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'[OT] Selecting a drill bit size for 3 mm screws'
2010\08\05@144638 by V G

picon face
Hi all,

I'm going to be using hex standoffs to stack PCBs on top of each
other. These hex standoffs use M3 screws which I have found to use
screws 3 mm in diameter. For drilling holes appropriate for these
screws, I have chosen to use tungsten carbide drill bits. Should I
select a drill bit exactly 3 mm in diameter (such as this one:
http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255af5e2b6#ht_673wt_913)
or should I select something slightly larger? The question is: will
the screw slide through if I use a drill bit exactly 3 mm in diameter

2010\08\05@154524 by Isaac Marino Bavaresco

flavicon
face
Em 5/8/2010 15:46, V G escreveu:
> Hi all,
>
> I'm going to be using hex standoffs to stack PCBs on top of each
> other. These hex standoffs use M3 screws which I have found to use
> screws 3 mm in diameter. For drilling holes appropriate for these
> screws, I have chosen to use tungsten carbide drill bits. Should I
> select a drill bit exactly 3 mm in diameter (such as this one:
> http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255af5e2b6#ht_673wt_913)
> or should I select something slightly larger? The question is: will
> the screw slide through if I use a drill bit exactly 3 mm in diameter?

A 3mm diameter drill should be OK. 3mm is the diameter of the stock that
is used to make the screw.

If you want to tap a hole for the screw, use a 2.5mm drill bit.

Isaac

__________________________________________________
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2010\08\05@160105 by Vic Fraenckel

picon face
Isaac Marino Bavaresco wrote:
>  Em 5/8/2010 15:46, V G escreveu:
>  
>> Hi all,
>>
>> I'm going to be using hex standoffs to stack PCBs on top of each
>> other. These hex standoffs use M3 screws which I have found to use
>> screws 3 mm in diameter. For drilling holes appropriate for these
>> screws, I have chosen to use tungsten carbide drill bits. Should I
>> select a drill bit exactly 3 mm in diameter (such as this one:
>> http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255af5e2b6#ht_673wt_913)
>> or should I select something slightly larger? The question is: will
>> the screw slide through if I use a drill bit exactly 3 mm in diameter?
>>    
>
>  
Try this site:

http://www.csgnetwork.com/screwmetmachtable.html

It is an excellent table of drill sizing for various mm size screws

Vic Fraenckel
KC2GUI
windswaytoo ATSIGN gmail DOT com

2010\08\05@160231 by Spehro Pefhany

picon face
At 02:46 PM 05/08/2010, you wrote:
>Hi all,
>
>I'm going to be using hex standoffs to stack PCBs on top of each
>other. These hex standoffs use M3 screws which I have found to use
>screws 3 mm in diameter. For drilling holes appropriate for these
>screws, I have chosen to use tungsten carbide drill bits. Should I
>select a drill bit exactly 3 mm in diameter (such as this one:
>http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255af5e2b6#ht_673wt_913)
>or should I select something slightly larger? The question is: will
>the screw slide through if I use a drill bit exactly 3 mm in diameter?

You should simply refer to the data sheet err.. table:

http://littlemachineshop.com/Reference/TapDrillSizes.pdf

Chris conveniently includes the closest US sizes.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
spam_OUTspeffTakeThisOuTspaminterlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

2010\08\05@162146 by Mike Harrison

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face
On Thu, 05 Aug 2010 16:44:21 -0300, you wrote:

{Quote hidden}

You need to think not only about the hole size but any tolerances on the position of the holes. A
3mm screw in a 3mm hole allows no room for errors. If you are just stacking PCBs on other PCBs then
the holes should all be accurate, although it won't hurt to up the hole size to maybe 3,2mm - you'll
probably find this will make assembly easier, as with a very close hole size, the screw will be
quite fiddly to get in the hole, as it will need to be exactly straight before it will go in - a
larger hole will make life easier.
Wher you have something like threaded pillars in a case, you want whichever end gets screwed in
first (typically the end in  the case) to be fairly close in size, e.g. 3.2,  to get the posiiton as
accurate as possible, and slightly larger holes in the PCB to cope with any tolerance errors in the
case hole positions.

