Points cover screws

The diameter would be useful. Are using a thread gauge?.

With the pattern CPC Engineering would make them for you

Hi Dan,

Just checked on my spare engine - the size is 3/16 and the thread appears to be BSF. I tried a 3/16th BSF die and it screws on easily by hand - I haven't got a 3/16th Cycle to test on but at some sizes they are the same TPI.

Sorry I don't have any surplus ones -in fact I am missing one on the spare engine.

Patrick

Dan, the screw looks the same as the point cover screw on a Commando. Can tell you tomorrow if they are the same. Will compare both screws.

Uli

I've a feeling they might be 2 or 3BA

Commando point standoff screws are 2BA, also used on Triumphs and BSA's.

Just checked the Jubilee item again and it is 2BA. I have a 2BA die which fits perfectly- smoother than the BSF.

Odd thing about all this is that at this size BSF, Cycle, UNF and BA are all the same TPI. But I expect to a real engineer there are differences in the thread angle.

No 15 on the diagram:

https://andover-norton.co.uk/en/shop-drawing/240/engine-contact-breaker-timing-cover-oil-pump-oil-pressure-relief-valve#

According to a thread comparison chart I have in front of me:

major diameter TPI

2BA .184 31.4

3/16 BSF .186 32

3/16 Cycle 32

No wonder they are pretty similar

Previously Dan Field wrote:

I just checked my thread gauges again, my threads look to be 1 BA, 2 BA is tiny? Unless of course my eBay gauges are Miss marked?

1BA should be .208 diam whereas 2BA is .184

1BA is not a common size

Hi Dan,

Just rechecked again and confirm that this one is a nice screw in fit in the housing, threads look good, and the 2BA die is a nice fit. In the picture yours looks a coarser thread but not much in it.

I tried a 1BA die and it's a very loose fit on the thread, but not a big size difference seemingly between them.

Patrick

Dan, today I tried the point cover srews from my Commando- they are the same thread and size as the ones from the Navigator.

Pics to follow, forgot my mobile phone in the workshop..

Dan, here are the promised pictures!

Be careful tightening these screws, they shear off easily!

Had to bore out one on my Commando.

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Previously Dan Field wrote:

The pillar screws arrived from Andover Norton yesterday and I'm pleased to say that they fit! The only thing to watch is that the unthreaded shoulder at the top of stud is longer rhan my original and as I have a Boyer unit I needed a couple of washers to seat it properly. But a good result and my points cover is now attached.

I also fitted the speedo cable but sadly the speedo refuses to go over 10 mph so I need another one of those, I'll have to have a root around my boxes of bits.

Are you sure your bike goes over 10MPH!