I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

I'd prefer the figures for metric screws (i.e. diameters in mm) and in
Nm but I'm quite happy to convert if necessary. The actual screws I'm
using are ScrewFix TurboGold and the stainless steel versions of the
same. I would guess however that most good quality screws are going
to be similar, I'm not after accurate figures, just an idea of what
is likely to break them.

--
Chris Green

wrote:
I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

Actually, it pretty much is tensile strength.
Steel (of any sort) pretty much has a constant stiffness.
If you stretch it a given amount, it'll stretch a certain distance.

If you think about what's happening in the screw, if you draw lines along
the shank of the screw, when you turn it, it gets twisted into a spiral.
As each line is now longer, that means that it's under tension on the
outside, and the inside is under compression.
At some point the force just gets too high, and the screw either tears,
snaps or bends.

IMO, this figure is utterly irrelevant in most cases, it's hard to
get most types of screwdriver bit to exert enough force on the screw
to get it to fail this way.
And if you could, it's not relevant as by the time you've reached that
number, in nearly all cases the screw has gone too deep.

IMO, this figure is utterly irrelevant in most cases, it's hard to
get most types of screwdriver bit to exert enough force on the screw
to get it to fail this way.
And if you could, it's not relevant as by the time you've reached that
number, in nearly all cases the screw has gone too deep.

I managed to shear off the head of a dry-wall screw last week with a normal
screwdriver! (just wouldnt go in that fraction more I wanted, ended up using
a nail in that spot )

wrote in message ...
I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

I'd prefer the figures for metric screws (i.e. diameters in mm) and in
Nm but I'm quite happy to convert if necessary. The actual screws I'm
using are ScrewFix TurboGold and the stainless steel versions of the
same. I would guess however that most good quality screws are going
to be similar, I'm not after accurate figures, just an idea of what
is likely to break them.

--
Chris Green
Get a torque wrench and "break" a few. You will soon get what you want
easier than asking such a rediculous question,

In article ,
Ian Stirling wrote:
IMO, this figure is utterly irrelevant in most cases, it's hard to
get most types of screwdriver bit to exert enough force on the screw
to get it to fail this way.
And if you could, it's not relevant as by the time you've reached that
number, in nearly all cases the screw has gone too deep.

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

--
*Never put off until tomorrow what you can avoid altogether *

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

a wrote:
IMO, this figure is utterly irrelevant in most cases, it's hard to
get most types of screwdriver bit to exert enough force on the screw
to get it to fail this way.
And if you could, it's not relevant as by the time you've reached that
number, in nearly all cases the screw has gone too deep.

I managed to shear off the head of a dry-wall screw last week with a normal
screwdriver! (just wouldnt go in that fraction more I wanted, ended up using
a nail in that spot )

Well, you can get screws made of alloys with the tensile strength of
extra-mature cheddar...

Dave Plowman (News) wrote:

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

I've broken quite a few Torx screws (SpaX) with my 18V combi, including
some very large ones (150mm size 8).

--
Grunff

I've broken quite a few Torx screws (SpaX) with my 18V combi, including
some very large ones (150mm size 8).

Ooer - a competition...

I`ve sheared 12mm bolts before now - not the monkey metal kind :-}

--
Please add "[newsgroup]" in the subject of any personal replies via email
--- My new email address has "ngspamtrap" & @btinternet.com in it ;-) ---

Jim wrote:

[snip]

Get a torque wrench and "break" a few. You will soon get what you want
easier than asking such a rediculous question,

Is there such a thing as a ridculous question? I thought it was only
ridiculous answers?

Ian Stirling wrote:
wrote:
I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

Actually, it pretty much is tensile strength.
Steel (of any sort) pretty much has a constant stiffness.
If you stretch it a given amount, it'll stretch a certain distance.

If you think about what's happening in the screw, if you draw lines along
the shank of the screw, when you turn it, it gets twisted into a spiral.
As each line is now longer, that means that it's under tension on the
outside, and the inside is under compression.
At some point the force just gets too high, and the screw either tears,
snaps or bends.

IMO, this figure is utterly irrelevant in most cases, it's hard to
get most types of screwdriver bit to exert enough force on the screw
to get it to fail this way.
And if you could, it's not relevant as by the time you've reached that
number, in nearly all cases the screw has gone too deep.

