On 11/21/2015 9:45 AM, John McCoy wrote:
Leon lcb11211@swbelldotnet wrote in
:

I was never a draftsman but was headed in that direction when in
school. The trouble with paper and pencil is that the drawing, and
especially if not to scale, only gives you an ideal/concept. It does
not necessarily give correct dimensions.

If the dimensions aren't right, then the drawing isn't right.
There's no point in making an incorrect drawing, whatever
tool you use to make it.

Well if the drawing is not to scale, the drawing is not right. You did
say you did not do true scale. Or do you consider true scale to be full
scale?




You can put dimensions on the drawing but if
not to scale you have no way to guarantee if the drawing is doable
with the dimensions you want.

If the dimensions add up correctly, then it's doable.

I may not be making myself clear about the advantages to using a drawing
program vs. pencil and paper drawing. The advantage to a drawing
program is that it shows 3D at any angle and can show whether the
internal parts fit together correctly. That is not often possible with
a hand drawn drawing, especially if you are not visualizing how the
pieces fit together when you draw it.
Additionally I use a program to import my pieces from a computer drawing
into an optimization program. It is a huge time saver and increases
accuracy dramatically.




There's nothing that says a drawing has to be 1/4inch to the
foot, or even have the same scale vertically as horizontally,
for the dimensions to be correct. By the same token, every
woodworking magazine starts every issue with a "corrections"
paragraph for the dimensions that were wrong in the drawings
in the previous issue, despite using some sort of CAD program
to create the drawing.

That is correct and in fact I could not tell you what scale my printed
drawing are when they print but they are precisely to "some" scale. The
scale does not matter as long as everything is to the same scale. But if
you are not drawing to scale the drawing can easily be deceiving and
dimensions put in by you may not show a problem. With a drawing program
the dimensions are automatically calculated between the points you
choose and will immediately tell you if the part is the correct size.
If you don't use a CAD or drawing program this is very hard to appreciate.




When I make a drawing, I do front view, side view, and top
view (and detail views for internal or assembly if I need
it for clarity). I dimension everything, and I make sure
the dimensions add up. And that includes factoring in tenons,
or overlaps on rabbets, or stuff like that. But I simply don't
bother making it to scale.

Again if you are not drawing to some scale you are not getting an
accurate view of what you are drawing. When you draw to scale you can
measure the drawing to get the true accurate dimensions anywhere in the
drawing. If not drawing to scale you have to mentally make up what the
dimensions will be and that is where an error in calculations can be
entered.



I still cut stuff wrong on occasion, but that's the fault of
poor measuring, not the drawing.

No doubt.

John