2010\08\05@162559 by Michael Watterson

face picon face
 On 05/08/2010 21:07, Spehro Pefhany wrote:
> At 02:46 PM 05/08/2010, you wrote:
>> Hi all,
>>
>> I'm going to be using hex standoffs to stack PCBs on top of each
>> other. These hex standoffs use M3 screws which I have found to use
>> screws 3 mm in diameter. For drilling holes appropriate for these
>> screws, I have chosen to use tungsten carbide drill bits. Should I
>> select a drill bit exactly 3 mm in diameter (such as this one:
>> http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255af5e2b6#ht_673wt_913)
>> or should I select something slightly larger? The question is: will
>> the screw slide through if I use a drill bit exactly 3 mm in diameter?
> You should simply refer to the data sheet err.. table:
>
> http://littlemachineshop.com/Reference/TapDrillSizes.pdf
>
> Chris conveniently includes the closest US sizes.
3.0mm drill hole might damage the thread slightly. Or be very tight. How do you accurately place the hole?
3.2mm if it's precision and you are good.
3.5mm hole for reasonable precision and clearance
If you are rubbish at metal work and there are 4 holes to match an existing thing, consider washers and 4mm :)
2.5mm will work for thin sheet and trilobal self tapping screws.

2010\08\06@044919 by alan.b.pearce

face picon face
> I'm going to be using hex standoffs to stack PCBs on top of each
> other. These hex standoffs use M3 screws which I have found to use
> screws 3 mm in diameter.
Up, that is why they are called M3 ... ;))

But M3 also means a certain thread pitch, see web pages like
http://www.metrication.com/engineering/fastener.htm for the details.

> For drilling holes appropriate for these
> screws, I have chosen to use tungsten carbide drill bits. Should I
> select a drill bit exactly 3 mm in diameter (such as this one:
> http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-
>
/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255a
f5e2b6#ht_67
> 3wt_913)
> or should I select something slightly larger? The question is: will
> the screw slide through if I use a drill bit exactly 3 mm in diameter?

Our norm for drilling for an M3 is a 3.2mm hole. This allows sufficient
play to deal with pole positioning tolerance in both the PCB and what it
is being mounted on, for things to 'just screw together'.

Also I will assume you are aware that you can get the spacers with a
threaded stud on one or both ends (seem to be known as male-female or
male-male as appropriate). E.G.
onecall.farnell.com/ettinger/05-17-344/spacer-unc4-40x5-m3/dp/146
6788
These are very useful when doing a PCB stack.
-- Scanned by iCritical.

2010\08\06@072437 by Michael Rigby-Jones

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face


> -----Original Message-----
> From: .....piclist-bouncesKILLspamspam@spam@mit.edu [piclist-bouncesspamKILLspammit.edu] On
Behalf
{Quote hidden}

/160439853750?cmd=ViewItem&pt=UK_Home_Garden_PowerTools_SM&hash=item255a
f5
> e2b6#ht_673wt_913)
> or should I select something slightly larger? The question is: will
> the screw slide through if I use a drill bit exactly 3 mm in diameter?

You need what is called a "clearance" hole, which for M3 is 3.2mm.  
In practice a 3mm hole will likely work since a 3mm drill bit guided by
hand will most always cut slightly larger than 3mm, but you need to
consider the tolerance stack up of the holes in all the parts you are
screwing together.

Mike

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2010\08\06@075820 by Isaac Marino Bavaresco

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face
Em 6/8/2010 08:24, Michael Rigby-Jones escreveu:
> You need what is called a "clearance" hole, which for M3 is 3.2mm.  
>
> In practice a 3mm hole will likely work since a 3mm drill bit guided by
> hand will most always cut slightly larger than 3mm, but you need to
> consider the tolerance stack up of the holes in all the parts you are
> screwing together.

Unless you clamp all the parts together and drill them all at once.

A bench drill helps a lot, to keep all the hole's axis perfectly parallel.
The thinner the parts you are drilling, the more you can drill clamped
together.

Isaac

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2010\08\06@093640 by RussellMc

face picon face
> > or should I select something slightly larger? The question is: will
> > the screw slide through if I use a drill bit exactly 3 mm in diameter?

> You need what is called a "clearance" hole, which for M3 is 3.2mm.

> In practice a 3mm hole will likely work since a 3mm drill bit guided by
> hand will most always cut slightly larger than 3mm, but you need to
> consider the tolerance stack up of the holes in all the parts you are
> screwing together.

The following is a "very naughty" thing to do and of course real
people [tm] would never do such things.
Can be useful when you don't have the right drill though.

