Plug spanner size

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question on a
FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design would
allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

Jim

Dave Plowman (News)

2018-12-11 00:27:35 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

--
*I'm already visualizing the duct tape over your mouth

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.

Indy Jess John

2018-12-11 07:13:57 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

I confess that the socket I tested was hexagonal rather than the
customary 12-point ring, so it looked and felt a good fit. Perhaps a
traditional ring isn't as good.

I have an AF set of traditional rings in the garage. I will try those
later and let you know if I can get a match with those.

Jim

Dave Plowman (News)

2018-12-11 11:13:03 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

I confess that the socket I tested was hexagonal rather than the
customary 12-point ring, so it looked and felt a good fit. Perhaps a
traditional ring isn't as good.
I have an AF set of traditional rings in the garage. I will try those
later and let you know if I can get a match with those.

Getting closer, but you need to go back further than AF spanners. ;-)

--
*What happens when none of your bees wax? *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.

Indy Jess John

2018-12-11 12:37:18 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

I confess that the socket I tested was hexagonal rather than the
customary 12-point ring, so it looked and felt a good fit. Perhaps a
traditional ring isn't as good.
I have an AF set of traditional rings in the garage. I will try those
later and let you know if I can get a match with those.
Jim

I have now tested my AF spanner set. A proper fit with a proper ring
needs a 13/16 AF spanner.

(I don't think you can now find Whitworth ring spanners).

Jim

Dave Plowman (News)

2018-12-11 13:29:59 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

I confess that the socket I tested was hexagonal rather than the
customary 12-point ring, so it looked and felt a good fit. Perhaps a
traditional ring isn't as good.
I have an AF set of traditional rings in the garage. I will try those
later and let you know if I can get a match with those.
Jim

I have now tested my AF spanner set. A proper fit with a proper ring
needs a 13/16 AF spanner.
(I don't think you can now find Whitworth ring spanners).

They're probably still made somewhere. I've certainly got some, and
sockets too.

You are right, though. The nut size on a 14mm sparking plug is actually
7/16ths Whit (as marked on the spanner) About 20.8mm AF.

--
*IF YOU TRY TO FAIL, AND SUCCEED, WHICH HAVE YOU DONE?

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.

Indy Jess John

2018-12-11 17:50:54 UTC

Post by Dave Plowman (News)
Here's a question for classic car types. Which arose from a question
on a FB group. And I was surprised no one seemed to know.
You've lost your dedicated 14mm plug socket - but the engine design
would allow a ring spanner to be used.
What is the correct ring spanner size?

The standard spark plug (not the small ones some early Vauxhalls used)
is a 21mm ring spanner. I have just tried it.

21mm will sort of fit, but isn't the actual size.

I confess that the socket I tested was hexagonal rather than the
customary 12-point ring, so it looked and felt a good fit. Perhaps a
traditional ring isn't as good.
I have an AF set of traditional rings in the garage. I will try those
later and let you know if I can get a match with those.
Jim

I have now tested my AF spanner set. A proper fit with a proper ring
needs a 13/16 AF spanner.
(I don't think you can now find Whitworth ring spanners).

They're probably still made somewhere. I've certainly got some, and
sockets too.
You are right, though. The nut size on a 14mm sparking plug is actually
7/16ths Whit (as marked on the spanner) About 20.8mm AF.

You are right - they are still around, though many are used sets, eg
https://www.ebay.co.uk/itm/Set-of-6-vintage-Gordon-tools-whitworth-offset-ring-spanners-LOTWD7GRD/183578702095

Jim

Dave Plowman (News)

2018-12-12 00:53:42 UTC