared facile. This past weekend was a long one here in Canterbury, the powers that be giving everybody the Friday off due to my birthday. Or something. We chose to visit Mr. Middleton and count his bicycles. This took slightly less time than it should.  Consequently I have spent less time in my shed than usual and more time in Mr. Middleton's shed. Mr. Middleton has capacious sheds, so much so in fact, that it is possible to get lost in the labyrinth. I've taken to filling my pockets with torn up scraps of paper and discreetly dropping bits so I can find my way out again. On one such foray, I swear I glimpsed a bewildered moa in one of the deeper recesses.

Mr. Middleton has constructed this thing:

Any resemblance to a well constructed bicycle is purely coincidental
It is a front driver that vaguely resembles a Crypto, only not as well made. He pressed me to try it out on the gravel track through the orchard behind his house, urged me quite hard as it turns out. He also contrived for his son to accompany me on a similar but three wheeled front driver. Knowing that I cannot resist a race, he had obviously instructed his son to increase the pace a little at a time until we were haring along at a very high cadence. Then out of nowhere he deftly threw a pothole right in front of me and I took a header straight over the bars and landed on top of myself in a bloodied heap. My legal team are sharpening their pencils...

As part compensation I forced Mr. Middleton to give me some well seasoned, quarter sawn, apple wood and use of his wood lathe. I've started to make the patterns for the neck and lever pivots. I'll finish these off after the head is complete.

More bits are to be added to these shapes - more later
This week, in my own shed, I've been fettling the stubs for the upper end of the fork legs. Once again pictures speak louder than words.

Marking Out
The fork legs are angled forward at 6 degrees,
this angle needs to be carefully  milled
The angle can be seen here in the side on shot. 
Hacksaw diet
Starting to hand file the elliptical profile
One leg complete
I'll try and get these finished orf next week and then carry on with the patterns for the castings.

In other news, Sunday was my birthday. It started well with opening presents in bed with the kids including my new cycling shoes

Disco Slippers
and ended very badly with locking the car keys inside the car and then subsequently very nearly running out of petrol on the way home. It was a comedy of errors, except that it's still a bit too soon to find it funny. Mr. Middleton was clearly feeling guilty when we departed as he furtively pressed some vintage Campagnolo items into my hand. I'll not be bought that cheaply sir.

Wednesday, 9 November 2011

The Neck Hole - head part 4

For various reasons I've not had much shed time this week although I have managed to nip in every now and again. Enough to make the hole in the back of the head for the neck to insert. Compared to the earlier Stanley type head with plain cones, the cutout appears to be much wider. This is because it is. The extra width is to allow the bearings to be inserted. On an Abingdon ball head the bearings are attached to the neck and the whole assembly inserted and locked into the head. This assembly is 1" wide so the width of the cutout has to be a corresponding width plus clearance.

This illustration is from 1887, a year after the patent
I had originally intended to drill out the bulk of the material and then mill the edges clean. In the end I just milled the whole hole, this proved to be the easy part.

It's hard not to mill away part of the threaded rod securing the head to the  vertical slide
Since the mill couldn't remove all the material in the lower corners, I needed to file these to shape. This proved quite time consuming since I had less than half an inch travel on the file tip only. These lower corners are also slightly flared to provide a smooth edge for the neck on full lock (the head is tapered and the neck only contacts at the bottom edge).

The original

My copy. I was pleased that the counter bore has come out really well,
this is the first time that I've been able to see it.
The observant reader will notice a difference between the head of the original machine I am copying and the head I have made. The original is a rare pneumatic model, that was made for 1 3/4" Boothroyd or Dunlop tyres. (I need to do some more research on this). Clearly these new fangled pneumatic tyres are significantly wider than the older solid tyres they usurped. This meant that a new head casting was needed. No need to produce a new neck casting though if a relief is made at the back of the new head to mimic the dimensions of the original size. This is what the curious shaped cutout is for, it allows the original shaped neck to be retained with no modification. Notice in the illustration above how closely the neck follows the head casting at this area. I have only personally seen one such pneumatic geared facile although I know of one other. My geared facile will have 3/4" solid tyres so I am using the dimensions of the solid tyre head rather than the pneumatic head. I suppose I could make some 40" pneumatic tyres but with my shed time as limited as it is, I'll go with solids.

