Screws - advantages and disadvantages of the various types
ch...@areti.co.uk
be worth asking here about the advantages and disadvantages of the
various types. The descriptions on the various web sites (ScrewFix
and others) don't tell one much about the *comparitive* merits of the
different styles.
My main use is basic joinery, mostly with 'real' wood but also with
plywood and chipboard. I'd prefer a universal screw that I can use in
all material types. Cost is not hugely significant as the screws very
rarely cost a significant amount compared with other materials.
I want PoziDriv (or equivalent) heads, there's no question they are
easiest to use in my opinion and they look OK too.
So, the choice is then down to:-
Good quality, metric, 'gold' screws like ScrewFix TurboGold, these
are what I use at the moment. They seem pretty good generally but
I do occasionally break one.
Next step down gold metric, (e.g. ScrewFix Goldscrews) presumably
no advantage except that of being a bit cheaper. I did find (when
I used these) that they were fairly easy to break.
Silver colour twin thread screws (e.g. Screwfic Quicksilver R
Twinthread). I don't know much about these as I migrated from
old-fashioned steel slotted screws straight to the metric 'gold'
screws.
Stainless Steel screws, are these as strong as the best of the
others above? Will they really show big advantages when used out
of doors? Are they as good as non-stainless screws for ease of
driving etc.?
What I'm really after knowing is whether I would notice any big
differences by moving from the TurboGold screws to either Zinc plated
(i.e. silver coloured) ones or to stainless steel. I do a fair amount
of work out of doors so stainless does have some attractions but would
I lose out in other ways (strength, ease of driving, etc.) if I used
them? Are 'silver' screws as corrosion resistant as the gold ones?
Do the twin thread silver screws drive more easily or less easily? Are
the silver screws stronger or weaker or neither?
I don't *have* to order from ScrewFix either but, given that there are
probably only very few actual screw manufacturers I suspect one gets
the same screws regardless of supplier.
--
Chris Green (cgr...@x-1.net)
Grunff
<ch...@areti.co.uk> wrote in message
news:grtM7.20269$k55.4...@monolith.news.easynet.net...
> I'm looking at restocking my supplies of screws and thought it might
> be worth asking here about the advantages and disadvantages of the
> various types. The descriptions on the various web sites (ScrewFix
> and others) don't tell one much about the *comparitive* merits of the
> different styles.
>
> My main use is basic joinery, mostly with 'real' wood but also with
> plywood and chipboard. I'd prefer a universal screw that I can use in
> all material types. Cost is not hugely significant as the screws very
> rarely cost a significant amount compared with other materials.
>
> I want PoziDriv (or equivalent) heads, there's no question they are
> easiest to use in my opinion and they look OK too.
I used to favour Pozi, until I tried Screwfix's new Torx head wood screws.
No skipping - ever! I love those screws. Quite expensive, but as you say,
the cost of the screws is minor in the overall equation.
Grunff
Andy Hall
>
> So, the choice is then down to:-
>
> Good quality, metric, 'gold' screws like ScrewFix TurboGold, these
> are what I use at the moment. They seem pretty good generally but
> I do occasionally break one.
Do you mean you manage to shear them off while driving them? Near the head
or part way down?
I guess I've broken a couple of the No. 8 equivalents but that was really
because I hadn't drilled the pilot hole deeply enough I think. I was also
using an angle drill which seems to have quite a torque so perhaps that
contributed as well.
.andy
andrewpreece
They are expensive though. I have never broken one yet although I have
managed to
round out the posidrive head on a few ( probably needed a bit of vaseline
going in ? ), so am interested in this Torex socket head that's mentioned. I
take the
view that they won't weep rusty stains all over the wood and they'll be easy
to remove in future if I need to modify/move stuff. I had to drill out
plenty of old
bright steel screws ( totally corroded after 15 years ) from the garden
gate I was dismantling and didn't enjoy that at all. I don't have any
comparative
long-term info on the corrosion resistance of
zinc-plated/passivated/stainless fasteners though.....
Andy
<ch...@areti.co.uk> wrote in message
news:grtM7.20269$k55.4...@monolith.news.easynet.net...
