I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of 6.93
for the 6 fixing holes in the metal plate which fixes to the wall. This
should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm) long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are man
enough that you just go down a size, or do I have the usual case where I
have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers



Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

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On 18/03/2017 14:28, David wrote:

M7, where are you?


A few on Ebay, though whether the pitch of the Thread is the same...

Seems M7 is used in split rim wheels, didn't know that

Sorry, scratch that, not in countersunk style there isn't

Bolts though

On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put through
them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

In article ,
David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of 6.93
for the 6 fixing holes in the metal plate which fixes to the wall. This
should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm) long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are man
enough that you just go down a size, or do I have the usual case where I
have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers

M7 is going to be difficult to find. But M6 will be more than up to the
job. CSK SS with an allen socket may look the best.

--
*Dance like nobody's watching.

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, 18 March 2017 15:12:04 UTC, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put through
them. 1/4" is 6.35, they should work.

For once she's right. Any woodscrew upto 6.9mm dia should fit.

7mm threaded holes does not mean M7, it means M8. 8mm is the outer diameter of an M8 bolt, not the inner, which is what your calipers are measuring.


NT

On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:

On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put through
them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for bolts
or screws.

Cheers



Dave R


--
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---
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On Sat, 18 Mar 2017 15:19:19 +0000, Dave Plowman (News) wrote:

In article ,
David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm)
long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are
man enough that you just go down a size, or do I have the usual case
where I have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers

M7 is going to be difficult to find. But M6 will be more than up to the
job. CSK SS with an allen socket may look the best.

Ta.

There seem to be plenty of M6 so I will go for some of those.

Still not sure why nobody seems to use M7.

Cheers


Dave R



--
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---
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On Saturday, 18 March 2017 17:39:33 UTC, David WE Roberts (Google) wrote:
On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put through
them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for bolts
or screws.

then I don't understand why you'd want M7. Something's not right with this picture.


NT

On 18/03/2017 14:28, David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of 6.93
for the 6 fixing holes in the metal plate which fixes to the wall. This
should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm) long,
with suitable nuts and washers. Stainless if at all possible.

Use M6. It's a telly not the QE2.

Bill

On 18/03/2017 17:41, David wrote:

Still not sure why nobody seems to use M7.

There's no demand for it because it isn't available.
It isn't available because there's no demand for it.

Bill

Bill Wright wrote:
On 18/03/2017 17:41, David wrote:

Still not sure why nobody seems to use M7.

There's no demand for it because it isn't available.
It isn't available because there's no demand for it.

Bill

It is quite popular in the motor trade M7 x 1.0 (same pitch as M6)
I got asked to make quite few car bits over the years and so bought a
set of taps and a split die for M7 (Iso-coarse).

Bob Minchin wrote:
Bill Wright wrote:
On 18/03/2017 17:41, David wrote:

Still not sure why nobody seems to use M7.

There's no demand for it because it isn't available.
It isn't available because there's no demand for it.

Bill

It is quite popular in the motor trade M7 x 1.0 (same pitch as M6)
I got asked to make quite few car bits over the years and so bought a
set of taps and a split die for M7 (Iso-coarse).
Hex head is normally M11 for these.

In article ,
David wrote:
M7 is going to be difficult to find. But M6 will be more than up to the
job. CSK SS with an allen socket may look the best.

Ta.

There seem to be plenty of M6 so I will go for some of those.

The important thing is how they sit in the countersink.

Still not sure why nobody seems to use M7.

Use two M3.5 electrical screws? ;-)

--
*I went to school to become a wit, only got halfway through.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
David wrote:
M7 is going to be difficult to find. But M6 will be more than up to the
job. CSK SS with an allen socket may look the best.

Ta.

There seem to be plenty of M6 so I will go for some of those.

The important thing is how they sit in the countersink.

Still not sure why nobody seems to use M7.