As Michael notes, a hand held drill bit will make a somewhat larger
hole than its nominal diameter.
If you drill the hole and then tilt the drill in the hole at an angle
it will drill a slightly oval hole.
Doing this again at 90 degrees to the first tilt, or at several angles
or rotating work and drill bit conically will produce a more evenly
enlarged hole.

A 4 degree tilt (hard to avoid by hand) will produce a "crater" which
is 3.2mm diameter in 3mm thick material. The centre will nominally
still be almost only 3mm (oval projection of drill is slightly larger)
but in practice it works if "enough" angle is used. Real machinists
and people with a full set of drills are now rising up in fury :-)..

The hole so formed has a conical "crater" and is all in all a nasty
piece of work. BUT it will turn a close interference hole into a
clearance hole with the same drill, and this may sometimes be worth
the nastiness - depending on how "proper" and how desperate you are.

The above only works 'well' in relatively thin material. Say material
thickness is ideally not more than about the same thickness as the
drill diameter and the thinner the better. The truly desperate can
make it work for much thicker material. Somewhere along the line you
are using the drill as a low grade mill and it's something that should
be avopided.
..
Final thought - doing the above sort of thing may tempt people to
hand hold  work and use  a drill press. This is a technical no-no as,
apart from the lack of precision, it encourages the jamming and
throwing of the work. Bad injuries can occur. Death if you are clever
enough, but you'd have to try very hard to do that with a 3mm drill
and a PCB drilling machine. Better, invest in a few appropriate
drills.



2010\08\06@095200 by alan.b.pearce

face picon face
> A 4 degree tilt (hard to avoid by hand) will produce a "crater" which
> is 3.2mm diameter in 3mm thick material. The centre will nominally
> still be almost only 3mm (oval projection of drill is slightly larger)
> but in practice it works if "enough" angle is used. Real machinists
> and people with a full set of drills are now rising up in fury :-)..

Somehow I think solarwind will be better off using a 1/8" drill, which
is quite possibly more easily obtainable in a nearby hardware store than
a 3mm or 3.2mm.
-- Scanned by iCritical.

2010\08\06@100132 by Michael Watterson

face picon face
 On 06/08/2010 14:36, RussellMc wrote:
>>> or should I select something slightly larger? The question is: will
>>> the screw slide through if I use a drill bit exactly 3 mm in diameter?
>> You need what is called a "clearance" hole, which for M3 is 3.2mm.
>> In practice a 3mm hole will likely work since a 3mm drill bit guided by
>> hand will most always cut slightly larger than 3mm, but you need to
>> consider the tolerance stack up of the holes in all the parts you are
>> screwing together.
> The following is a "very naughty" thing to do and of course real
> people [tm] would never do such things.
> Can be useful when you don't have the right drill though.
Standard "cheap" box of bits has 2.5, 3, 3.5, 4mm etc.
As do most non-specialist shops.
That's why I recommend 3.5mm for M3 unless you are expert and have professional gear in which case you would not ask what size to use.

2010\08\06@100241 by RussellMc

face picon face
> Somehow I think solarwind will be better off using a 1/8" drill, which
> is quite possibly more easily obtainable in a nearby hardware store than
> a 3mm or 3.2mm.

I'm glad I thought of that :-).
What a good idea.
3.175 mm (exactly if true 1/8")

2010\08\06@101215 by Spehro Pefhany

picon face
At 09:36 AM 06/08/2010, you wrote:
{Quote hidden}

Anything of reasonable size can be hand-held with a 3mm/0.125" drill
bit. You have enough leverage to easily break the drill, and I can
state this from personal experience. ;-)

Also, twist drills ALWAYS tend to make holes a few thou larger than
their nominal size (maybe 0.1-0.15mm larger). If you want an accurate
hole size, you drill perhaps 0.01" undersize (maybe using a center
drill or spot drill to locate the hole) and then use a reamer.

For a typical clearance hole for M3 and small production, none of this
is very important, just get the hole location reasonably close and use
an appropriate hole size for standard fit (not too tight or too loose)

For real production work these days you'd likely want to specify the hole
size and location using Geometric Dimensioning and Tolerancing (GD&T)
so that each instance of every part ALWAYS will fit together with its
mate.