Yes I *did* realise there would be a fairly direct relation to tensile
strength but that doesn't directly help me work out the 'torque
strength'.

Anyway it is quite easy to break Pozidriv screws in my experience and
I also use some hex head coach screws where you can apply effectively
unlimited torque.

--
Chris Green

wrote in :

I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them.

Ask the buggers who fitted my double glazing

mike

Jim (remove $ ) wrote:

wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

I'd prefer the figures for metric screws (i.e. diameters in mm) and in
Nm but I'm quite happy to convert if necessary. The actual screws I'm
using are ScrewFix TurboGold and the stainless steel versions of the
same. I would guess however that most good quality screws are going
to be similar, I'm not after accurate figures, just an idea of what
is likely to break them.

Get a torque wrench and "break" a few. You will soon get what you want
easier than asking such a rediculous question,

Well I may need to do that ultimately, I do have a torque wrench and
it would be easy enough to try it with one of the hex head coach
screws. However I would have thought that at least some of the better
screw manufacturers would publish such figures.

--
Chris Green

However I would have thought that at least some of the better
screw manufacturers would publish such figures.


Well, for "high tensile" bolts you can usually work out the values from the
numbers stamped on the heads. But then, you might want to know the strength of
the bolts if (say) you were using six of them to hold a 2 inch flange on a 100
psi system. But you are not usually doing stress analysis on wooden structures
held together with screws. Why were you asking? Find a friendly metallurgy lab
and you might get them to measure the hardness for a particular type of screw,
then there are formulae. Usually what you want in carpentry is a joint that is
as strong in shear as the wood. You don't need much area of the weakest steel
to get enough normal force across the joint; friction and/or glue do the rest.

OldScrawn wrote:
However I would have thought that at least some of the better
screw manufacturers would publish such figures.


Well, for "high tensile" bolts you can usually work out the values from the
numbers stamped on the heads. But then, you might want to know the strength of
the bolts if (say) you were using six of them to hold a 2 inch flange on a 100
psi system. But you are not usually doing stress analysis on wooden structures
held together with screws. Why were you asking? Find a friendly metallurgy lab
and you might get them to measure the hardness for a particular type of screw,
then there are formulae. Usually what you want in carpentry is a joint that is
as strong in shear as the wood. You don't need much area of the weakest steel
to get enough normal force across the joint; friction and/or glue do the rest.

As I was trying to explain in my original question I'm not in the
slightest bit interested (well, not for this question anyway) what the
*tensile* strength of screws is. So it's not about how well they hold
things together.

What I'm after is how easy it is to break them, especially with a
power screwdriver.

--
Chris Green

wrote:
What I'm after is how easy it is to break them, especially with a
power screwdriver.
http://www.grkfasteners.com/selection_guide.htm

Any good?

Regards
Capitol

wrote:
OldScrawn wrote:
However I would have thought that at least some of the better
screw manufacturers would publish such figures.


Well, for "high tensile" bolts you can usually work out the values
from the numbers stamped on the heads. But then, you might want to
know the strength of the bolts if (say) you were using six of them
to hold a 2 inch flange on a 100 psi system. But you are not usually
doing stress analysis on wooden structures held together with
screws. Why were you asking? Find a friendly metallurgy lab and you
might get them to measure the hardness for a particular type of
screw, then there are formulae. Usually what you want in carpentry
is a joint that is as strong in shear as the wood. You don't need
much area of the weakest steel to get enough normal force across the
joint; friction and/or glue do the rest.

As I was trying to explain in my original question I'm not in the
slightest bit interested (well, not for this question anyway) what the
*tensile* strength of screws is. So it's not about how well they hold
things together.

What I'm after is how easy it is to break them, especially with a
power screwdriver.

BUT WHY????? If it is so you don't break any during 'installation' turn your
torque ring down so the screw is proud and then increase it till it's flush!
Nobody on here seems to know the answer to a question that seems
irrelevant!!

John

Capitol wrote:


wrote:
What I'm after is how easy it is to break them, especially with a
power screwdriver.
http://www.grkfasteners.com/selection_guide.htm

Any good?

Nearly, it tells one everything one could possible want to know about
the screws except how easy (or otherwise) it is to break them when
screwing them in. It doesn't even seem to tell you how tightly you
ought to screw them in to get the figures for fixing strength they
give.

--
Chris Green

John wrote:
wrote:
OldScrawn wrote:
However I would have thought that at least some of the better
screw manufacturers would publish such figures.


