Skip to main content
English French German Italian Spanish

Fork leg drain screw thread size.

Forums

Hi,

The fork leg drain screws are slightly chewed as they were REALLY tight, so I thought, blow the expense, lets buy some new ones.
Andover Norton say part number 060354 is Fork Slider Drain Screw (UNC)

RGM say 060354SA FORK LEG DRAIN ALLEN SCREWS BSW
and 060354S FORK LEG DRAIN SCREW ORIGINAL SLOTTED TYPE BSW

Now I know that the main (only?) difference between UNC and BSW is the thread angle, but does anyone know what the thread actually is?
And would you worry?

Thanks

Tony

Permalink

Mk3 commando fork drain screw is UNC. Whitworth will fit, and i wouldn't worry about it, the difference between 55 and 60 degrees in this small size is almost unmeasurable. You would need a magnifiying shadowgraph to see the difference. Certainly the tolerance in manufacture would make these two screws interchangable (which they are)
Earlier bikes had 1/4 CEI thread (same tpi as 1/4 BSF but 60 degrees) 

Permalink

After struggling and chewing up a few ,i now always use an impact driver . works every time no damage at all.

 



© 2024 Norton Owners Club Website by 2Toucans