For example: http://home.eol.ca/~hgibson/tolerances/node6.html

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam.....interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

2010\08\06@111945 by Michael Watterson

face picon face
 On 06/08/2010 15:02, RussellMc wrote:
>> Somehow I think solarwind will be better off using a 1/8" drill, which
>> is quite possibly more easily obtainable in a nearby hardware store than
>> a 3mm or 3.2mm.
> I'm glad I thought of that :-).
> What a good idea.
> 3.175 mm (exactly if true 1/8")
>
>         R
I guess USA  not Metric yet?

You'd get only metric bits in "ordinary" shops in Ireland now. Though Plumbing fittings are still Imperial in our Kmph signed country yet Metric in Mph UK since 1970s.

So yes 1/8th or 3.5mm  (3.2mm is a fancy "professional" size :) )

2010\08\06@120533 by Bob Blick

face
flavicon
face

On Fri, 06 Aug 2010 16:18:32 +0100, "Michael Watterson" said:

> > 3.175 mm (exactly if true 1/8")
> >
> >         R
> I guess USA  not Metric yet?
>
> You'd get only metric bits in "ordinary" shops in Ireland now.
Interested to see what they do in Canada, which is mostly metric from
what I noticed, but I was never in hardware stores.

Cheers,

Bob

-- http://www.fastmail.fm - Does exactly what it says on the tin

2010\08\06@133525 by V G

picon face
On Fri, Aug 6, 2010 at 12:05 PM, Bob Blick <EraseMEbobblickspam_OUTspamTakeThisOuTftml.net> wrote:
> Interested to see what they do in Canada, which is mostly metric from
> what I noticed, but I was never in hardware stores.

I need to order them online. I can't find tungsten carbide bits
anywhere locally

2010\08\06@140232 by Spehro Pefhany

picon face
At 01:35 PM 06/08/2010, you wrote:
>On Fri, Aug 6, 2010 at 12:05 PM, Bob Blick <bobblickspamspam_OUTftml.net> wrote:
> > Interested to see what they do in Canada, which is mostly metric from
> > what I noticed, but I was never in hardware stores.
>
>I need to order them online. I can't find tungsten carbide bits
>anywhere locally.

KBC is not a bad place for such things, though their Canadian
prices are way higher than US Prices, they do have a location in
BC. (3 locations in Canada and 6 in the US).

http://www.kbctools.com

A 1/8" US-made solid carbide PCB drill (1.5" long) is
$3.45 USD = 3.53 CAD or $4.83 CAD.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
@spam@speffKILLspamspaminterlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

2010\08\06@172328 by Herbert Graf

picon face
On Fri, 2010-08-06 at 09:05 -0700, Bob Blick wrote:
> On Fri, 06 Aug 2010 16:18:32 +0100, "Michael Watterson" said:
>
> > > 3.175 mm (exactly if true 1/8")
> > >
> > >         R
> > I guess USA  not Metric yet?
> >
> > You'd get only metric bits in "ordinary" shops in Ireland now.
>
> Interested to see what they do in Canada, which is mostly metric from
> what I noticed, but I was never in hardware stores.

Canada is officially metric, but in many areas it's still a hodgepodge.
Most "construction" stuff is imperial, so pretty much all of our
construction materials are imperial in measurement (4x8, 2x6).

Tools are mostly imperial, although wrenches and sockets often come in
both (mostly driven by cars which have ALOT of metric bolts, my 1988
Olds used a ton of 10mm bolts).
Drill bits are mostly imperial (although more specialty shops will have
metric bits).

About the only major difference you'd see in a Canadian Home Depot vs.
an American is metric sizes for wrenches/sockets, and Robertson
screwdrivers and screws.

TTYL

2010\08\06@211935 by RussellMc

face picon face
> I need to order them online. I can't find tungsten carbide bits
> anywhere locally.

For many purposes 'high speed steel' drills are liable to be good
enough and are much more forgiving.
Tungsten carbide bits are hard but fragile. Put too much side force on
them and they vanish instantaneously (or, that's what your eye doesn't
see happen). For small drills "too much" is not very much at all. You
don't want to handhold a drill when using small TC bits. For drilling
occasional 3mm holes in PCBs a good steel bit will last a long time.