Well, for "high tensile" bolts you can usually work out the values
from the numbers stamped on the heads. But then, you might want to
know the strength of the bolts if (say) you were using six of them
to hold a 2 inch flange on a 100 psi system. But you are not usually
doing stress analysis on wooden structures held together with
screws. Why were you asking? Find a friendly metallurgy lab and you
might get them to measure the hardness for a particular type of
screw, then there are formulae. Usually what you want in carpentry
is a joint that is as strong in shear as the wood. You don't need
much area of the weakest steel to get enough normal force across the
joint; friction and/or glue do the rest.

As I was trying to explain in my original question I'm not in the
slightest bit interested (well, not for this question anyway) what the
*tensile* strength of screws is. So it's not about how well they hold
things together.

What I'm after is how easy it is to break them, especially with a
power screwdriver.

BUT WHY????? If it is so you don't break any during 'installation' turn your
torque ring down so the screw is proud and then increase it till it's flush!
Nobody on here seems to know the answer to a question that seems
irrelevant!!

Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.

--
Chris Green

On 30 Oct 2004 11:35:26 GMT, wrote:



Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.

I think that it's going to be a tough one to work out.

If it was threaded components going into metal, then it's rather
easier because you are trying to avoid distorting something, stripping
threads or shearing the stud/bolt and the materials are reasonably
predictable.

For screwing into wood, there are a whole bunch of variables:

- The species and to some extent moisture content of the wood.

- The type of screw - e.g. standard, double threaded, serrated edge
etc.

- Size and depth of pilot hole if any.

- The type of screwdriver

- Whether lubrication is used


For example, at one end of the spectrum, I have a Senco collated
screwdriver which takes screws on a plastic band. Typically they are
3 or 4mm types with a square slot head. It's really fast for
panelling and drywalling work and will comfortably drive the screws
through ply or plasterboard into constructional softwood.

At the other end, I was rehanging an oak door into an oak frame today
because I needed to reverse the opening side of the door.
Since oak contains tannins which eventually corrode steel as well as
for aesthetic reasons I wanted to use brass screws.
However, brass will not stand up to high torque driving (it will shear
or the screwdriver cams out) and oak is tough material, so to achieve
this, I drilled carefully sized pilot holes and put in normal Spax
screws to cut a thread. Then I removed the steel screws and put in
the brass ones easily.

I used stainless steel screws in aspects of my cabin construction and
found that these had a tendency to shear unless there was a reasonable
pilot hole.

Some of the Spax and Turbogold etc. screws are claimed to be able to
be driven into wood without a pilot hole. I've found this to be
moderately true into softwood as long as it's away from an edge or end
and one isn't looking for a particularly good finish. Trying this
with hardwood, doesn't seem to work. Either the screw shears or cams
out, and there is a mess.

For applications using the larger sizes of Spax screw, I tend to pick
the pilot hole drill carefully and then using a combined drill
countersink, drill to the correct depth. Occasionally with larger
ones, a touch of some lubricant (e.g. candlewax) on the threads
helps.

So in terms of the torque needed to drive the screw, I think it would
be pretty hard to determine that because there are too many variables
with wood. If the concern is over having too much torque and
shearing the screw, then I would say that if it happens, the pilot
hole arrangement was not right or if shearing happens when the screw
is fully home, the clutch setting needs to be reduced.



--

..andy

To email, substitute .nospam with .gl

wrote in message ...
John wrote:
wrote:
snip

BUT WHY????? If it is so you don't break any during 'installation' turn
your
torque ring down so the screw is proud and then increase it till it's
flush!
Nobody on here seems to know the answer to a question that seems
irrelevant!!

Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.


I see where you're coming from, but I'm not entirely sure that it has any
relevance other than purely academic or theoretical. It's an interesting
question, though, and I'm surprised that ability to withstand up to X amount
of torque isn't somewhere within screw specifications. Perhaps your best
bet is to hunt down and contact the manufacturers of the particular screws
that you're using - I don't really see that you can work out shear strength
for a particular size of screw in general because they're all going to be
made from slightly different materials and to slightly different
specifications, which could have a disproportionately large effect on the
shear strength.

All the manufacturers of Industrial-rated tools seem to give two figures for
maximum torque - one for "soft" joints and one for "hard" joints - anyone
have a clue what the difference is here, and whether there is actually a
standardised test for measuring these?