Dave Liquorice
> Stainless Steel screws, are these as strong as the best of the
> others above? Will they really show big advantages when used out
> of doors?
Well they won't rust, ever. (asuming a decent grade of stainless
steel). All the others you mention will and possibly quite quickly
depending on the conditions and the quality of the zincification, hop
dip galvanised is the only real way to protect steel outside.
> Are they as good as non-stainless screws for ease of driving etc.?
Donno. Stainless is pretty tough stuff, difficult to machine but I
don't know if that makes if more or less brittle than steel.
I tend to use brass outside if I'm not worried about the staining.
Brass is rather soft though and in hardwoods needs the hole precutting
with a steel screw before you put in the brass one.
--
Cheers new...@howhill.com
Dave. Remove "spam" for valid email.
Grunff
"andrewpreece" <andrew...@onetel.net.uk> wrote in message
news:3c02...@212.67.96.135...
> I have used stainless steel exclusively on my outdoor projects this year.
> They are expensive though. I have never broken one yet although I have
> managed to
> round out the posidrive head on a few ( probably needed a bit of vaseline
> going in ? ), so am interested in this Torex socket head that's mentioned.
Sadly the range of SS screws available in Torx drive is quite limited,
compared to zinc plated. I think for outdoor projects, SS is a must - it
makes life so much easier in the long term.
Grunff
Stefek Zaba
> Sadly the range of SS screws available in Torx drive is quite limited,
> compared to zinc plated. I think for outdoor projects, SS is a must - it
> makes life so much easier in the long term.
"Limited" is dead right: do you know of any suppliers at all? I've taken
to using s/s exclusively on outdoor projects too, and it *is* nice being
able to undo the fixings years later. I've used them in some internal
longer-term projects too - like floorboard replacing, where I've seen
normal steel corrode after a few years.
At least for "normal" steel (BZP, bright zinc plated, i.e. "silver" screws),
I feel the different head patterns give you a tradeoff in ease of initial
driving versus eventual removal. Slots have the great advantage that they
can be cleaned out years later with a simple scraping action, but are of
course more prone to the driver slipping out. Yer fancy-pantsy Pozidriv,
Torx, and square heads give you a firmer action on the way in, but if you
need to remove the screw years later once it's accumulated grit, gunge, and
some rust, they're going to be harder to get a good purchase on and will be
more likely to round off. (And a slot-drive is easier to fit an impact driver
into, deepen with a hacksaw blade, and all those other bodging approaches
well-documented, ISTR, in one of the car maintenance group FAQs.
Cheers, Stefek
Simon Avery
Hello ch...@areti.co.uk
> c| Next step down gold metric, (e.g. ScrewFix Goldscrews)
> c| presumably
> c| no advantage except that of being a bit cheaper. I did
> c| find (when
> c| I used these) that they were fairly easy to break.
Similar thing here. Lovely to use, go in easy - but occasionally
break.
> c| Silver colour twin thread screws (e.g. Screwfic
> c| Quicksilver R
> c| Twinthread). I don't know much about these as I
> c| migrated from
> c| old-fashioned steel slotted screws straight to the
> c| metric 'gold'
> c| screws.
After the breakages of Screwfix's Golds, I went for these. I am
impressed - even the incredibly cheap ones. No breakages so far (some
two thousand on), the odd one or two deformed ones (blocked heads),
but generally very good. Much stronger than gold, but slower to use
and as they're wider, may need pre-drilling.
> c| What I'm really after knowing is whether I would notice any
> c| big differences by moving from the TurboGold screws to
> c| either Zinc plated (i.e. silver coloured) ones or to
> c| stainless steel.
I don't use SS at all, so can't comment there, sorry.
> C| I do a fair amount of work out of doors so
> c| stainless does have some attractions but would I lose out in
> c| other ways (strength, ease of driving, etc.) if I used them?
I don't think so - SS should be as strong as normal ZP ones, I'd have
thought.
> c| Are 'silver' screws as corrosion resistant as the gold ones?
Yes, IMO. (Two years on, outside, no sign of rusting)
> c| Do the twin thread silver screws drive more easily or less
> c| easily?
TBH, I haven't noticed much difference.
