Roadholder mudguard mounting threads

http://stainlessbits.com/link12a.htmlprovides a useful link when used in conjunction with a parts book to give you the part number, though it is not infallible. The earlier 7" centres forks use 1/4" x 26 tpi studs for the slider to mudguard bridge attachment - frequently replaced by set screws during the bike's life. I am not sue about the later forks. The usual suppliers (Andover Norton/RGM/Norvil) all have them in their catalogues, Andover Norton have illustrations from the parts manuals, though I personally always check with the manual relevant to my bike for confirmation. The part you are after could be 06-7523 (some Dommies) or 06-3189 (if a Commando). I suggest that you check the year etc and consult the available manuals to be absolutely sure. The stay to slider thread can be determined using these resources too.

hello NO there 1/4 Whitworth Lots of members get this wrong Whitworthfor threads in alloy castings like road holder bottoms watch the bottom pinch bolt that break easily if your, not careful yours anna j

No sorry - you're wrong again Ms Dixon. So John they're 1/4 inch X 26 tpi BSCycle thread certainly up until 1966. I'm not sure about '68 and '67 but my Mercury and Commando ( both 1969) were both the coarser 1/4 inch UNC thread. I think that you should follow Alex's advice and ignore Ms Dixon's. That is of course unless you think that someone has fitted the later sliders. The bottom fork mountings on the sliders are also cycle 26tpi thread form but again on my Mercury and first Commando they were UNC thread form - of course 5/16 inch ! Good Luck, Howard