As for buying a drill/driver, I think that the thing is to go for as high a
torque as you can find for a particular voltage & price point - it will
indicate better cells and motor. 20 or so step torque control is pretty
much essential. Then just play about until you get the ideal maximum torque
setting for a particular screw in whatever it's going into. Even if you
expect to be driving only no.8 screws in normal use, you can always use the
torque control to reduce the torque, but you can't turn up a less powerful
drill if you have the need to drive in occasional long no.12s for instance.

Incidentally, you ought not to get close to shearing a screw in an ideal
situation - received wisdom in the woodworking community appears to be that
maximum holding strength from a screw is achieved when a pilot hole of the
_correct size_ is drilled first. It's pretty much essential when using
brass screws, but an often skipped step with stronger screws that can be
driven directly into the material with a modern driver.



--
Richard Sampson

mail me at
richard at olifant d-ot co do-t uk

In article ,
wrote:
Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.

Well, all these sort of things have adjustable maximum torque. And on mine
the minimum setting is so low I've never used it.

But I think you're worrying far too much. As I've said, I frequently use a
mains drill as a screwdriver, and it has much more torque than any normal
cordless. This would often be for screwing down floorboards - lots and
lots of 2" 10 pozidriv. And breaking a screw is a rarity. The bit 'cams
out' before this happens.

--
*TEAMWORK...means never having to take all the blame yourself *

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

RichardS noone@invalid wrote:
wrote in message ...
John wrote:
wrote:
snip

BUT WHY????? If it is so you don't break any during 'installation' turn
your
torque ring down so the screw is proud and then increase it till it's
flush!
Nobody on here seems to know the answer to a question that seems
irrelevant!!

Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.


I see where you're coming from, but I'm not entirely sure that it has any
relevance other than purely academic or theoretical. It's an interesting
question, though, and I'm surprised that ability to withstand up to X amount
of torque isn't somewhere within screw specifications. Perhaps your best
bet is to hunt down and contact the manufacturers of the particular screws
that you're using - I don't really see that you can work out shear strength
for a particular size of screw in general because they're all going to be
made from slightly different materials and to slightly different
specifications, which could have a disproportionately large effect on the
shear strength.

I wouldn't have thought that different types of steel would have huge
effects. I'm not interested in exact figure. I just want to know if
(for example) a 5mm screw will shear at 10nM or a 100nM. OK,
different steel screws might well have a shear torque ranging from 15
to 50nM but even that sort of range gives me an idea.


All the manufacturers of Industrial-rated tools seem to give two figures for
maximum torque - one for "soft" joints and one for "hard" joints - anyone
have a clue what the difference is here, and whether there is actually a
standardised test for measuring these?

I think 'soft' and 'hard' is just the torque in the high gear and the
low gear of their two speed gearboxes isn't it? Why on earth they're
called 'soft' and 'hard' I don't know.


As for buying a drill/driver, I think that the thing is to go for as high a
torque as you can find for a particular voltage & price point - it will
indicate better cells and motor. 20 or so step torque control is pretty
much essential. Then just play about until you get the ideal maximum torque
setting for a particular screw in whatever it's going into. Even if you
expect to be driving only no.8 screws in normal use, you can always use the
torque control to reduce the torque, but you can't turn up a less powerful
drill if you have the need to drive in occasional long no.12s for instance.

As I've just reported in my original thread asking about cordless
drivers I've bought a Metabo SBT12 which produces a maximum torque of
53Nm. I've just used it for the first time and I'm impressed. It
screwed the 8mm x 100mm Turbogold screws into fence posts (the
application I specifically wanted it for) effortlessly - excellent!

Incidentally, you ought not to get close to shearing a screw in an ideal
situation - received wisdom in the woodworking community appears to be that
maximum holding strength from a screw is achieved when a pilot hole of the
_correct size_ is drilled first. It's pretty much essential when using
brass screws, but an often skipped step with stronger screws that can be
driven directly into the material with a modern driver.

I don't drill pilot holes purely to save time, I'm not aiming for
beauty when screwing fences together. I use screws rather than nails
simply because it eases taking them apart if it's ever necessary and
because it's stronger, nails pull out (especially if half a ton of
horse leans on the other side).