--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/
Personal pages: http://www.digdilem.org/
ch...@areti.co.uk
in the description. (Assuming you mean the "T-Star Countersunk"
screws)
--
Chris Green (cgr...@x-1.net)
ch...@areti.co.uk
capable of driving 6mm x 100mm screws into undrilled fence posts.
Thus, if I forget to set the torque, it will snap smaller screws quite
happily. What I meant though was that a few of the screws have broken
in service and/or when I have tried to remove them. However far fewer
have broken than of the older GoldScrews.
--
Chris Green (cgr...@x-1.net)
Will Dean
news:0dJM7.20796$k55.4...@monolith.news.easynet.net...
> >
> Ah, they are actually Torx heads are they, it's not completely clear
> in the description. (Assuming you mean the "T-Star Countersunk"
> screws)
It doesn't feel to me that Torx is a very good drive for power-driven
woodscrews, compared with Pozi because it's not self-centring - isn't is a
pain to fit the driver into the screw?
It also seems that you're more likely to break something (driver bit or head
of screw) because there isn't an easy torque release that comes from
reducing the pressure on the driver.
Maybe the woodscrew drive is tapered in some way?
Will
ch...@areti.co.uk
> I have used stainless steel exclusively on my outdoor projects this year.
> They are expensive though. I have never broken one yet although I have
> managed to
> round out the posidrive head on a few ( probably needed a bit of vaseline
> going in ? ), so am interested in this Torex socket head that's mentioned. I
> take the
> view that they won't weep rusty stains all over the wood and they'll be easy
> to remove in future if I need to modify/move stuff. I had to drill out
> plenty of old
> bright steel screws ( totally corroded after 15 years ) from the garden
> gate I was dismantling and didn't enjoy that at all. I don't have any
> comparative
> long-term info on the corrosion resistance of
> zinc-plated/passivated/stainless fasteners though.....
>
that I have used are basically sound and quite easy to remove though
they are discoloured.
--
Chris Green (cgr...@x-1.net)
Paul C. Dickie
Dave Liquorice <new...@howhill.com> writes
>Well they won't rust, ever. (asuming a decent grade of stainless
>steel). All the others you mention will and possibly quite quickly
>depending on the conditions and the quality of the zincification,
>hop dip galvanised is the only real way to protect steel outside.
I dare say that's fun to behold...
--
< Paul >
Paul C. Dickie
ch...@areti.co.uk writes
>I use a fairly powerful 12 volt Skil drill/driver which is quite
>capable of driving 6mm x 100mm screws into undrilled fence posts.
>Thus, if I forget to set the torque, it will snap smaller screws quite
>happily. What I meant though was that a few of the screws have broken
>in service and/or when I have tried to remove them. However far fewer
>have broken than of the older GoldScrews.
Don't you grease them first?
--
< Paul >
Peter Parry
<andrew...@onetel.net.uk> wrote:
>I have used stainless steel exclusively on my outdoor projects this year.
>They are expensive though.
They are also not especially corrosion resistant in wet wood (oak
especially). Stainless steel creates its own galvanic couple and is
quite partial to closed cell corrosion in wet anaerobic conditions
where the protective oxide film is broken down and cannot reform.
This causes waisting and snapping when trying to remove them.
If immersed in water a stainless steel fitting can often survive no
better than mild steel.
--
Peter Parry.
http://www.wpp.ltd.uk/
Simon Avery
Hello Paul
>> I use a fairly powerful 12 volt Skil drill/driver which is
>> quite capable of driving 6mm x 100mm screws into undrilled
>> fence posts. Thus, if I forget to set the torque, it will
>> snap smaller screws quite happily. What I meant though was
>> that a few of the screws have broken in service and/or when
>> I have tried to remove them. However far fewer have broken
>> than of the older GoldScrews.
> PCD| Don't you grease them first?
Goldscrews are pre-lubricated, at least, the screwfix ones are.
The problem is that the shank is thinner than normal screws.
Andy Hall
"Simon Avery" <SPAM.B.GO...@softhome.net> wrote in message
news:10068...@digdilem.org...