In late 1891, Ellis & Co. and the Crypto Cycle Co. merged under I.W.Boothroyd as Managing Director. Boothroyd was a firm proponent of front drivers and continued to manufacture various models of crypto cycles right up to the late 1890's. Interestingly, the Boothroyd patent tyre was the design that became universal in the USA (single tube) after being promoted by Col. Albert Pope whilst the English preferred the infinitely superior separable inner tube designs (of which there were many). By this time the company was only offering cushion tyres (1" or 1 1/4") or pneumatics, solid tyres were all but gone. This table illustrates the rapid rise in popularity of the pneumatic tyre at this time.

Cycling by H H Griffin, revised second edition 1893.
As with all pictures, click for a larger image
In other news, we have much sadness in the house now that the grandparents have gone home. We all went mountain biking at McLeans Island  to cheer us up. My daughter flying off and leaving us in her dust. I was on a tandem with my son and and we couldn't keep up. Obviously due to the lack of manoeuvrability and extra inertia, obviously. Just last week she won every event in her school sports day except for the discus. She is built like a racing snake though. One day she'll be faster than me on a road bike. I'll think I'll probably take up golf at that point. My in-laws have left their golf bats in the garage for me to look after, have they recognised this already?

Thursday, 3 November 2011

Handling the bars - Part 3

It's curious, is it not, that we refer to 'a pair of handlebars' to describe a bent piece of tubing. Where does this term come from? The answer of course is way back, as with all things bicycle related. Here is a photo of a pair of handle bars. They are detachable and each side is separate from it's twin. On the end of each is a handle. They are also solid, not hollow. They are bars, a pair of handle bars.

This particular example is an 1883 Bayliss, Thomas & Co. DEHF
(Duplex Excelsior Hollow Fork) although many other manufactures had similar arrangements
However, by the time that Ellis & Co. were making the geared faciles, hollow handlebars were the norm. A solid bar of the same OD as a tube (same material) will resist bending better, however a tube of the same weight (cross sectional area) as the bar will resist bending even betterer. The obvious result is that handlebars became hollow with a larger outer diameter and a thinner wall thickness. (A trend that continues to this day with the 'new' standard of 31.75mm - 1.25"). The geared facile has handlebars 27" wide that taper from 0.75" in the centre. So I need to replicate the handle bar mount with a 0.75" bore + clearance for braze.

The first job is to remove all the unnecessary material from around the head. The easy way is to drill a series of holes and then saw between them. I've found that the best way is to start with small holes and gradually increase, otherwise the drill bits can wander into a neighbouring hole. I've struggled to buy decent junior hacksaw blades for years. All the recent ones appear to be made of cheese and bend all too easily. But I digress.
Do you know what a versine is?
An easy way to remove excess
With all the excess removed I can now focus on shaping the handlebar mount into a nicely rounded shape. Strangely, I find it easier to get an accurate circle if I start with a square and attack a corner at a time. I'm going to mill/flycut the square shape and hand file the round shape. Pictures can describe the various steps better than I can.

My father taught me how to use a file many years ago. While an apprentice he was assigned an exercise to make an hexagonal hole in a piece of (unknown thickness) gauge plate and then make a hexagon to fit it accurately in all 12 orientations. All by hand using a file only. Apparently his was the only one that did, such is my upbringing.

The last two stages are to bore the 0.755" hole and then radius the edges of the mount.

Yet another boring photo, this time a boring head,
See if you can spot the mistake. Cross, me? not half.
Next week I'll cut the recess into the back of the head where the neck will insert.

In other news, on Saturday a few of us travelled to Akaroa with our bikes to take part in their french festival . Saturday was a beautiful day with high temperatures, no wind and not a cloud in the sky. The event was extremely enjoyable and we didn't leave until late in the afternoon.

In other other news, I've been given permission to buy a new pair of cycling shoes. This is indeed a momentous occasion since the last ones of I bought were a pair of Sidi Genius 2 in 1994. At the time they were the top of the line road shoes and mine are just about completely knackered after 17 years and more than 150,000 kms. Being a cheap retro grouch, I've been reluctant to replace them with any of the modern disco slippers. However, my very kind wife reminded me that I have a birthday in a couple of weeks and she never knows what to buy me... I've ordered a pair of Sidi Ergo 2 in bright shiny red (to match the bicycles). This pair should just about see me out...