--
Chris Green

"Dave Plowman (News)" wrote:
In article ,
wrote:
Well it's really to find out how much torque is needed to screw them
in successfully and how much will break them. I'm looking for a new
cordless driver and want to know what sort of torque figure is useful
and how much is simply too much. The cordless driver specifications
give their maximum torquer but nowhere can I find any figures for how
much torque is actually needed to screw screws in.

Well, all these sort of things have adjustable maximum torque. And on mine
the minimum setting is so low I've never used it.

But I think you're worrying far too much. As I've said, I frequently use a
mains drill as a screwdriver, and it has much more torque than any normal
cordless. This would often be for screwing down floorboards - lots and
lots of 2" 10 pozidriv. And breaking a screw is a rarity. The bit 'cams
out' before this happens.

I'm screwing in 8mm hex head coach screws, nothing 'comes out' in this
case, you have several alternative options:-

The driver runs out of oomph, the usual case until I got my new
Metabo SBT12. I then had to use a spanner to get the screw in the
rest of the way.

The cordless clutch/torque setting starts to slip, this is what
happens on the stiffest setting on the Metabo. It does get the
screw in most of the way before it starts clicking though.

I stop screwing when the screw reaches the right point, generally
possible and this is what I'm doing.

The screw shears if/when I don't stop in time. It hasn't happened
yet with the new Metabo but it would be nice to know if 53Nm is
capable of shearing an 8mm screw.

--
Chris Green

wrote in message ...
snip

The screw shears if/when I don't stop in time. It hasn't happened
yet with the new Metabo but it would be nice to know if 53Nm is
capable of shearing an 8mm screw.


If it's so important why not contact the screw manufactures tech' dept. and
ask them rather than ask a load of (mainly) DIY armatures ?!...

":::Jerry::::" wrote in message
...

wrote in message ...
snip

The screw shears if/when I don't stop in time. It hasn't happened
yet with the new Metabo but it would be nice to know if 53Nm is
capable of shearing an 8mm screw.


If it's so important why not contact the screw manufactures tech' dept.
and
ask them rather than ask a load of (mainly) DIY armatures ?!...

Try Timberloks. Great screws and new replacement for 12mm bolts.

In article ,
:::Jerry:::: wrote:
rather than ask a load of (mainly) DIY armatures ?!...

Are you 'winding' us up?

--
*The severity of the itch is proportional to the reach *

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

"Dave Plowman (News)" wrote in message
...
In article ,
:::Jerry:::: wrote:
rather than ask a load of (mainly) DIY armatures ?!...

Are you 'winding' us up?


And just how many metallurgist are there contributing to this group ?..

On Sun, 31 Oct 2004 10:55:22 UTC, ":::Jerry::::" wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
:::Jerry:::: wrote:
rather than ask a load of (mainly) DIY armatures ?!...

Are you 'winding' us up?


And just how many metallurgist are there contributing to this group ?..

Oh dear....M.T.P.....


--
The information contained in this post
is copyright (C) RD Eager, 2004, and
may not be published in, or used by
http://www.diyprojects.info, who are
FORBIDDEN from copying it.

"Bob Eager" wrote in message
...
On Sun, 31 Oct 2004 10:55:22 UTC, ":::Jerry::::" wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
:::Jerry:::: wrote:
rather than ask a load of (mainly) DIY armatures ?!...

Are you 'winding' us up?


And just how many metallurgist are there contributing to this group ?..

Oh dear....M.T.P.....


Yeh, and you're a T.W.A.T...

In article ,
:::Jerry:::: wrote:
rather than ask a load of (mainly) DIY armatures ?!...

Are you 'winding' us up?


And just how many metallurgist are there contributing to this group ?..

Err, joke about armature rather than amateur. You've got to watch what
the spoolcheeker does. Well, I have to anyway. If I remember.

But I could ask my niece. Or her husband. Wonder how many others have
two metallurgists in the family?

--
*I speak fluent patriarchy but it's not my mother tongue

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

On Fri, 29 Oct 2004 11:25:07 +0000, usene wrote:

I'd like to have some 'ball park' figures for the torque which typical
wood screws can handle. Can anyone give me some typical figures or
point me at a web site that has them? I would emphasise that I'm
after the torque figure, i.e. the amount of twist needed to break
them. I realise this doesn't directly relate to the strength of the
screw holding things together which would simply be given by the
tensile stregth of the screw.