> "Paul C. Dickie" <p...@bozzie.demon.co.uk> wrote:
>
> Hello Paul
>
> >> I use a fairly powerful 12 volt Skil drill/driver which is
> >> quite capable of driving 6mm x 100mm screws into undrilled
> >> fence posts. Thus, if I forget to set the torque, it will
> >> snap smaller screws quite happily. What I meant though was
> >> that a few of the screws have broken in service and/or when
> >> I have tried to remove them. However far fewer have broken
> >> than of the older GoldScrews.
>
> > PCD| Don't you grease them first?
>
> Goldscrews are pre-lubricated, at least, the screwfix ones are.
>
> The problem is that the shank is thinner than normal screws.
>
Slightly longer/larger pilot hole?
.andy
ch...@areti.co.uk
of their advantages in my opinion.
Or are you saying that greasing them first will make them easier to
take out at some distant future date?
--
Chris Green (cgr...@x-1.net)
Peter Parry
>No, both GoldScrews and Turbo Gold screws are 'ready lubricated', one
>of their advantages in my opinion.
>
>Or are you saying that greasing them first will make them easier to
>take out at some distant future date?
Makes them a damn sight easier to get in if my experience of dipping
them in grease (Texguard actually - bit like Waxoyl) before using
large ones to build a shed is anything to go by!
Simon Avery
Hello Andy
>> Goldscrews are pre-lubricated, at least, the screwfix ones
>> are. The problem is that the shank is thinner than normal
>> screws.
> AH| Slightly longer/larger pilot hole?
Well, yes - but one of the selling points for the goldscrew is that it
rarely needs pre-drilling. Splitting is reduced 'cos of the shanks
thinness, and also because they're ruddy sharp (try groping in a
boxfull).
They're not too happy with my pet oak beams, but even drilling a pilot
hole in them is less than easy.
Andy Dingley
>It doesn't feel to me that Torx is a very good drive for power-driven
>woodscrews, compared with Pozi because it's not self-centring
Torx was invented specifically for power driving.
It;s easy to align them, if the screws are magazine fed. The big
advantage is that a Pozidrive can drive badly if mis-aligned (usually
chewing the head) but a Torx is either aligned correctly, or
disconnected completely.
ch...@areti.co.uk
> "Will Dean" <{news}@industrial.demon.co.uk> a écrit :
>
>>It doesn't feel to me that Torx is a very good drive for power-driven
>>woodscrews, compared with Pozi because it's not self-centring
>
> Torx was invented specifically for power driving.
>
> It;s easy to align them, if the screws are magazine fed.
Not may of us here (D-I-Y'ers) use magazie fed screws so that's a bit
irrelevant really. The question is whether it's easy to get the bit
into the screw when (for example) you cant see it because it's down a
dark hole.
> The big
> advantage is that a Pozidrive can drive badly if mis-aligned (usually
> chewing the head) but a Torx is either aligned correctly, or
> disconnected completely.
>
Generally good Pozidrive head screws (e.g. TurboGold and similar) are
so hard that the head is damaged very little by the occasional
pop-out.
On balance I think I'm going to stay with Pozi screws for the moment.
--
Chris Green (cgr...@x-1.net)
patndave
<ch...@areti.co.uk> wrote in message
news:sRqN7.659$sd3.5...@monolith.news.easynet.net...
>
> > The big
> > advantage is that a Pozidrive can drive badly if mis-aligned (usually
> > chewing the head) but a Torx is either aligned correctly, or
> > disconnected completely.
And Torx will snap off unless the bit is of the type that is designed to
drive at an angle. Think of those ball ended Allen keys that were designed
for such use.
A normal hexagon section but with a waist around it about one diameter from
the end, and a round end that allows it to be used at a small angle from the
axis of the screw.
Dave
Paul C. Dickie
ofthome.net> writes
>"Paul C. Dickie" <p...@bozzie.demon.co.uk> wrote:
>>> I use a fairly powerful 12 volt Skil drill/driver which is
>>> quite capable of driving 6mm x 100mm screws into undrilled
>>> fence posts. Thus, if I forget to set the torque, it will
>>> snap smaller screws quite happily. What I meant though was
>>> that a few of the screws have broken in service and/or when
>>> I have tried to remove them. However far fewer have broken
>>> than of the older GoldScrews.
>
>> PCD| Don't you grease them first?