Use two M3.5 electrical screws? ;-)

Blimey Dave, you are up late. Fresh out of Brexit comments?

David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of 6.93
for the 6 fixing holes in the metal plate which fixes to the wall. This
should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm) long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are man
enough that you just go down a size, or do I have the usual case where I
have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers



Dave R

They are clearance holes for m6 screws or 1/4 screws

On Sat, 18 Mar 2017 10:50:39 -0700, tabbypurr wrote:

On Saturday, 18 March 2017 17:39:33 UTC, David WE Roberts (Google)
wrote:
On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in
the caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the
wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put
through them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for
bolts or screws.

then I don't understand why you'd want M7. Something's not right with
this picture.

I measured the hole to see what the size of bolt would be to match.

The dimensions suggest that you can fit an M7 bolt through the hole.

Biggest is usually best, especially when fixing heavy stuff with leverage
(bracket folds out from wall).

So I was opting for the chunkiest bolts I could fit through the hole.

Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sat, 18 Mar 2017 18:01:13 +0000, Bill Wright wrote:

On 18/03/2017 14:28, David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm)
long,
with suitable nuts and washers. Stainless if at all possible.

Use M6. It's a telly not the QE2.

Bill

The bracket is built like the QE2.

My main concern is the leverage when the bracket is fully extended with a
TV on the end. It folds out quite a long way.

Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 3/19/2017 12:03 PM, David wrote:
On Sat, 18 Mar 2017 10:50:39 -0700, tabbypurr wrote:

On Saturday, 18 March 2017 17:39:33 UTC, David WE Roberts (Google)
wrote:
On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in
the caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the
wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put
through them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for
bolts or screws.

then I don't understand why you'd want M7. Something's not right with
this picture.

I measured the hole to see what the size of bolt would be to match.

The dimensions suggest that you can fit an M7 bolt through the hole.

Biggest is usually best, especially when fixing heavy stuff with leverage
(bracket folds out from wall).

So I was opting for the chunkiest bolts I could fit through the hole.


Yes but these brackets are usually fixed to a masonry wall. This implies
wall plugs of some sort, and you can't fit these with perfect accuracy.
So having holes in the bracket which are slightly oversize to the screws
you use makes life very much easier. In any case, if fitted correctly
what stops the bracket moving around is not the lack of diametral
clearance between the bracket and the screws, but the friction between
the back of the bracket and the wall. You get the friction from the
tension in the screws. The bracket may be "resting" on one or two of the
screws, it's not likely to be resting on all of them (unless they are
countersunk).

ICBA to do the sums at the moment, but the shear strength of a single M6
bolt is something like a ton.

In article ,
David wrote:
Use M6. It's a telly not the QE2.

Bill

The bracket is built like the QE2.

My main concern is the leverage when the bracket is fully extended with a
TV on the end. It folds out quite a long way.

It is almost certainly designed for wall mounting using screws and wall
plugs. With these, the larger the better. So the plug doesn't pull out of
the bricks. But the chances of shearing an M6 nut and bolt, remote. The
fixing of the bracket to the 24" TV back here is 4 x M4.

I'd say your main problem in a caravan is finding something strong enough
to fix the bracket to - rather than the strength of the bolts.

--
*No word in the English language rhymes with month, orange, silver,purple

Dave Plowman London SW
To e-mail, change noise into sound.

On 3/18/2017 6:14 PM, Bob Minchin wrote:
Bill Wright wrote:
On 18/03/2017 17:41, David wrote:

Still not sure why nobody seems to use M7.

There's no demand for it because it isn't available.
It isn't available because there's no demand for it.

Bill

It is quite popular in the motor trade M7 x 1.0 (same pitch as M6)
I got asked to make quite few car bits over the years and so bought a
set of taps and a split die for M7 (Iso-coarse).

It's also a 7 mm af Allen key, isn't it? I recall having to buy one for
some VW brake callipers, iirc.

