Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?

MTIA


--
bof at bof dot me dot uk

bof wrote:

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm
--
Kevin Poole
****Use current date to reply (e.g. )****

In message , Kevin Poole
writes


bof wrote:
Anyone tell me the correct definition for the length of a
countersunk screw that's 5mm long overall, comprising a 3mm threaded
section plus a 2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something else?


5mm

Thanks,

I should have asked originally, is that the same with a pan head too?


--
bof at bof dot me dot uk

On May 27, 4:06 pm, bof wrote:
In message , Kevin Poole
writes



bof wrote:
Anyone tell me the correct definition for the length of a
countersunk screw that's 5mm long overall, comprising a 3mm threaded
section plus a 2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something else?

5mm

Thanks,

I should have asked originally, is that the same with a pan head too?


For all screw head types, the length is measured to where the surface
of the wood/metal is supposed to go. This is usually the widest
diameter of the head. So if you have a round-head screw with 5mm
thread, and a 3mm diameter dome on top, then that's a 5mm screw.
Similarly, consider one of those screws that Wikipedia describes as
oval, and whose real name I can't remember; a 5mm version would be
3mm thread, 2mm countersinking, and 2mm dome on the top.

In message
,
Martin Bonner writes
On May 27, 4:06 pm, bof wrote:
In message , Kevin Poole
writes



bof wrote:
Anyone tell me the correct definition for the length of a
countersunk screw that's 5mm long overall, comprising a 3mm threaded
section plus a 2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something else?

5mm

Thanks,

I should have asked originally, is that the same with a pan head too?


For all screw head types, the length is measured to where the surface
of the wood/metal is supposed to go. This is usually the widest
diameter of the head. So if you have a round-head screw with 5mm
thread, and a 3mm diameter dome on top, then that's a 5mm screw.
Similarly, consider one of those screws that Wikipedia describes as
oval, and whose real name I can't remember; a 5mm version would be
3mm thread, 2mm countersinking, and 2mm dome on the top.

Thanks again, it's what I was expecting, hadn't thought of the 'oval
head' case though.




--
bof at bof dot me dot uk

On May 27, 4:19*pm, Martin Bonner wrote:
On May 27, 4:06 pm, bof wrote:





In message , Kevin Poole
writes

bof wrote:
*Anyone tell me the correct definition for the length of a
countersunk *screw that's 5mm long overall, comprising a 3mm threaded
section plus a *2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something *else?



... and the follow up trivia question: In a 1/2" BSP pipe. What
measurement of the pipe is actually 1/2"?

Robert

"Kevin Poole" wrote in message
...


bof wrote:

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm

Strangely enough I've been measuring a few bolts to put them back in the
right
draw but my M3 M4 & M5 bolts seemed to be measured as the actual length
of the thread of the bolt i.e excluding the head, but then these are what
I'd call bolts in that they need nuts rather than self 'screwing' although
the
catalogue calls them screws.
I've a box of No. 8 2 inch slot round black japanned woodscrews that
also appear to follow this excluding the head measurement.
The head being aboit 1/10th of an inch.

Unless you choose to believe ...... ;-)

http://www.fastfixdirect.co.uk/code/...nformation.asp




--
Kevin Poole
****Use current date to reply (e.g. )****

In article
,
Martin Bonner writes
On May 27, 4:06 pm, bof wrote:
In message , Kevin Poole
writes



bof wrote:
Anyone tell me the correct definition for the length of a
countersunk screw that's 5mm long overall, comprising a 3mm threaded
section plus a 2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something else?

5mm

Thanks,

I should have asked originally, is that the same with a pan head too?


For all screw head types, the length is measured to where the surface
of the wood/metal is supposed to go. This is usually the widest
diameter of the head. So if you have a round-head screw with 5mm
thread, and a 3mm diameter dome on top, then that's a 5mm screw.
Similarly, consider one of those screws that Wikipedia describes as
oval, and whose real name I can't remember; a 5mm version would be
3mm thread, 2mm countersinking, and 2mm dome on the top.

Raised countersunk IIRC
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

On Tue, 27 May 2008 08:32:09 -0700 (PDT), RobertL
wrote:

On May 27, 4:19*pm, Martin Bonner wrote:
On May 27, 4:06 pm, bof wrote:





In message , Kevin Poole
writes

bof wrote:
*Anyone tell me the correct definition for the length of a
countersunk *screw that's 5mm long overall, comprising a 3mm threaded
section plus a *2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something *else?



... and the follow up trivia question: In a 1/2" BSP pipe. What
measurement of the pipe is actually 1/2"?

The diameter of the 'hole down the middle', which is really the
important parameter rather than the outside diameter :-)

--
Frank Erskine

"RobertL" wrote in message
...

... and the follow up trivia question: In a 1/2" BSP pipe. What
measurement of the pipe is actually 1/2"?

BSP sizes relate to the bore of a wrought iron (2.5" and under) or cast iron
(3" and over) pipe that will take the thread on the outside.

Colin Bignell

fred wrote:

Raised countersunk IIRC

Yes, AKA "instrument head". Length measurement is as for a standard CSK
screw, as if the raised part of the head were not there.