      Russel

2010\08\06@214603 by ivp

face picon face
> For many purposes 'high speed steel' drills are liable to be good
> enough and are much more forgiving

HSS have just about no life at all with FR4, particularly the smaller
diameters, 0.5 - 1mm used for component holes. They blunt after
a few dozen holes. I'd not recommend them for anything but very
occassional use. If you've many 3mm holes to do then cobalt or
tungsten carbide are much more economical in the long run

> You don't want to handhold a drill when using small TC bits

I find the complete opposite to be true, but maybe it's the bad
experiences I've had with poor drill presses. I can't recall ever
breaking a bit when hand-drilling. You do get a better feel for
what the bit is doing

Joe

*
*
**********
Quality PIC programmers
http://www.embedinc.com/products/index.ht

2010\08\06@225135 by Oli Glaser

flavicon
face


--------------------------------------------------
From: "ivp" <KILLspamjoecolquittKILLspamspamclear.net.nz>
Sent: Saturday, August 07, 2010 2:45 AM
To: "Microcontroller discussion list - Public." <RemoveMEpiclistTakeThisOuTspammit.edu>
Subject: Re: [OT] Selecting a drill bit size for 3 mm screws

>> For many purposes 'high speed steel' drills are liable to be good
>> enough and are much more forgiving
>
> HSS have just about no life at all with FR4, particularly the smaller
> diameters, 0.5 - 1mm used for component holes. They blunt after
> a few dozen holes. I'd not recommend them for anything but very
> occassional use. If you've many 3mm holes to do then cobalt or
> tungsten carbide are much more economical in the long run
> http://mailman.mit.edu/mailman/listinfo/piclist

I second that, the smaller HSS ones die very quickly indeed. I have had to change 1 mm bits after ~30 holes. However a 3mm bit may last a bit longer - I hardly ever use one for PCBs as I always order the final boards, with 3.2mm holes for M3.
If it's just a few holes (<100?) though I'd maybe just get a HSS bit, as the larger ones do last a bit longer - but if you need it for quite a lot of drilling go tungsten carbide.

2010\08\07@003400 by ivp

face picon face
> If it's just a few holes (<100?) though I'd maybe just get a HSS bit,
> as the larger ones do last a bit longer

And it's fairly easy to sharpen the bigger HSS sizes. Very thin ones
are fiddly, but large compared with the abraders like wheels and
discs most people would have handy. A whetstone isn't too bad
thoug

2010\08\08@172250 by Dwayne Reid

flavicon
face
At 10:05 AM 8/6/2010, Bob Blick wrote:

>Interested to see what they do in Canada, which is mostly metric from
>what I noticed, but I was never in hardware stores.

Canada may be 'officially' metric - but most of the drill bits that you find in hardware stores are in inch sizes.  Its actually quite difficult to find any metric-size drill bits.

Actual metric-sized hardware, though, is now becoming more readily available from places like Home Depot.  Its used to be that you could find only English / North American sized hardware (4-40, 6-32, 8-32, 10-24, 10-32, etc) but now I see both types of hardware in the bins.

We are in Canada and, at this point, use only North American-sized hardware in our products unless the customer specifically requires metric.

dwayne

-- Dwayne Reid   <spamBeGonedwaynerspamBeGonespamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2010\08\08@175913 by William \Chops\ Westfield

face picon face

On Aug 8, 2010, at 2:22 PM, Dwayne Reid wrote:

> Canada may be 'officially' metric - but most of the drill bits that
> you find in hardware stores are in inch sizes.  Its actually quite
> difficult to find any metric-size drill bits.

It should all be fine.  For a 3mm screw, you should use a number 30  drill (.1285 inch), which is pleasantly neither metric nor imperial  :-)

BillW

2010\08\08@184345 by Michael Watterson

face picon face
 On 08/08/2010 22:22, Dwayne Reid wrote:
> At 10:05 AM 8/6/2010, Bob Blick wrote:
>
>> Interested to see what they do in Canada, which is mostly metric from
>> what I noticed, but I was never in hardware stores.
> Canada may be 'officially' metric - but most of the drill bits that
> you find in hardware stores are in inch sizes.  Its actually quite
> difficult to find any metric-size drill bits.
>
Only three nations have not officially adopted the International System of Units as their primary or sole system of measurement: Burma, Liberia, and the United States.

-- According to Wikipedia, ironically claiming the source is the 2006  US /CIA World Factbook/

It dates from 1791 and the US has been teaching it in schools since the 1960s?

I learnt both Metric and Imperial systems at School in the UK, so I guess I'm almost bilingual. I find it amazing though when I discover electronics companies using Imperial.