On 18/03/2017 14:28, David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of 6.93
for the 6 fixing holes in the metal plate which fixes to the wall. This
should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm) long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are man
enough that you just go down a size, or do I have the usual case where I
have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers



Dave R



You sure it is M7 .. and not another thread form
This is not far off 17/64 ... could it be an imperial thread, many items
made in Japan or US still use imperial sizes.

On 19/03/2017 12:11, David wrote:

Use M6. It's a telly not the QE2.

Bill

The bracket is built like the QE2.

My main concern is the leverage when the bracket is fully extended
with a
TV on the end. It folds out quite a long way.

You'd pull the wall down before you snapped two M6 bolts.

Bill

On 19/03/2017 12:11, David wrote:

Use M6. It's a telly not the QE2.

Bill

The bracket is built like the QE2.

My main concern is the leverage when the bracket is fully extended
with a
TV on the end. It folds out quite a long way.

You'd pull the wall down before you snapped two M6 bolts.

Bill

On Sun, 19 Mar 2017 20:49:49 +0000, rick wrote:

On 18/03/2017 14:28, David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm)
long,
with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are
man enough that you just go down a size, or do I have the usual case
where I have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers



Dave R



You sure it is M7 .. and not another thread form This is not far off
17/64 ... could it be an imperial thread, many items made in Japan or US
still use imperial sizes.

Hole isn't threaded.

Just trying to get a bolt/set screw with a snug fit.

Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
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On Sun, 19 Mar 2017 13:01:12 +0000, Dave Plowman (News) wrote:

In article ,
David wrote:
Use M6. It's a telly not the QE2.

Bill

The bracket is built like the QE2.

My main concern is the leverage when the bracket is fully extended with
a TV on the end. It folds out quite a long way.

It is almost certainly designed for wall mounting using screws and wall
plugs. With these, the larger the better. So the plug doesn't pull out
of the bricks. But the chances of shearing an M6 nut and bolt, remote.
The fixing of the bracket to the 24" TV back here is 4 x M4.

I'd say your main problem in a caravan is finding something strong
enough to fix the bracket to - rather than the strength of the bolts.

I did think that larger diameter bolts backed up by washers would spread
the load over a larger surface area and be more difficult to pull through
the wood panel.

For example an M1 bolt would probably pull straight out, M2 less so etc.

So going for the largest possible diameter of bolt seems sensible where
possible.

Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sun, 19 Mar 2017 12:25:48 +0000, newshound wrote:

On 3/19/2017 12:03 PM, David wrote:
On Sat, 18 Mar 2017 10:50:39 -0700, tabbypurr wrote:

On Saturday, 18 March 2017 17:39:33 UTC, David WE Roberts (Google)
wrote:
On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in
the caravan.

My (fairly) trusty electronic callipers give an internal diameter
of 6.93 for the 6 fixing holes in the metal plate which fixes to
the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put
through them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for
bolts or screws.

then I don't understand why you'd want M7. Something's not right with
this picture.

I measured the hole to see what the size of bolt would be to match.

The dimensions suggest that you can fit an M7 bolt through the hole.

Biggest is usually best, especially when fixing heavy stuff with
leverage (bracket folds out from wall).

So I was opting for the chunkiest bolts I could fit through the hole.


Yes but these brackets are usually fixed to a masonry wall. This implies
wall plugs of some sort, and you can't fit these with perfect accuracy.
So having holes in the bracket which are slightly oversize to the screws
you use makes life very much easier. In any case, if fitted correctly
what stops the bracket moving around is not the lack of diametral
clearance between the bracket and the screws, but the friction between
the back of the bracket and the wall. You get the friction from the
tension in the screws. The bracket may be "resting" on one or two of the
screws, it's not likely to be resting on all of them (unless they are
countersunk).

ICBA to do the sums at the moment, but the shear strength of a single M6
bolt is something like a ton.

Just to add to other responses, the holes in the bracket are counter sunk.

