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+--- Thread: Wing Screw Thread ? (/showthread.php?tid=9580)
Wing Screw Thread ? - John P - 11-09-2024
Hi,
Does anyone know what thread is on the wing screws that hold the opening windscreen in place.
I believe they're probably 5/16 but I've no idea if BSW or BSF.
John.
RE: Wing Screw Thread ? - Tony Griffiths - 11-09-2024
(11-09-2024, 05:43 PM)John P Wrote: Hi,
Does anyone know what thread is on the wing screws that hold the opening windscreen in place.
I believe they're probably 5/16 but I've no idea if BSW or BSF.
John.
BSF is easy to distinguish from BSW, the pitch of BSF is so much finer and easily recognised. These two BSF and BSW charts might help:
RE: Wing Screw Thread ? - John P - 12-09-2024
Sorry, probably didn't explain very clearly.
I haven't actually got the wing screws to measure but as I'm about to make the barrel nuts they screw into I need to know what thread they should be tapped.
John.
RE: Wing Screw Thread ? - Ruairidh Dunford - 12-09-2024
The thread is normally 5/16 BSW.
RE: Wing Screw Thread ? - Tony Griffiths - 12-09-2024
That's interesting because the replica ones supplied by Willie McKenzie (http://austinrepro.com/general) are BSW - but my '30 Chummy are 5/16 BSF. When the copies arrived, it was obvious that wouldn't fit, yet the barrels into which they screwed appeared to be the same as those from a '29 Chummy (apart from the thread, of course) and not something somebody had made (unless they had taken enormous care). Both threads work with the same efficiency so I suppose either would do if you are going to make your own wing nuts.
RE: Wing Screw Thread ? - Robert Leigh - 12-09-2024
There is more tensile strength in a male BSF thread than in a BSW, but the BSW thread itself is stronger and will better resist getting stripped.