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
