On 11/30/2010 10:54 AM, Pete Keillor wrote:
On Tue, 30 Nov 2010 10:31:46 -0800, Tim
wrote:

On 11/29/2010 11:07 PM, Andrew VK3BFA wrote:
Bloody metric measurements - great system, couldn't and wouldn't argue
against it. But.....

Consider this scenario, good people. Ducted heating furnace in the
roof was having a good go at coming through the ceiling (being a
skilled metalworker, and a RCM lurker, I knew straightaway something
was wrong..) Turned out to be crappy install job, vis
1.Vent pipe not sealed properly (so it leaked)
2.Was sitting on a sheet of particle board crap stuff so it rotted
through
3.No drip tray set up for stuff ups.

So. Decided to get a drip tray made, its a metric world, so did it all
in Metric so as to give the order for the tray to the local plumbing
supply place. Measured L by B, added 10mm each side for the folded
lip, and put the order in. Picked it up, thought "Mmmm..."

Seems I had stuffed up the decimal point in my metric calculations -
was 200mm wider than required (length was stuffed too, but that was OK
- was room up in the roof cavity) so, couldnt get the ******* up
through the access hatch into the roof. So, had to cut it down - heaps
of work...

The Moral - I cant think in Metric, cant visualise in Metric, cant
look at metric measurements and think "nah, no way - too wide/long/
narrow thick etc etc"

How you guys cope - bloody sick of doing this...

Andrew VK3BFA.

I remember that 10mm is very close to four inches, and go from there.

cm.

I also make the occasional factor of ten error...

When I'm doing engineering calculations I get everything into metric,
and go from there. This probably has a lot to do with the fact that
most times I'm doing electrical power conversion stuff, and Volts, Amps,
Watts, etc., are all native metric quantities (there are native-English
measures of all of these, too, which used to be common -- argh!). So
it's natural to have all my distances, forces, torques, etc., in metric,
too, as most of the conversion factors then become 1. And it's _easy_
to multiply or divide by 1.
--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html