It isn't about the shear strength but about spreading the load around the
area of the nut on the back of the wood panel.

M6 looks O.K., but M7 would be nicer.
Just not a lot of it about.

Cheers



Dave R



--
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---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

In article ,
David wrote:
I'd say your main problem in a caravan is finding something strong
enough to fix the bracket to - rather than the strength of the bolts.

I did think that larger diameter bolts backed up by washers would spread
the load over a larger surface area and be more difficult to pull
through the wood panel.

For example an M1 bolt would probably pull straight out, M2 less so etc.

So going for the largest possible diameter of bolt seems sensible where
possible.

Would probably best to use something larger than washers to spread the
load. But at the end of the day the strength of the panel is the limiting
factor. Same as with a plasterboard wall, it would make more sense to fix
to the uprights etc that the panel is fixed to.

--
*There are 3 kinds of people: those who can count & those who can't.

Dave Plowman London SW
To e-mail, change noise into sound.

On 18 Mar 2017 17:41:04 GMT, David wrote:

Still not sure why nobody seems to use M7.

While M7 is standardised at three different pitches it's not a preferred size,
M3 M4 M5 M6 M8 M10 M12 etc are preferred sizes under ISO 262

The only place I've seen an M7 in widespread use is on the first motion shaft
extraction thread on a GM 1980's gearbox where you could remove the end cover
from the gearbox, remove a sheet metal cover plate underneath the clutch, press
the clutch pedal, clamp the clutch and cover plate to the flywheel with u-clips,
withdraw the first motion shaft, and unbolt the flywheel and clutch as one, drop
it through the hole in the bellhousing and thus change the clutch without
removing the gearbox / driveshafts etc. An easy 30 mins for a complete clutch
change vs three or four times that after they changed the design to a solid
bellhousing.

--

The Other Mike wrote:
On 18 Mar 2017 17:41:04 GMT, David wrote:

Still not sure why nobody seems to use M7.

While M7 is standardised at three different pitches it's not a preferred size,
M3 M4 M5 M6 M8 M10 M12 etc are preferred sizes under ISO 262

The only place I've seen an M7 in widespread use is on the first motion shaft
extraction thread on a GM 1980's gearbox where you could remove the end cover
from the gearbox, remove a sheet metal cover plate underneath the clutch, press
the clutch pedal, clamp the clutch and cover plate to the flywheel with u-clips,
withdraw the first motion shaft, and unbolt the flywheel and clutch as one, drop
it through the hole in the bellhousing and thus change the clutch without
removing the gearbox / driveshafts etc. An easy 30 mins for a complete clutch
change vs three or four times that after they changed the design to a solid
bellhousing.

I had one of those. Brilliant idea! no wonder it did not catch on.
I even made a 36mm x 1/2 square socket to remove the cover.
In order to get an M7 bolt for the job, there was one of several nearby
on the engine(bell housing?) that could be borrowed.

On 3/20/2017 8:47 AM, David wrote:
On Sun, 19 Mar 2017 12:25:48 +0000, newshound wrote:

On 3/19/2017 12:03 PM, David wrote:
On Sat, 18 Mar 2017 10:50:39 -0700, tabbypurr wrote:

On Saturday, 18 March 2017 17:39:33 UTC, David WE Roberts (Google)
wrote:
On Sat, 18 Mar 2017 15:12:01 +0000, Judith wrote:
On Sat, 18 Mar 2017 14:28:48 +0000, David wrote:

I'm getting ready to fix a TV bracket to a vertical wood panel in
the caravan.

My (fairly) trusty electronic callipers give an internal diameter
of 6.93 for the 6 fixing holes in the metal plate which fixes to
the wall.
This should make them M7.


If they are holes, it doesn't really matter what screw you put
through them. 1/4" is 6.35, they should work.


If they are threaded, then the internal diameter of 6.93 suggests (a
loose but tolerable fit for) 8mmx1.

