These spindles have been CNC machined in the UK from EN16T. The hexagon on the lower front spindle is not load bearing so is made from stainless steel and then screwed onto the spindle.
 
This spindle set will fit Norton girder forks manufactured between 1932 and 1939 with splayed fork legs as fitted to the following models: Big 4, 16H, 18, 19, 20, ES2, CS1, CJ, 50 and 55. These are all the models from this period except for the 30 and 40 Internationals. Although the top two spindles are the same, the Internationals had parallel fork legs and therefore different spindles at the bottom. We sell these spindles as well so please see our other parts. 
 
Part numbers from the 1933/34 parts book and overall lengths are as shown below so please check they will fit your bike before purchasing. From top to bottom in the first image: 
1 off part number 9266 'Front Fork Bottom Spindle, Front' with hexagon and thread for damper knob. 10'' overall length.
1 off part number 3181 'Front Fork Bottom Spindle, Rear'. 10'' overall length.
2 off part number 3179 'Front Fork Top Spindle'. 9'' overall length.
 
All 4 spindles are 1/2'' diameter.