Friday, 11 April 2014

Levers part 5 - The end is nigh

Things have been progressing this shedweek, so much that the bike is very nearly finished, I'm just waiting for some paint to dry. But we're getting ahead of ourselves.

At the end of the last post I mentioned that I just had to glue the lever bits together. This proved to be mostly true, although in my haste I made a monumental mistake that had me getting all sweaty and grumpy.

I'd made a little jig to hold the lever pivot and the bottom con rod mounts in the right locations. Both of these parts are bolted to the jig with appropriate spacers underneath and then pressure is applied to the end of the lever with a set screw to hold everything in place. I had a short window of opportunity to get everything silver soldered up last weekend and arranged with Pete to borrow his gas set. In a great rush to get back to my domestic chores I set the jig up wrong and brazed the bottom mounts on backwards relative to the pivots.

You can't easily tell but the bottom mounts are wrong.
I realised shortly after I'd just brazed up the second one incorrectly.
Pete photo bombed my picture and he's not funny.

It's far harder to unbraze something as you have to get the entire thing hot enough to melt all the braze rather than just the bit you're on at the time. Pete helped enormously as I don't like making mistakes and was beginning to lose the plot a little. I then had to clean up the joints again, re-flux, re-jig and then reheat for a third time in the right place. Of course by now, I'm a little flustered so I forgot to take any photos of the jig to braze the pedals onto the levers. The pedals were bolted together at the same angle and then the bottom mounts bolted together with spacers to ensure that both side were the same. These were easy to braze on as the sections are small compared to the beefy bottom mounts.

I also asked Pete to TIG my broken right hand con rod. I'd chopped out the middle section and replaced it with a section of plate cut to width. The joints are Vee'd out from both side to enable full penetration of weld. Once one side is done, it can be flipped over re bolted down and the other side done. Time will tell if welding nitrided 4140 is a good idea or not.

Once again I forgot to take an 'after' photo. Just take it from me that Pete is a good welder. 
This just needed filing to shape after it had cooled.

Then just clean up the brazed joints, use a tiny amount of filler on the welded joints and prep. for painting.

Then of course it started raining and it hasn't really stopped yet. I had a brief respite where I managed to get a top coat candidate on before it started again. This means that the paint will take ages to dry.

The first top coat candidate, I've just checked and they will need another coat.

In the meantime I've made the nuts and bolts for the pedal rubbers. I cheated and started with some coach bolts, these just needed the square section machining off and a slot cutting in the cap. Then cut a new 2 BA screw thread at the right length. The nuts are just smaller versions of the same ones all over the rest of the bike. They require the special tool to do them up.

This picture is taken shortly before the acid bath to prep. them for plating. 

I have a line on some genuine ribbed pedal rubbers but in the meantime, I've fangled some from some milking tube.

There are two diameters here, one is a very good fit inside the other and the bolts slide nicely down the central hole
The rough sawn ends are very easy to clean up on a grinding wheel.

So I'm now just twiddling my thumbs waiting for the enamel to dry in rather damp conditions.

The 10 day forecast is for a little rain so I may have a wait on my hands. 
Everything is now made, I just need to do the final assembly.

In other news this weather means that we're having a bumper crop of fungi this year. My lovely wife found a giant puff ball as big as a space hopper. she took it to school to show the kids and now she receives presents of giant horse mushrooms from the parents that have paddocks. It's a rural school you see and I'm not complaining, I love mushrooms.

Our garden just grows large numbers of fly agarics but as I don't own a reindeer they go uneaten.

My lovely wife says I'm a fun guy, maybe that's why I'm kept in the dark and fed shit.
Oh dear.

Tuesday, 1 April 2014

Levers Part 4 - Pedals

I got the levers back from SSM this week, actually I got them back the same day as I took them in. I like SSM, they look after the little guys. Now that they have been normalised it means I can file the welds by hand, there are no longer any hard spots or residual stresses from welding or work hardening from bending and rolling. When you buy chromoly it comes in a normalised condition, I'm trying to get back to that condition. Time will tell if I have been successful I guess.


A trial fit.

This week I'm going to make the pedals

There's not much to them really, I mean not much material, there's heaps of work to be done.

The first job is to make the boss that sits on the ends of the levers. 
I made this slightly tapered to be a nice fit. It's double ended since I'm going 
to make both pedals as one assembly to start with.

The body of the pedals will be made from an old 1" seat post, I need to bore a hole for the boss to locate through,
 this seemed the easiest way to do it. Locate at centre height...

...then just drill and bore through until at size.

Next make a little jig to hold the strengthening gussets at the correct location. 

The gussets are both made from the same plate. Have I ever mentioned that I enjoy filing?

This slips over the boss and holds everything square when clamped up. 
My son asked why I was making Cybermen

Next ask Pete to Kung Fu them up for me. Don't look at the arc. You did didn't you?

Then give the welds a little tickle with a mini carbide burr in my Dremel. 
Have I ever mentioned how much I like my Dremel?

Then saw the assembly in half.

The central part of the boss is not required... it gets removed.

Then decide which is the right and left pedal, they are not symmetrical in two planes you see. There is the obvious bias to the width of the pedal and also the pedals are slightly tilted forwards.
The pedals are fixed to the levers and cannot rotate, this means that as the levers follow their arcs, the pedals change their orientation to the feet. This forward tilt is to compensate a little for this otherwise at the bottom of the stroke, the little tab to prevent your foot going into the spokes is at the wrong angle to be useful. The width of the pedals is much narrower than would be considered normal today, these pedals are only 3.5" wide. People were generally smaller back in the day and certainly had smaller feet, the style of shoe worn was also narrower as an attempt to make the feet appear smaller. Look at contemporary illustrations of Victorians and the feet are always drawn as tiny as possible, funny eh?

The distance between the pedals is also worthy of a mention. In relatively recent years, the term 'Q factor' was invented to describe the width between the outer faces of cranks on a bicycle. A low Q factor was deemed desirable and triple cranks with a wide Q were disparagingly called 'birthing cranks'. The inventors of this modern term may or may not have known that the Victorians already had a word to describe this dimension. They called the distance between the centres of the pedals the 'tread' of a bicycle and again a narrow tread was deemed desirable. Manufacturers used to boast about how low the tread was on their machines. The figures are widely quoted in the reviews and catalogues of the day. A tread of 12.5" was considered very narrow for a penny farthing. The Singer 'Xtraordinary was published at 10", and a conventional facile was also 10". The tread on the geared facile is very, low at 8.25" and Ellis & Co. certainly advertised the fact. This is mostly because it has a small wheel and simple trig. means that a smaller wheel with the same angle spokes will have a shorter axle. But also because the pedals are biased towards the outside, 2" versus 1.5" and the measurement is rather mischievously made from the centre of the lever not the actual centre of the pedal. Slightly misleading advertising is not a modern phenomenon.

Slightly forward biased pedals.

Next make the little end caps...

...and silver solder them on.

Next week I'll glue the all lever parts together.

In other news, I'm afraid there is none, I've been working too hard for any other stuff to have happened. An hour before work in the workshop and then several hours after work trying to get this bike finished. I'm hoping that next week will be a little more relaxed.

Carry on.