Thanks - not threaded just a metal plate with counter sunk holes for
bolts or screws.

then I don't understand why you'd want M7. Something's not right with
this picture.

I measured the hole to see what the size of bolt would be to match.

The dimensions suggest that you can fit an M7 bolt through the hole.

Biggest is usually best, especially when fixing heavy stuff with
leverage (bracket folds out from wall).

So I was opting for the chunkiest bolts I could fit through the hole.


Yes but these brackets are usually fixed to a masonry wall. This implies
wall plugs of some sort, and you can't fit these with perfect accuracy.
So having holes in the bracket which are slightly oversize to the screws
you use makes life very much easier. In any case, if fitted correctly
what stops the bracket moving around is not the lack of diametral
clearance between the bracket and the screws, but the friction between
the back of the bracket and the wall. You get the friction from the
tension in the screws. The bracket may be "resting" on one or two of the
screws, it's not likely to be resting on all of them (unless they are
countersunk).

ICBA to do the sums at the moment, but the shear strength of a single M6
bolt is something like a ton.

Just to add to other responses, the holes in the bracket are counter sunk.

It isn't about the shear strength but about spreading the load around the
area of the nut on the back of the wood panel.

Penny washer!

In article ,
Bob Minchin wrote:
The Other Mike wrote:
On 18 Mar 2017 17:41:04 GMT, David wrote:

Still not sure why nobody seems to use M7.

While M7 is standardised at three different pitches it's not a
preferred size, M3 M4 M5 M6 M8 M10 M12 etc are preferred sizes under
ISO 262

The only place I've seen an M7 in widespread use is on the first
motion shaft extraction thread on a GM 1980's gearbox where you could
remove the end cover from the gearbox, remove a sheet metal cover
plate underneath the clutch, press the clutch pedal, clamp the clutch
and cover plate to the flywheel with u-clips, withdraw the first
motion shaft, and unbolt the flywheel and clutch as one, drop it
through the hole in the bellhousing and thus change the clutch without
removing the gearbox / driveshafts etc. An easy 30 mins for a
complete clutch change vs three or four times that after they changed
the design to a solid bellhousing.

I had one of those. Brilliant idea! no wonder it did not catch on. I
even made a 36mm x 1/2 square socket to remove the cover. In order to
get an M7 bolt for the job, there was one of several nearby on the
engine(bell housing?) that could be borrowed.

It certainly sounds a good idea - and I've never heard of it before. But
do wonder how much effect having a hole in the bell housing large enough
to remove the clutch would have on engine/box rigidity?

--
*Letting a cat out of the bag is easier than putting it back in *

Dave Plowman London SW
To e-mail, change noise into sound.

On 20/03/2017 08:47, David wrote:

Just to add to other responses, the holes in the bracket are counter sunk.

It isn't about the shear strength but about spreading the load around the
area of the nut on the back of the wood panel.

M6 looks O.K., but M7 would be nicer.
Just not a lot of it about.

Drill it out to 8mm?

In article om, F Murtz
wrote:
David wrote:
I'm getting ready to fix a TV bracket to a vertical wood panel in the
caravan.

My (fairly) trusty electronic callipers give an internal diameter of
6.93 for the 6 fixing holes in the metal plate which fixes to the wall.
This should make them M7.

What I need is 6 countersunk machine screws 25mm (or possibly 30mm)
long, with suitable nuts and washers. Stainless if at all possible.

I thought a domed nut would probably be the smartest.

For some reason the online stores I have looked at so far don't seem to
stock M7. After M6 they seem to go up in even numbers only.

Is this because once you get to a certain size the machine screws are
man enough that you just go down a size, or do I have the usual case
where I have assumed that fixings will be available but they aren't?

M7, where are you?

Cheers



Dave R

They are clearance holes for m6 screws or 1/4 screws

or for something American

--
from KT24 in Surrey, England