This distinctive bolt is used to retain the petrol tank on all models of Norton petrol tank from the 1930's - 1950's (excluding bolthru Manx) - they are CNC manufactured in Stainless Steel to the dimensions as the original Norton petrol tank bolt one of which was used as the pattern. Price is each
They are used in conjunction with the dished washer (Item 0123) and upper/lower tank rubbers (Items 0128/0129) to locate the petrol tank to the frame lugs. The upper rubber is of 'top hat' profile and sits on top of the frame lugs isolating the tank from the lugs, then this bolt with dished washer and lower rubber in situ is fed up through the lug and screws into the petrol tank from below.
It is important to remember that all Norton petrol tanks (except for Manx bolthru tanks and Featherbed models, both having their own fixings) had this fixing system and used a coarse Whit profile thread. When fitting these bolts with rubbers fitted the bolt should be tightened until the shoulder of the bolt locks to the petrol tank - they are then less likely to work loose and vibrate off in use. This is a very common issue with this design and it is not unusual to see the thread of the petrol tank has lost its thread or the bolt thread is stretched, as a consequence of the bolt not been screwed fully up to the tank, where the shoulder locks it in place.
As a final point of design - to help aid these bolts not unwinding in use (as they so often do, particularly given that many Norton singles do vibrate) we have had these bolts drilled for lockwire - we would advise you do this, lockwiring them either to the frame or each other . . . they are very pretty, so it would be a shame to lose them! (note - I cannot confirm but believe Norton themselves may have done this for the similar E6745 - the similar bolts fitted to some Gardengate Manx oil tankx bolts - as their 1948 spare parts catalog seems to indicate this)
Final note - As well as being used on Norton SOHC models, these bolts were also used on OHV and SV machines, as well as pre-featherbed Dominator machines