SU7 and tolerances
 

OK, I got use of a computer with XP and have been learning SU7.
Pretty cool. As a kid, I worked just long enough as a carpenter to be
dangerous, but not to read blueprints. Now I'm trying to create some.
As a mechanical CAD designer, I'm used to working in thousandths of an
inch. I'm sure that level of accuracy is not needed for architectural
drawings. Or is it?

Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length. What kinda tolerances are
typical for framing and the like?

nb

SU7 and tolerances
 

On Sat, 06 Jun 2009 20:40:35 -0600, notbob wrote:

OK, I got use of a computer with XP and have been learning SU7. Pretty
cool. As a kid, I worked just long enough as a carpenter to be
dangerous, but not to read blueprints. Now I'm trying to create some.
As a mechanical CAD designer, I'm used to working in thousandths of an
inch. I'm sure that level of accuracy is not needed for architectural
drawings. Or is it?

Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length. What kinda tolerances are
typical for framing and the like?

nb

Draw all the members actual size (not nomimal). Make general dimensions
work out to the inch, and details to the nearest 1/4" or at least 1/8".
It also helps to understand the nominal sizes for materials so you don't
pay premiums for having to buy the next biggest size (e.g., floor joists
12'-2" long require splices, intermediate girders, or buying 14' long
members.)


--
Steve Hall [ digitect dancingpaper com ]

SU7 and tolerances
 

wrote in message
Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length.

I always design in actual dimensions. I always create my buy list in nominal
dimensions. I usually configure my design program to draw in numbers
divisable by 1/16th's to conform to 1/16" tolerances.

SU7 and tolerances
 

wrote in message
...

OK, I got use of a computer with XP and have been learning SU7.
Pretty cool. As a kid, I worked just long enough as a carpenter to be
dangerous, but not to read blueprints. Now I'm trying to create some.
As a mechanical CAD designer, I'm used to working in thousandths of an
inch. I'm sure that level of accuracy is not needed for architectural
drawings. Or is it?

Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length. What kinda tolerances are
typical for framing and the like?

nb


Use actual sizes for the materials and cut lengths to the degree of accuracy
that you want to build. The hardest part is remembering to use
"Architectural Lettering" vs. Mechanical Lettering. I took architectural
drafting after mechanical drafting and had a hard time learning to be sloppy
with my lettering. IMHO architectural drawings were closer to "sketches"
when compared to mechanical drawing. ;~)

SU7 and tolerances
 

wrote:
OK, I got use of a computer with XP and have been learning SU7.
Pretty cool. As a kid, I worked just long enough as a carpenter to be
dangerous, but not to read blueprints. Now I'm trying to create some.
As a mechanical CAD designer, I'm used to working in thousandths of an
inch. I'm sure that level of accuracy is not needed for architectural
drawings. Or is it?

Woodworking machines may be built to 1/1000 of an inch, wood work is
measured in 1/16 or 1/32 of an inch. I measure everything in 1/16th
because I can't see 1/32, so I use 1/16th + or -, which probably gets me
around 1/32. when drawing stuff up to build, 1/16th is all I need.

Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length. What kinda tolerances are
typical for framing and the like?

Wouldn't make any sense to draw something up using wood dimensions that
existed before the lumber was dried and planed to final size? If you
are using 6" lumber for the floor, and need 50 pieces, you will be off
by 25" if you pretend the lumber is 6" wide, and not 5 1/2". Ordering
the lumber you of course use the rough cut dimensions.


--
Jack
Go Penns!
http://jbstein.com

SU7 and tolerances
 

wrote:
OK, I got use of a computer with XP and have been learning SU7.
Pretty cool. As a kid, I worked just long enough as a carpenter to be
dangerous, but not to read blueprints. Now I'm trying to create some.
As a mechanical CAD designer, I'm used to working in thousandths of an
inch. I'm sure that level of accuracy is not needed for architectural
drawings. Or is it?

Main question. When I'm creating detailed drawings of the deck I'm
repairing, do I create them using nominal dimensions (2"x4") or actual
dimensions (1-1/2"x3-1/2") for lumber? Seems like it should be the
later, specially for cutting to length. What kinda tolerances are
typical for framing and the like?

Use actual dimensions, except when ordering materials ... if you do not,
your drawings will be inaccurate.

Normal tolerance in framing and Architectural/construction drawings is
1/8". For woodworking drawing you will usually be OK with 1/16", but you
can go down to 1/64 using Architectural dimensions, and 0.000000" with
Engineering dimensions:

Model Info|Units to set your Unit tolerance preference for the project.

--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

SU7 and tolerances
 

"Leon" writes:


Use actual sizes for the materials and cut lengths to the degree of accuracy
that you want to build. The hardest part is remembering to use
"Architectural Lettering" vs. Mechanical Lettering. I took architectural
drafting after mechanical drafting and had a hard time learning to be sloppy
with my lettering. IMHO architectural drawings were closer to "sketches"
when compared to mechanical drawing. ;~)

I was fortunate in that I had a machinist teacher who was fanatical
about knowing fraction and metric equivelents. As close as I get to
bilingual. ;)

nb