>
>Goldscrews are pre-lubricated, at least, the screwfix ones are.
And you rely on that? I always smear them with a little silicone wax
polish before driving them, to make life a little easier for the poor
b*gger (probably me!) who'll have to remove them a year or three from
now...
>The problem is that the shank is thinner than normal screws.
Perhaps that's why they're cheaper?
--
< Paul >
Paul C. Dickie
<pe...@wpp.ltd.uk> writes
>They are also not especially corrosion resistant in wet wood (oak
>especially). Stainless steel creates its own galvanic couple and is
>quite partial to closed cell corrosion in wet anaerobic conditions
>where the protective oxide film is broken down and cannot reform.
>This causes waisting and snapping when trying to remove them.
If that were true for *all* grades of stainless steel, it would be very
bad news for the nuclear industry where, I believe, stainless steel
piping is not exactly unknown in the primary coolant circuit of PWRs.
>If immersed in water a stainless steel fitting can often survive no
>better than mild steel.
Which, of course, explains why stainless steel sinks go rusty...
--
< Paul >
Paul C. Dickie
ch...@areti.co.uk writes
>No, both GoldScrews and Turbo Gold screws are 'ready lubricated', one
>of their advantages in my opinion.
>
>Or are you saying that greasing them first will make them easier to
>take out at some distant future date?
Yes.
It also makes it easier to drive them in the first place.
--
< Paul >
Peter Parry
<p...@bozzie.demon.co.uk> wrote:
>If that were true for *all* grades of stainless steel, it would be very
>bad news for the nuclear industry where, I believe, stainless steel
>piping is not exactly unknown in the primary coolant circuit of PWRs.
Various grades have different corrosion resistance. You are correct
in assuming that the subject is of extraordinary interest to the
nuclear industry where knowledge of the electrochemical potential and
corrosion property of materials is vital.
>>If immersed in water a stainless steel fitting can often survive no
>>better than mild steel.
>
>Which, of course, explains why stainless steel sinks go rusty...
I realised I'd left out the bit about a stainless steel fitting "in
wood" when I re-read this :-). Actually stainless steel sinks do go
rusty - almost immediately. Chromium (at least 10%) is the defining
material in Stainless Steel. The chromium in the stainless steel has
a great affinity for oxygen, and will rapidly form on the surface of
the steel at a molecular level a film of insoluble chromium oxide
which protects the material underneath from further corrosion.
In closed cell (or crevice) corrosion, well known by wood
boatbuilders, the acidic liquor from the wood attacks this oxide
layer and creates patches, some protected and some unprotected. In
the screw hole air is excluded and the available oxygen used so
eventually the film, can't reform. Closed cell corrosion can also
occur on any protected surface and is also the cause of pitting in
stainless steel components on cars where spots of dirt provide the
air exclusion.
The closed cell corrosion resistance of stainless steel is determined
by the closed cell electrochemical potential between the active and
passive areas. This varies between the stainless steel types ranging
from below 0.2V (316 steel) to 0.45V (304 steel (A2)).
Anything above about 0.1V will potentially cause corrosion. As the
unprotected part is at the lower potential (-0.2V) it is this part
which will corrode. This causes the screw shaft to be eroded and
(eventually) the head to snap off. The great danger of this form of
corrosion is that there is no external staining and the exposed
components remain corrosion free so there is no visible evidence it
is taking place.
Within the “300” series of austenitic stainless steels the Screwfix
screws and fittings are the common grade 304 (A2) which contains 18%
Chromium and 10% Nickel. This will corrode if the conditions are
right. They are certainly unsuitable for marine use below the
waterline or any application where they are likely to be immersed for
any time in salt water. A2 is also the grade commonly used for sinks
(which is why all stainless steel sinks carry warnings about not
using bleach in them - very high levels of halide ions, especially
the chloride ion can also breakdown the passive surface film and
cause staining).
Grade 316 (A4) typically comprises 17% Chromium, 11% Nickel and 2 %
Molybdenum and is widely used to store and transport very aggressive
substances.