It could be worse, we could be using the centimetre for capacitance instead of the Farad ! One cm of capacitance is about 1.113pF I think

"The CGS system has been largely supplanted by the MKS system, based on metre, kilogram, and second. MKS was in turn extended and replaced by the International System of Units (SI)."

1 statvolt = 299.792458 volts.

So metric (using SI) isn't as bad as it could be.

I don't miss Chains, Roods, Grains, Stones, Pounds, Ounces, Furlongs, Yards, Feet, Inches, Miles, Bushels, Farthingdales, tons, Perches.

I like my mm, cm, m Km
my grammes, kilograms
my pico, nano, micro, milli and full Farads.

2010\08\08@225515 by Marcel Duchamp

picon face
On 8/8/2010 3:43 PM, Michael Watterson wrote:
>
> -- According to Wikipedia, ironically claiming the source is the 2006
> US /CIA World Factbook/
>
> It dates from 1791 and the US has been teaching it in schools since the
> 1960s?

As some sage on this list pointed out 10 or more years ago, the US is inching towards metric but has miles to go

2010\08\09@002933 by William \Chops\ Westfield

face picon face

On Aug 8, 2010, at 3:43 PM, Michael Watterson wrote:

> [metric] dates from 1791 and the US has been teaching it in schools  
> since the 1960s?

The schools are teaching it a lot less than they used to.  When I was  in school in the 60s and 70s they taught metric because (and as if) it  was assumed we would convert "real soon now."  Not any more; you tend  to use metric in the sciences, but no wholesale conversion effort.

Of course, my kids also didn't learn about converting quarts to pecks  and bushels...

Electronics is an interesting combination. 0.1 inch pitch is common,  but so is .6mm and .5mm...

BillW

2010\08\09@054451 by RussellMc

face picon face
      BCC: linguaphiles

> As some sage on this list pointed out 10 or more years ago, the US is
> inching towards metric but has miles to go.

That's a rather good pun, as puns go.

Almost usable as part of a graded filter for English language skills.

Sits pondering putting best foot forward, proceeding with a measured
metre, pounding along, slugging it out, if they put even an ounce of
effort into it, ... . Nah.


         Russel

2010\08\09@062620 by RussellMc

face picon face
> I don't miss Chains, Roods, Grains, Stones, Pounds, Ounces, Furlongs,
> Yards, Feet, Inches, Miles, Bushels, Farthingdales, tons, Perches.

Slugs!
You forgot slugs.
Where would we be without slugs ? !!!
We'd be mixing mass and force as the great unwashed now do in most
places on earth aka eg thinking they are using kgf when really using
kgm.
Not realising that their kgms are really a g of Newtons. And worse.

The lbf saved the Brits, and their Colonial inheritors from such a
gross misuse of units.

Deciislug  - about 1.5 kgm
Centislug - about 150 gramm
milli slug = mslug = about 15 gramm
As opposed to an 'Olin' aka 1 Mslug =  about 15 megatonne*
(Names based on small nukes were considered and rejected).

It's enough to make you want a Newton of beer.

Note to readers who have got this far: Apart from the unit name above
that may sound familiar, all the above material is factual E&OE.



Russell

* megatonne has been used in place of the more consistent megatonnem
for technical reasons.
.

2010\08\09@072401 by Olin Lathrop

face picon face
Michael Watterson wrote:
> Only three nations have not officially adopted the International
> System of Units as their primary or sole system of measurement:
> Burma, Liberia, and the United States.

That statement is rather misleading.  The metric system has been legal here
in the US since 1866.  If you meant to say that you are not forced to use
the metric system in the US for private commerce, then that is correct.
Note that the military and other parts of the government require use of the
metric system in some cases.  For example, soldiers are required to
communicate distances in kilometers, "klicks" in their jargon.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2010\08\09@075339 by RussellMc

face picon face
> Note that the military and other parts of the government require use of the
> metric system in some cases.  For example, soldiers are required to
> communicate distances in kilometers, "klicks" in their jargon.

And it used to be mandatory to design mission critical operational
aspects of interplanetary spacecraft in imperial units and then to
convert some of the results to metric before use, I hear. I suspect
that practice may have been stopped one way or the other. (Some say
there was never any truth in the allegations).


