Interesting thread. I have just laid my hands on one of these to replace a Dawes frame I bent (whole another story).
Going back in the thread a bit, couple of points I'am surprised no-one has mentioned:
Cottered bottom brackets/cranks - The cotter pins need filing to fit exactly, also due to variations in the crank and spindle, if you fit different ones you need to re-file the cotterpins to fit. This mostly means replacing the cotterpins at the same time (for pennies).
When removing them you need to be very careful to support the crank itself - not just the BB. such as with a suitable old socket on a wooden block. This prevents the bearings bruising the races or acquiring flat spots, if this happens it of course means very short bearing life. Obviously for the cranks to be at 180deg they both need to be the same way round. Not so obvious is that the nut should be down when the pedal is forward. This tends to stop them (along with good fit) from working lose - as yours did. I doubt their are many LBS's that know this nowadays.
Raleigh used to make all their own unique threads. The fact that you need a Raleigh threaded BB likely indicates it is a late Carlton. They also used to use 22.1mm instead of 22.2mm stems quite often - although probably not on your Carlton.
These bottom bracket cups are still quite easily available as Raleigh cycles spread right across the British empire and are still extensively used. I have fitted two sets of these in the last three months. I acquired them from
eBay for less than a tenner a set. Finding exactly the right length spindle is not quite so easy. It also seems impossible to find high spec. ones. In the past you could get aluminium cups with forged, machined races fitted and use a hollow aluminium spindle like wise fitted with machined steel races. When used with 25 grade full hardened ball bearings these were IMO better than anything on the market today for weight, efficiency, longevity and repairability. However what you can get, if you are careful, are not to bad. The cotterpins are also still available, they are used on machines other than bicycles. So if by any chance you cannot source them as cycle parts then a machine tool/specialist bolt supplier will be able to supply them by specification e.g. Hereford tool supplies.
May be interesting to note that when cotterless cranks first became available they were scorned by many. They have the problem that they need a specialist puller to remove - so another tool to carry or you can't do roadside repairs. Also early aluminium cranks had the problem that the taper flexed slightly and they kept coming lose (still do sometimes when newly fitted). Sometimes they even cracked across the corners.
Your cycle would just about certainly have been supplied with the option of 5/6 or 10/12 gear variations - using Sun tour derailleurs. I have just acquired a twelve gear one. To retrofit twin chain rings, you will need a longer BB spindle.
When you have ridden a bike like that, apart from bicycles which cover completely new fields (literally sometimes) IMO you can see how all others are for machinery manufacturers to get money out of fashion victims! What a waste of a good fast tourer/clubman to turn it into a fixie :-)
BTW quality for quality their is just about no difference between the weight of aluminium and steel frames. Aluminium frames first became widely available after WWII, when aircraft where being melted down and steel was in short supply. They have subsequently remained as early fatigue problems have been largely solved, on the back of the cheap-expensive nuclear power, we know so well. Mining and refining bauxite (aluminium ore), which is far more toxic than steel production, takes around eight times as much energy. Of course if you want to go the whole hog then ride a Bamboo bicycle and grow it in your garden; these were also made during WWII. They are slightly heavier than steel and said to be like a cross between steel and carbon fibre to ride
I am hopeful that a picture is below, this image came from http://www.bikebroth....uk/carlton.htm which is a great little site. For me it is the holy grail as the Aqua Green Godess in the pic is identical to my bike from the 70s. It clearly shows the sadle that my bike had. Can anyone shed any light on what it was?
