Author Topic: Very quick question about the SRM sprocket nut  (Read 902 times)

Offline BSA500

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what size is the srm gearbox sprocket nut. See told you it was quick :)

Online orabanda

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Re: Very quick question about the SRM sprocket nut
« Reply #1 on: 14.01. 2018 03:03 »
1"AF

Offline RoyC

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Re: Very quick question about the SRM sprocket nut
« Reply #2 on: 14.01. 2018 06:46 »
1"AF
And that was a quick answer,
My bike is a 1958 A7SS
Staffordshire UK

Offline BSA500

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Re: Very quick question about the SRM sprocket nut
« Reply #3 on: 14.01. 2018 15:21 »
Sorry should have been more specific, what size socket/box spanner do I need. My box spanner I have is 1 7/16 AF and wasn't big enough.

Online RichardL

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Re: Very quick question about the SRM sprocket nut
« Reply #4 on: 14.01. 2018 16:00 »
Uuh, I deleted my previous post when I realized you were probably are not talking about the cush nut.
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Online JulianS

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Re: Very quick question about the SRM sprocket nut
« Reply #5 on: 14.01. 2018 16:36 »
1 1/2 inch AF.

Offline BSA500

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Re: Very quick question about the SRM sprocket nut
« Reply #6 on: 14.01. 2018 17:37 »
Thank you. I did measure across the flats,but wasn't sure if AF means across the flats seems it does :)

Online Greybeard

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Re: Very quick question about the SRM sprocket nut
« Reply #7 on: 14.01. 2018 18:09 »
Thank you. I did measure across the flats,but wasn't sure if AF means across the flats seems it does :)
AF means American Fine but I believe the size refers to the distance across the flats.

Online JulianS

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Re: Very quick question about the SRM sprocket nut
« Reply #8 on: 14.01. 2018 18:58 »
I use a long ring spanner. Sockets not deep enough due to the mainshaft.

Online Rex

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Re: Very quick question about the SRM sprocket nut
« Reply #9 on: 14.01. 2018 21:23 »
AF means American Fine but I believe the size refers to the distance across the flats.

Errr...A/F means "across flats" .. ;)

Offline BSA500

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Re: Very quick question about the SRM sprocket nut
« Reply #10 on: 14.01. 2018 22:12 »
those spanners are expensive  *eek*

Online Greybeard

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Re: Very quick question about the SRM sprocket nut
« Reply #11 on: 14.01. 2018 22:38 »
AF means American Fine but I believe the size refers to the distance across the flats.

Errr...A/F means "across flats" .. ;)
Well, there I go talking utter ballcocks! I was introduced to the term American Fine when I was young and never had reason to doubt it until now. Thank you.  ::hh::

Online chaterlea25

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Re: Very quick question about the SRM sprocket nut
« Reply #12 on: 14.01. 2018 23:33 »
Hi All
Quote
those spanners are expensive  *eek*

Try Army Surplus stores or autojumbles, You can usually buy big sockets for small money
38mm is near enough 1.5in as makes no difference (0.1mm)
I have cut sockets and welded in extension pieces to access gearbox sprocket nuts *work*

John

1961 Super Rocket
1963 RGS (ongoing)

Offline duTch

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Re: Very quick question about the SRM sprocket nut
« Reply #13 on: 15.01. 2018 01:29 »

 maybe keep an eye out for a flogging spanner (one-ended ring spanner made for a hard life) ?
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online orabanda

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Re: Very quick question about the SRM sprocket nut
« Reply #14 on: 15.01. 2018 02:39 »
The spanner, or socket, should not be expensive.
The size of the hex is 1"Across the Flats (AF).

If your tool box includes a 1/2"drive electric or pneumatic rattle gun, all you need is the socket ($25 - $30).

A 1" combination or ring spanner will be $25 - $60, depending on brand; even the cheaper (asian) spanners are OK.

Pic of nut below:

Richard