The three groups of stainless Steel are :-
Martensitic (C1, C3, C4, C5), with 12 to 18% chromium, these are
magnetic, can be hardened by heat treatment and have poor welding
characteristics. Typically used for knives, fasteners, shafts and
springs. Common grades are 410, 420, 440 (C1, C3, C4).
Ferritic (F1), also contains 12 to 18% chromium but has a lower
carbon level (less than 0.2%). Since the carbon is low, these grades
have a different metallurgical structure. They are magnetic and
cannot be hardened by heat treatment. Their weldability is still
poor. Typically used for vehicle exhaust and fuel lines,
architectural trim, cooking utensils and bank vaults. Common grades
are 409 and 430.
Austenitic (A1, A2, A3, A4, A5), when nickel is added and the
chromium level is increased, the structure changes again.
Austenitic steels are not magnetic and cannot be hardened by heat
treatment (but can be hardened by cold working). Of all the
stainless steels this group have the best corrosion resistance. They
can be easily welded and have excellent cleanability and hygiene
characteristics as well as resistance to both high and low
temperature. They are commonly used for kitchen sinks, architectural
applications such as roofs and gutters, doors and windows, tubular
frames, food processing equipment, food preparation areas, chemical
vessels, ovens and heat exchangers.
Common Grades are 304 (the most common), 310 (for high temperature
use, 316 (for better corrosion resistance) and 317 (for best
corrosion resistance).
There are also ferritic-austenitic grades known as Duplex and
Superduplex produced for specialist applications.
A table showing the composition of the stainless steel alloys is at
http://mdmetric.com/tech/ssgradetable.htm
M Junk
"Peter Parry" <pe...@wpp.ltd.uk> wrote in message news:bjeh0u00ff0920983...@4ax.com...
<Big snip of interesting stuff>
> Peter Parry.
> http://www.wpp.ltd.uk/
Very informative Peter, thanks - would make a good FAQ article if you wanted to send to Phil...
Has anyone also mentioned the problem with stainless steel nuts and bolts? Once had to deal with some equipment where the spec was
all contact parts to be 304L stainless (or better), the supplier had also used stainless steel nuts and bolts. Subsequently anytime
bits had to be dismantled the nuts were always seized and had to use brute force to break the bolts. Apparently stainless steel
under stress like this 'grows' together, unless protected with some special grease?
roger
> Chromium (at least 10%) is the defining
>material in Stainless Steel. The chromium in the stainless steel has
>a great affinity for oxygen, and will rapidly form on the surface of
>the steel at a molecular level a film of insoluble chromium oxide
>which protects the material underneath from further corrosion.
>
>In closed cell (or crevice) corrosion, well known by wood
>boatbuilders, the acidic liquor from the wood attacks this oxide
>layer and creates patches, some protected and some unprotected. In
>the screw hole air is excluded and the available oxygen used so
>eventually the film, can't reform. Closed cell corrosion can also
>occur on any protected surface and is also the cause of pitting in
>stainless steel components on cars where spots of dirt provide the
>air exclusion.
>
>The closed cell corrosion resistance of stainless steel is determined
>by the closed cell electrochemical potential between the active and
>passive areas. This varies between the stainless steel types ranging
>from below 0.2V (316 steel) to 0.45V (304 steel (A2)).
>
>Anything above about 0.1V will potentially cause corrosion. As the
>unprotected part is at the lower potential (-0.2V) it is this part
>which will corrode. This causes the screw shaft to be eroded and
>(eventually) the head to snap off. The great danger of this form of
>corrosion is that there is no external staining and the exposed
>components remain corrosion free so there is no visible evidence it
>is taking place.
>
--
roger
del x's to email
Phil Addison
<my....@ntlworld.com> wrote:
>
>"Peter Parry" <pe...@wpp.ltd.uk> wrote in message news:bjeh0u00ff0920983...@4ax.com...
>> On Fri, 30 Nov 2001 15:03:11 +0000, "Paul C. Dickie"
>> <p...@bozzie.demon.co.uk> wrote:
>
><Big snip of interesting stuff>
>
I thought so too, but...
>would make a good FAQ article if you wanted to send to Phil...
... don't you think it's a tad specialised for the FAQ?