I'd prefer the figures for metric screws (i.e. diameters in mm) and in
Nm but I'm quite happy to convert if necessary. The actual screws I'm
using are ScrewFix TurboGold and the stainless steel versions of the
same. I would guess however that most good quality screws are going
to be similar, I'm not after accurate figures, just an idea of what
is likely to break them.

In my experience it is much more easy to over cook 4mm screws by
forgetting to reduce the torque setting then it is to break them.
In fact the only way in my experience is not drill a masonry hole
deep enough and then to get a really good screw/hole/plug combination.

I would reckon that you would never break a 4mm screw on the high speed
setting (you'd stall the motor first). A typical pro quality 12v cordless
is rated at about 20Nm. The high speed would typically be around 6Nm.

So I guess the ball park to break a 4mm gold screw is the better part of
20 Nm. I would reckon that it is nigh on impossible to get that tightness
into softwood only hardwood or a blind masonry hole.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

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On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.


NT

On 06/01/16 17:34, wrote:
On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.


NT

I've lost count of how many I've snapped.
Mainlyt te smaller shafts - is it No 4?

But I've snapped car studs of a lot bigger diameter than that


--
Bureaucracy defends the status quo long past the time the quo has lost
its status.

Laurence Peter

In article ,
The Natural Philosopher wrote:
On 06/01/16 17:34, wrote:
On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.


NT

I've lost count of how many I've snapped.
Mainlyt te smaller shafts - is it No 4?

But I've snapped car studs of a lot bigger diameter than that

Back in the early 70s, I snapped a 5" no 14 - only using a handbrace. The
screws cost 14/- each, too. Shows how much I was upset - I can still
remember it.

--
Please note new email address:

On Wed, 06 Jan 2016 17:34:10 -0000, wrote:

On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.

All drills I've ever seen have an "accelerator pedal". Does your 2.5 litre car always go 150mph without control? You don't pull the lever all the way in when screwing!

--
In the UK, 90% of things are prohibited. The other 10% are compulsory.

On 06/01/2016 18:02, Mr Macaw wrote:
On Wed, 06 Jan 2016 17:34:10 -0000, wrote:

On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm
screwfix black plasterboard screws with Philips no2 heads.

All drills I've ever seen have an "accelerator pedal". Does your 2.5
litre car always go 150mph without control? You don't pull the lever
all the way in when screwing!

Is that what she said last night? ;-)

--
Bod

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

On Wed, 06 Jan 2016 18:16:30 -0000, Bod wrote:

On 06/01/2016 18:02, Mr Macaw wrote:
On Wed, 06 Jan 2016 17:34:10 -0000, wrote:

On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm
screwfix black plasterboard screws with Philips no2 heads.

All drills I've ever seen have an "accelerator pedal". Does your 2.5
litre car always go 150mph without control? You don't pull the lever
all the way in when screwing!

Is that what she said last night? ;-)

Some women can't take my 9 inch driver.

--
Hickory dickory dock, three mice ran up the clock. The clock struck one, and the others got away with minor injuries.

On Wednesday, 6 January 2016 18:02:30 UTC, Mr Macaw wrote:
On Wed, 06 Jan 2016 17:34:10 -0000, tabbypurr wrote:
On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.

All drills I've ever seen have an "accelerator pedal". Does your 2.5 litre car always go 150mph without control? You don't pull the lever all the way in when screwing!

We don't need reminding of your cluelessness

On Wed, 06 Jan 2016 20:15:41 -0000, wrote:

On Wednesday, 6 January 2016 18:02:30 UTC, Mr Macaw wrote:
On Wed, 06 Jan 2016 17:34:10 -0000, tabbypurr wrote:
On Friday, 29 October 2004 16:47:50 UTC+1, Dave Plowman (News) wrote:
In article ,

Yup. I often use my mains drill for screwdriving and it's got much more
torque than most cordless ones and no clutch.
A screw breaking is a rare event - they usually 'cam out' first with
Pozidriv

When I used to do that I snapped a fair few. They were mostly 32mm screwfix black plasterboard screws with Philips no2 heads.

All drills I've ever seen have an "accelerator pedal". Does your 2.5 litre car always go 150mph without control? You don't pull the lever all the way in when screwing!

We don't need reminding of your cluelessness

It's not me that breaks screws. I know how to use a drill correctly.

--
Peter is now listening to "Guo Yi & Guo Yue - Mongolian Horse"