These are the distinctive Norton girder fork - deep hex bolt and grease nipple that were sometimes fitted to the top spindle area of the front blades, and top crown clamp - which allow for greasing of the top girder fork spindles. They are CNC manufactured using the correct imperial spanner size stainless steel to the original dimensions as original (one of which is shown in the photographs).
The original style of grease nipple is used - but originally these would have had 3/16" diameter thread - which do not look to be available any more with the original 'silver' plated finish, so the grease nipples shown here are of 1/4" BSF thread, but have a head shape of virtually the same head shape and colour as originals.
Price of these is each.
Some years ago I was able to purchase some original Norton versions of these distinctive nuts - which were believed to be Ex-WD16H (see photograph). I believe they were used as greasing points for the top forward spindle of the fork blade, which had two 5/16" BSC holes for this purpose. But using this type of steel nut with a grease nipple mounted in it allowed for it to be used to retain the speedometer bracket (or similar - it is normally used on racing Nortons as a retaining poiont for the racing number plate brackets) - which could not easily be achieved with a 5/16" thread grease nipple alone.
I have also shown them fitted to the two similar 5/16" threaded holes that were used to retain the handlebar clamp on those girder fork variants that used the Top Crown that held rubber mounted handlebars - this type of fork was more commonly seen fitted to Norton International's and late 1930's Norton singles. In truth - I am not sure if they were originally used in this location on that variant of fork - but as when I have purchased original nuts in the past, they were sold as a bag of 4 - I am supposing they could be used for the two top clamp spindle holes as well.
The original nuts (one shown in the photograph) were bored to take the slightly smaller 3/16" thread vertical grease nipples - but these now seem to be unobtainable in the original 'silver' coloured plating finish - instead, the 3/16" thread type commercially available today all have a more modern gold coloured plating - which does not look correct on period Norton items.
Therefore, ours are bored to take fractionally larger 1/4" thread diameteter nipples (whcih we obtain specially from a UK source in silver coloured plating). These grease nipples externally look very little different in external dimensions to the original type, therefore the overall effect is no different.
As will all our special fastenings, these are CNC manufactured with the correct Imperial 'across flats' Hex for Whitworth spanners and have the same greasing bore hole as originals. Finally, we lightly linish the stainless hex after machining to give a nice crisp finish and remove any burrs. The finsihed effect is a very pretty and practical bolt/greasing point.
We assemble the grease nipple in the hex nut so they are ready to use, and as a final touch also apply one of our high quality 1/4" red fibre washers (Item 0097) under the nipple head to prevent leakage, as you should do with any grease nipple. It also gives a more professional finish which should smarten up the front end of your girder forked bike.