  R

2010\08\09@083336 by alan.b.pearce

face picon face
> > Only three nations have not officially adopted the International
> > System of Units as their primary or sole system of measurement:
> > Burma, Liberia, and the United States.
>
> That statement is rather misleading.  The metric system has been legal
here
> in the US since 1866.  If you meant to say that you are not forced to
use
> the metric system in the US for private commerce, then that is
correct.
> Note that the military and other parts of the government require use
of the
> metric system in some cases.  For example, soldiers are required to
> communicate distances in kilometers, "klicks" in their jargon.

Another prime example is NASA, where a certain mission to Mars is known
to have had a problem as one contractor did not use the 'standard'
units.
-- Scanned by iCritical.

2010\08\09@112802 by Dwayne Reid

flavicon
face
At 03:59 PM 8/8/2010, William \"Chops\" Westfield wrote:

>On Aug 8, 2010, at 2:22 PM, Dwayne Reid wrote:
>
> > Canada may be 'officially' metric - but most of the drill bits that
> > you find in hardware stores are in inch sizes.  Its actually quite
> > difficult to find any metric-size drill bits.
>
>It should all be fine.  For a 3mm screw, you should use a number 30
>drill (.1285 inch), which is pleasantly neither metric nor imperial  :-)

Actually, #30 drill bits are quite common - that's the recommended size when using 1/8" pop rivets.  I'm in the middle of an industrial area and I see those particular bits used all the time.

dwayne

-- Dwayne Reid   <TakeThisOuTdwaynerEraseMEspamspam_OUTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2010\08\11@090205 by RussellMc

face picon face
> I don't miss Chains, Roods, Grains, Stones, Pounds, Ounces, Furlongs,
> Yards, Feet, Inches, Miles, Bushels, Farthingdales, tons, Perches.
>
> I like my mm, cm, m Km
> my grammes, kilograms
> my pico, nano, micro, milli and full Farads.

My friend Ken says -

You forgot lots of others  - including (but not limited to):

Furlong (still in everyday use in the racing industry)
Ell (one and a quarter yards)
Dram (or Drachm if you prefer)
Stone
Sack
Scruple
Carat (stil in everyday use)

Knot (still in everyday use in marine and aviation)
Fathom (still in everyday use)

Pint
Gallons (of course)
Bags and Buckets (24 and 4 gallons respectively)
Barrel (42 US Gallons  - still in everyday use in the oil and petrochemical
industries).
Firkin (9 Fallons  - still in use in the brewing industry)
Minim (1/60th of a fluid ounce)

League
Link
Cable
Rod (length  - not to be confused with Rood which is area)
Rope (20 ft  - still in use in marine and lifting/rigging)
Span (9 inches  - still used by brickies)

BTU
Puoundal
Horsepower
PSI

I guess my point is that in in those "superior" countries where metrication is
regarded as being pretty much complete, many (but not all) of the old units are
still in everyday use in one industry or another.

Farthingdale is a good one and actually has two different measures.  The most
common is 1/4 acre which is the same as a rood which is 40 perches  - and which
is within 0.1% of 0.1 hectare (hence 5 acres is very close to 2 hectares).

Compound units can be fun too:

Litres per hundred km is dimensionally equivalent to an area for instance  - my
car does xxx acres (substitute favourite unit of area).  Try to think hard about
what that means.

Then we have the various abominations like metric inches (25.0mm)  - loved in
plumbing.

Measurements of angles and time have never been metricated to any significant
extent (though some have tried).


Regards,

Ken Mardl

2010\08\26@191222 by Gerhard Fiedler

picon face
Olin Lathrop wrote:

> Michael Watterson wrote:
>> Only three nations have not officially adopted the International
>> System of Units as their primary or sole system of measurement:
>> Burma, Liberia, and the United States.
>
> That statement is rather misleading.  
So are you saying that it is the primary system of measurement in the
USA? We know it's not the sole system of measurement, and that statement
doesn't seem to leave much room for misunderstanding.

> The metric system has been legal here in the US since 1866.  If you
> meant to say that you are not forced to use the metric system in the
> US...

Maybe this is a cultural or a language issue, but I read "primary or
sole system of measurement" as "primary or sole system of measurement"
and not as "legal to use" or "forced to use".
> For example, soldiers are required to communicate distances in
> kilometers, "klicks" in their jargon.

And they use 24 hour time, too. They probably spend too much of their
time overseas and are already infected :)

Gerhar

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