This listing is for a bottom floatchamber nut and brass ferrule to fit early Amac carburettors of the type commonly fitted to Douglas 2 3/4hp and other belt drive models of that era. The nut is CNC machinined in stainless steel, while the ferrule is brass (with Amac sharp taper) to accept 1/4" bore copper pipe.
As can be seen from the accompanyning photogrpahs, this listing is for a float chamber base nut and ferrule to fit early Amac carburettors with the floatchamber that has a bottom petrol feed of the type shown here. This type of carburettor was commonly fitted to Douglas 2 3/4hp models, but I am sure were also fitted to a variety of other early motorcycles up until the late 1920's.
I have two or three of these early carburettors, but the one that was fitted to the current 2 3/4hp model I am building did not have an original float chamber bottom nut - so rather than taking one from another carb, and leaving that short - I took the original nut/ferrule from another carb as a pattern and wrote the CNC programs to make a batch. I found that the unions on these early Amac carbs are very different to most later Amal carbs (which pretty much standardised fuel pipe attachment unions as being 1/4" BSP, and the standard hex that went with that - which can be seen on the accompanying photograph of the made up fuel pipe - on the union that would fit to the fuel tap). Instead, the union nuts on these earlier Amac carbs were a larger hex, the thread was a fine thread (BSC size), not BSP, and most importantly - the taper on the bottom of the float chamber, where the brass ferrule inserts, is a steeper angle than later BSP ferrule fittings.
The original Amac nut is shown in the first photograph on the left of the new nuts we have manufactured.
As you can see - these nuts are CNC machined in stainless steel (which looks almost indistinguishable from bright nickel plating used on earlier Edwardian bikes), and have the flats lightly linished - so as well as fitting nicely, they also look pretty. The brass ferrule has the sharper taper required to fit the Amac floatchamber, and is bored to accept 1/4" bore copper fuel pipe as would have originally been fitted to these carbs (see Item 0981).
Price is for one stainless nut and one brass ferrule (pair)