| Author | Message | ||
     Randy Roberson Frequent User Username: wascator Post Number: 855 Registered: 05-2009 |
Hi, my switch is missing, along with the two fasteners. Anyone recall the fastener thread type/size? Looks smaller than 2BA. | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 766 Registered: 11-2017 |
The fasteners, machine screw and nut have a very small diameter. Your replacement screws have to fit thru the mounting holes of the microswitch and long enough to go thru the hinge support. | ||
| Alan Dibley Frequent User Username: alsdibley Post Number: 345 Registered: 10-2009 |
They look like 4BA to me - that is just by squinting at mine. Alan D. | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 767 Registered: 11-2017 |
Bentley Heritage does show the switch but not the fasteners. There is also a spacer involved. https://heritage.bentleymotors.com/en/catalogue/partCatalogue/8506?chassisNumber=SRD21285#search-by-categories | ||
| Randy Roberson Frequent User Username: wascator Post Number: 856 Registered: 05-2009 |
Not a 4BA; must be a 6BA or 8BA; I'm trying to fit a modern, more durable limit/microswitch so I may need to make new holes anyway. I'll try a small c-clamp to find a position which will enable to switch work correctly and go from there. Thanks everyone! | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2309 Registered: 05-2012 |
Hi Randy I was unable to source the original switch, the Bulgin S621, so fitted a cabinet door switch instead. https://www.amazon.com/dp/B07YTC8VYH?tag=ftb-seller-20&geniuslink=true It's worked perfectly so far. I did have to extend the push rod slightly by gluing a short length of heat shrink to it. I guess I should have painted the heat shrink black to disguise it but with the air filter in place the switch is hidden anyway. I recall the bolts were 6ba.   . | ||
| Randy Roberson Frequent User Username: wascator Post Number: 861 Registered: 05-2009 |
My fasteners are not 6BA; in fact a 6BA will pass right through the threads. I saw a doc showing them to be M3 x 3/4 inch, but with a washer and nut. Hummm. I can't thread an M3 into it either, so there! | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3283 Registered: 06-2009 |
Randy, Given who made these cars, and when, the probability that they're metric screws is quite small. Since I have no way to determine what the actual size of those fasteners is, even though I have a choice of two cars that have them at the moment, I can't be of any real help here. Brian | ||
| David Gore Moderator Username: david_gore Post Number: 4086 Registered: 04-2003 |
Randy, Can you provide the following details on one of the original fasteners: Thread count: Per inch or in metric, either will do External diameter of thread: Imperial or metric Root diameter of thread if possible: Imperial or metric I suspect the fastener is either a model engineer's BA or Whitworth thread. https://www.fastenerdata.co.uk/whitworth https://maccmodels.co.uk/ba-size-chart/ Either fasteners are usually available from model engineering specialist suppliers.  | ||
| Randy Roberson Frequent User Username: wascator Post Number: 862 Registered: 05-2009 |
I do not have the original fasteners; sorry. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 866 Registered: 05-2009 |
UPDATE: I have installed the new limit switch and it is working as desired. Turns out the fasteners are 6BA, but there is a nut on the other side and the mounting holes are not threaded as I first thought. Thanks for all the great assistance! | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 772 Registered: 11-2017 |
I usually install a SPST toggle switch with Lucar terminals in series with the switch so when the bonnet is left open, it won't drain the battery if there is no battery cut off switch. |
