Marcus, I'm a diehard metric nerd. I use SI exclusively in all my classes
and writings, and proselytize it to the point of obnoxiousness. But I have
to tell you that, when I do building, I put away my metric tape and get out
my wombat tape because its easier, MUCH MUCH EASIER, given the fact that
absolutely no metric building materials are available here. Construction
workers are not metric ideologues. They want to get the job done as
efficiently as possible, make some money, and go home.
Let me explain one more time. If you are still not convinced, I can only
suggest you go out and build your own building with all-wombat parts.
I think most people on this list are used to working with small and/or
precise things. But we need to understand that most people deal with big
and/or imprecise things. There is no NEED or DESIRE to build buildings to
millimeter precision. A perfect and smooth building is an UGLY building.
Concrete block, stucco, tile, and exterior woodwork are SUPPOSED to be rough
and imperfect. In fact, people pay extra to to make them rougher!
Concrete blocks and manufactured and laid to a precision of several
millimeters (but not 1 mm). The spacings, like all modular spacings, are
whole inches. While the location of a single block can vary several
millimeters, the AVERAGE spacing must be very precise, because even a small,
CONSISTENT error (such as results from rounding off a soft-metric
conversion), when multiplied by 100 blocks, becomes a big error. Is that
clear?
> -----Original Message-----
> From: Ma Be
> >
> On Thu, 2 Nov 2000 11:10:35 Dennis Brownridge wrote:
> >Greg and Karl are correct--virtually nothing in building is
> measured on the
> >job to millimeter precision... That's a waste of time...
>
> I think that we've finally come to some agreement here, Dennis!
> :-) However, I sort of dispute a little your sentence below.
>
> >Buildings CANNOT be designed, measured, or constructed to millimeter
> >precision. Many of the components (block, brick, dimension
> lumber) are not
> >even manufactured to millimeter precision (although plywood is).
>
> If this is the current state of the industry, fine. But it seems
> possible to "push the limits" when it comes to tolerances, so if
> one *really* insisted on it I think it *could* be done. Now,
> whether that was necessary is a different story... ;-)
>
> The
> >dimensions on wombat architectural drawings are all whole inches...
>
> Perhaps in the US, but certainly not up here! I've seen quite a
> few such drawings with fractions of inches in them.
>
> ...So drawing dimensions to the millimeter are about 25
> >times more precise than needed. It is false precision, because the last
> >digit is incorrect, whereas on an inch-foot drawing all digits are
> >significant...
>
> Very well, then. If this is the case, Dennis, please explain to
> us why you claim the sentence below.
>
> >HOWEVER, when building a soft-metric building with inch-foot
> parts, you DO
> >have to bother with extreme precision... Otherwise, the error
> would accumulate and
> >the parts wouldn't fit.
>
> ??? But why would this happen with building it in metric and
> would not happen in the ifp building itself??? You hinted above
> that these parts (blocks, bricks...) are NOT manufactured to
> better precision than the inch!!! Do you see the inconsistency
> here, my friend?...
>
> If a part does not offer a certain precision whether you're doing
> things in one scale or the other doesn't matter! You would end
> up with tolerance difficulties, sir!!!
>
> ... Therefore, the "trick" to address that is always in
> adjusting other things, like the amount of mortar, for instance.
>
> Therefore, please don't blame the values in metric for the
> "mishap" or try to convince us that we would necessarily need to
> work with "sub-millimeter" precision!
>
> >Your blocks would be noticeably out of whack with each other and
> with other
> >parts of the building. This is why builders are so unhappy about
> >soft-metrication. It's a big headache for them.
> >...
> Granted, there could be challanges. But I dispute they'd be
> insurmountable to the point of abandoning the whole effort
> altogether. As I indicated earlier since it's undeniable that
> even in metric construction one can still "work" with "ifp"
> components why wouldn't this be true in this case (i.e. when the
> system that is rational is metric and one tries to use "rational"
> ifp components - true, let's put aside the (also) undeniable fact
> that this is one of the very advantages of using the SI system,
> and also the wastage aspect which I already acknowledged)???
>
> Therefore, I can only consider that this is a very lame excuse.
> Granted that the comparison is not entirely fair as there are
> much, much fewer ifp components in metric construction than the
> other way around. But then again, if this is the case it would
> mean it would be time to start pushing suppliers to come up with
> more "metrically rational" components, would it not (or in better
> precision than they are now)???
>
> Marcus
>
>
> Angelfire for your free web-based e-mail. http://www.angelfire.com
>
>
