BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: AdrianS on 24 Sep, 2020, 13:57

Title: Cylinder base nut size
Post by: AdrianS on 24 Sep, 2020, 13:57
Hi all
I need to get a new set of cylinder barrel base nuts for my early a50.
Struggling to find the size of them as I believe they changed over the years.
Can anyone let me know and also is there anything "special" about these nuts or can any of the correct size be used.
Cheers
Adrian
Title: Re: Cylinder base nut size
Post by: chaz on 24 Sep, 2020, 14:35
could be 5/16 BSC cycle 26tpi  24-5160
the later ones were 5/16 UNF 14-0302
the last ones were bigger 3/8 UNF and they were 12 point hexagon for easier undoing. 21-0692
Title: Re: Cylinder base nut size
Post by: AdrianS on 24 Sep, 2020, 17:04
Cheers
Do I need high tensile nuts or are standard nuts good enough?
£1.60 for a bag of 9 from Nookys or just under 50p each from Draganfly ( they don't specify spec)
Title: Re: Cylinder base nut size
Post by: chaz on 24 Sep, 2020, 20:21
standard are normally good enough, no washers involved.
remember Drags will buy a pack of 100 and have to sell them individually whether you want one or a set of 8 therefore they price individually to cover the bigger outlay, listing and storage. wouldnt even bother with stainless.
Title: Re: Cylinder base nut size
Post by: AdrianS on 24 Sep, 2020, 20:27
Will order from Nookys as need some other bits!
Title: Re: Cylinder base nut size
Post by: ChrisG on 26 Sep, 2020, 16:54
''the last ones were bigger 3/8 UNF and they were 12 point hexagon for easier undoing. 21-0692''

Yet all the parts lists including 1971 OIF models describe them as 5/16". I guess someone forgot to amend the lists when they did the design change and it stuck!