--
Phil Addison
UK.D-I-Y FAQ http://www.diyfaq.org.uk/
Lee Shepherd
>They are also not especially corrosion resistant in wet wood (oak
>especially). Stainless steel creates its own galvanic couple and is
>quite partial to closed cell corrosion in wet anaerobic conditions
>where the protective oxide film is broken down and cannot reform.
>This causes waisting and snapping when trying to remove them.
What's that in English?
--
Lee Shepherd, MIOC, LCGI
(Master Carpenter)
S&G Joinery Services
Dave Plowman
Lee Shepherd <L...@sheppy.demon.co.uk> wrote:
> >They are also not especially corrosion resistant in wet wood (oak
> >especially). Stainless steel creates its own galvanic couple and is
> >quite partial to closed cell corrosion in wet anaerobic conditions
> >where the protective oxide film is broken down and cannot reform.
> >This causes waisting and snapping when trying to remove them.
> What's that in English?
They rot through when wet. ;-)
--
* Always borrow money from pessimists - they don't expect it back *
Dave Plowman dave....@argonet.co.uk London SW 12
RIP Acorn
Peter Parry
<L...@sheppy.demon.co.uk> wrote:
>What's that in English?
The screw shank, hidden in the wood, suffers what appears to be
erosion and is gradually eaten away. As explained in the later post
the particular problem with this is that the damage is not visible
from the outside where the screw head remains undamaged and bright.
Simon Avery
Hello roger
>> Chromium (at least 10%) is the defining
>> material in Stainless Steel. The chromium in the stainless
>> steel has a great affinity for oxygen, and will rapidly
>> form on the surface of the steel at a molecular level a
<snip>
> r| Could we have this excellent summary on the FAQ please?
Seconded. Very useful information.
Phil Addison
SPAM.B.GO...@softhome.net (Simon Avery) wrote:
>roger <ro...@zczcxxxx.demon.co.uk> wrote:
>
>>> Chromium (at least 10%) is the defining
>>> material in Stainless Steel. The chromium in the stainless
>>> steel has a great affinity for oxygen, and will rapidly
>>> form on the surface of the steel at a molecular level a
>
><snip>
>
>> r| Could we have this excellent summary on the FAQ please?
>
>Seconded. Very useful information.
I already said...
>I thought so too, but...
>
>>would make a good FAQ article if you wanted to send to Phil...
>
>... don't you think it's a tad specialised for the FAQ?
... so come on, convince me of the relevance to more than a tiny
minority here. If it exists on a website already, and I doubt that PP
wrote it on the fly, I could put in a pointer to it.
Peter Parry
wrote:
>... so come on, convince me of the relevance to more than a tiny
>minority here. If it exists on a website already, and I doubt that PP
>wrote it on the fly, I could put in a pointer to it.
I am deeply hurt to be accused of plagiarism - it was research (ie
copied from many sources not just one) it even included some original
bits :-).
It doesn't exist in that form or even substantially in that form
anywhere else.
Phil Addison
<pe...@wpp.ltd.uk> wrote:
>On Mon, 03 Dec 2001 23:45:12 +0000, phi...@bigfoot.com (Phil Addison)
>wrote:
>
>>... so come on, convince me of the relevance to more than a tiny
>>minority here. If it exists on a website already, and I doubt that PP
>>wrote it on the fly, I could put in a pointer to it.
>
>I am deeply hurt to be accused of plagiarism - it was research (ie
>copied from many sources not just one) it even included some original
>bits :-).
Sorry Peter; In that case you can read the above as a compliment.
>It doesn't exist in that form or even substantially in that form
>anywhere else.
Several have said they would like it in the faq (well, 3 or 4) against
none (if you don't count me!), so if you think it appropriate I'll put
it in. Unless you prefer to put it on your site in which case I can
point to it.
Simon Avery
Hello Phil
>>>> Chromium (at least 10%) is the defining
>>>> material in Stainless Steel. The chromium in the
> PA| ... so come on, convince me of the relevance to more than a
> PA| tiny minority here. If it exists on a website already, and I
> PA| doubt that PP wrote it on the fly, I could put in a pointer
> PA| to it.
Sure, but it interested /ME/, and that's the only reliable guideline
I've got. I use tools, and sometimes I'm curious to know how they're
made...