--
Andy

"bof" wrote in message
news

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm is an extremely short screw, sure you don't mean 5cm?

whisky-dave wrote:
"Kevin Poole" wrote in message
...


bof wrote:

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm


Strangely enough I've been measuring a few bolts to put them back in the
right
draw but my M3 M4 & M5 bolts seemed to be measured as the actual length
of the thread of the bolt i.e excluding the head, but then these are what
I'd call bolts in that they need nuts rather than self 'screwing' although
the
catalogue calls them screws.

A screw has a head and is threaded along all its length. A bolt has a
head, followed by a plain shank, followed by a treaded part at the
bottom. A bolt is usually used in a sheer situation, as the shank is not
reduced in diam. by the threads.
A screw is measured from the surface that it has been set on/in and a
blot is measured by the length of the plain shank plus the head if it
was a countersink bolt. This is so that the bolt can pass right through
the joint allowing a washer to be fitted, that covers the small amount
of shank that protrudes.

Dave

On 27 May, 16:19, Martin Bonner wrote:
On May 27, 4:06 pm, bof wrote:



In message , Kevin Poole
writes

bof wrote:
*Anyone tell me the correct definition for the length of a
countersunk *screw that's 5mm long overall, comprising a 3mm threaded
section plus a *2mm deep countersunk head? Is it a 5mm or a 3mm screw,
or even something *else?

5mm

Thanks,

I should have asked originally, is that the same with a pan head too?

For all screw head types, the length is measured to where the surface
of the wood/metal is supposed to go. *This is usually the widest
diameter of the head. *So if you have a round-head screw with 5mm
thread, and a 3mm diameter dome on top, then that's a 5mm screw.
Similarly, consider one of those screws that Wikipedia describes as
oval, and whose real name I can't remember; *a 5mm version would be
3mm thread, 2mm countersinking, and 2mm dome on the top.



They are called "raised head screws".

Dave wrote:

A screw has a head

Not nesser-celery, it might be a grub screw...

A bolt is usually used in a sheer situation,

:-) ITYM "shear".

and a blot is measured by the length of the plain shank plus the head
if it was a countersink bolt.

Uh? The length of bolts is measured exactly as for screws, including the
threaded part of the shank. I've never encountered anyone measuring
bolts only by the plain part of the shank.

--
Andy

Andy Wade wrote:

Dave wrote:

A screw has a head


Not nesser-celery, it might be a grub screw...

Agreed :-)

A bolt is usually used in a sheer situation,


:-) ITYM "shear".

:-( see below.

and a blot is measured by the length of the plain shank plus the head
if it was a countersink bolt.

That should have read...
and a bolt is measured by the length of the plain shank plus the head
if it was a countersink bolt.

This is done so that the calculated thickness of a metal joint in shear
has all shank through it. Any protruding shank can have a washer that
allows the nut to tighten down on it, without being thread bound.



Uh? The length of bolts is measured exactly as for screws, including the
threaded part of the shank. I've never encountered anyone measuring
bolts only by the plain part of the shank.

In my history of engineering, a bolt was always specified as having an
un-threaded shank of length quoted. When I was an apprentice fitter, we
measured boils by diam and plain shank. They were Whitworth and the
plain shanks went up in 1/4 inch increments.

Thanks for the corrections Andy, but I had 2 grand daughters making lots
of noise when I wrote that.

Dave

"Scabbydug" wrote in message
...

"bof" wrote in message
news

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm is an extremely short screw,

Agreed but possible. Using your senario,

sure you don't mean 5cm?

then a 2cm countersunk head is VERY big ;-)

HTH

John

In message , Scabbydug
writes

"bof" wrote in message
news

Anyone tell me the correct definition for the length of a countersunk
screw that's 5mm long overall, comprising a 3mm threaded section plus a
2mm deep countersunk head? Is it a 5mm or a 3mm screw, or even something
else?


5mm is an extremely short screw, sure you don't mean 5cm?

Nope definitely 5mm.

--
bof at bof dot me dot uk

"Dave" wrote in message
...
whisky-dave wrote:

draw but my M3 M4 & M5 bolts seemed to be measured as the actual length
of the thread of the bolt i.e excluding the head, but then these are what
I'd call bolts in that they need nuts rather than self 'screwing'
although the
catalogue calls them screws.

A screw has a head and is threaded along all its length. A bolt has a
head, followed by a plain shank, followed by a treaded part at the bottom.
A bolt is usually used in a sheer situation, as the shank is not reduced
in diam. by the threads.

http://uk.rs-online.com/web/search/s...chTerm=290-528

These are the sorts of things I've referred to a screws, I'd assumed that
all 'screws'
would have the 'pointy end' as very pointed, but bolts have a flat end.

Which is why I'd hammer a screw to start it off but not a bolt.
Well unless I was attaching it to some students neck

On Tue, 27 May 2008 18:40:15 +0100, Scabbydug wrote:

5mm is an extremely short screw, sure you don't mean 5cm?

Not if it's a 3mm or less diameter machine screw. 5mm is a normal sort of
length, 50mm would be exceptional.

"PCPaul" wrote in message
m...
On Tue, 27 May 2008 18:40:15 +0100, Scabbydug wrote:

5mm is an extremely short screw, sure you don't mean 5cm?

Not if it's a 3mm or less diameter machine screw. 5mm is a normal sort of
length, 50mm would be exceptional.

Ah, a machine screw, sorry I was thinking in terms of a wood screw.