Conference 7.286::home_work

    Amoung the things I do or have to do around the house I seem to
    always be wanting to calculate something.
    
    When I measure the square footage of a floor or deck I always seem
    to be left with this rt. triangular area. I can never recall,
    or spell for that matter, the Pathagrien Theorum for this calculation.
    Anyone have it handy?
    
    Also, I want to level off a section of my driveway, so I have to
    order the gravel by the ton. So I need the length, width and depth
    of the area to get sq feet, then I need to convert to yards so I
    can then convert to tons. Any one got an equation I can plug into
    to determine this?
    
    Maybe this could be the official common mans calculation reference
    note!

    
    Dave Kinney

    Area of a triangle: 1/2 x Base x Height
    
    Pythagoreum Theorum: Right Triangle with sides A, B, C with C being
    the longest.
    
    		A^2 + B^2 = C^2
    
    Some common right triangle proportions are 3:4:5 and 5:12:13
    
    Cubic Yards of material to fill an area to a certain depth:
    
    Lenth(feet) x Width(feet) x depth(inches)/(12 x 27) = Yards
    
    Multiply this by tons/yard of the material (ie. sand=1ton/yard)
    to get tons of material needed.
    
    Bob
    
    
    
    

    
 .0> Maybe this could be the official common mans calculation reference note!
    
	Care to rephrase that?
    
    --Therese (an uncommon person)
    

     
    Crushed stone or gravel usually comes in around 1.5 tons/yard
 
    ,   
    Commoner
         ---   

    Sorry, no slight intended.
    
    ...Un-common Persons...

    
    Dave with a very red face

    random useful things for various building purposes:
    
    Weight of water  62 lbs/cubic foot     8.3 lbs/gallon
    
    BTUs = Watts * 3.4    (electric heaters)

    Roof pitch (degrees) = ATAN(rise/run)

    Ref. .1

        You want to divide rather than multiple cubic feet by 27.
    A cubic yard is 27 cubic feet or a cubic foot is 1/27 of a
    yard, which ever may you prefer.

    Peter Duke

If you want to just figure square feet, a calculation that's easy to
understand and figure out, apply these constants to derive yards.

inches of material        yards = square feet times

       2"                         0.00617

       4"                         0.01234567  (yes, that's right)

       6"                         0.01852

       etc. with multiples of the 2" figure

    re .6
    
    I've repeated the equation in .1 below.  Normal algebraic conventions
    say to do operations within parenthesis first.  This means you are
    dividing by the product of 12 x 27, not dividing by 12 and then
    multiplying by 27.  I chose not to simply put in 324 as the divisor,
    so that the origin of the number would be clear (12 inches to a
    foot, 27 cubic feet to a cubic yard).
    
    Lenth(feet) x Width(feet) x depth(inches)/(12 x 27) = Yards
                                              ^-------^
    					      Do this first  
                                                           
    Bob
       

    
    Any general formulas or `rule of thumb' to determine how much surface
    area that 1 gallon of paint or stain will cover.  Would there be
    a difference for exterior vs. interior?
    
    Specifically, I need to estimate how many gallons of solid stain
    I'd need for my exterior cedar clapboard siding.
    
    Thanks,
    John

    The amount of coverage varies depending of if are covering new wood
    or repaint/staining.  Most makers mark on the back of the can how
    much the can will cover under both conditions.
    

    
    
    		Anyone have a rule of thumb for how much Sakrete to
    	buy for a particular size sono tube?  A general rule like
    	how many cubic ft per bag would be best.
    

When we stained our bare cedar clapboards, I figured square footage, figured
on the low end number on the stain can (200 - 400 sq ft), and ordered 15
gallons.  We returned 7 of them.  oops.  Maybe I figured cubic feet?

Anyway, buy more than you figure you'll need.  And not necessarily because
they're from the same dye lot or whatever (we were told this dye-lot advice
applies mainly to things you would look at more closely, like wallpaper).
If you're done painting/staining "reasonably" soon after buying, you should be
able to return the rest with little difficulty.

A bag of Sakrete is .75 cubic feet.

Paul

    Why is there a difference? An 80 lb bag of Grossman's concrete is
    exactly 2/3 cubic feet.
    
    Ray

    
    I know this was mentioned somewhere in this file, but I can't
    find it...
    how does one convert watts to amps?  I know the wattage of a 
    device, but what amp breaker should I use?  
    
    thanx
    debbie
    

    
    
    
                      AMPS = WATTS / VOLTS
    
    

    
    re: -.1
    
    thank you!
    
    deb
    

Does anyone know if there is a way to convert grams/liter to parts/million
(ppm)?

I have some water test results which are in units of grams/liter (actually 
it's probably mgrams/liter, I don't have them here). I am looking at some
water filter specs that are stated in ppm for handling capacity. How can I
compare them?

For example, my water's iron level is 4.9 mg/liter (yeah I know. WOW!). The
filter specs talk about being able to handle up to 30 ppm. How do these 
numbers relate?

					Thanks,
						Mark

 <<< Note 3208.18 by MARX::SULLIVAN "We have met the enemy, and they is us!" >>>
                       -< Converting grams/liter to ppm >-

Does anyone know if there is a way to convert grams/liter to parts/million
(ppm)?

1 ppm = 1 mg/l

Ross

Well, this conversion implies that the thing being measured weighs the same
as water.  I would have thought that ppm was a volume comparison, not
weight-volume.  However, I think the 1-1 ratio is eminently applicable here,
as there are 1 million milligrams in one litre of water.

			Steve

    I'll let you do the algebra
    
    to convert          multiply by     to obtain
    ----------------------------------------------
    grams/liter        58.417       grains/gal
    grains/u.s. gal    17.118       parts/million
    grains/u.s. gal    142.86       pounds/million gallons
    
     - John
    

>     <<< Note 3208.20 by QUARK::LIONEL "Free advice is worth every cent" >>>

Reference book: Basic Science Concepts and Applications

"PPM: A measure of the concentration of a solution. One part per solute in every 
million parts of solution. Generally interchangable with milligrams per litre
in water treatment calculations."

ross

The worst part of this conversation? It was started by me. 

	B.S. Chemistry 1977

I should have remembered! Thanks for the memory joggers.

						Mark

    I have a gambrel and to take advantage of two feet of space I would
    like to push out the wall so that I have 3ft knee wall. the span is
    15.5 ft and I was thinkinking of using 2x10's with 1/2 in plywood in
    between. is this enough? sketch follows
    
                   --------------------ceiling
    		  /-------------------
    		 /||
    	   roof	/ ||wall to be removed
    	       /  ||
    	      /   ||
    	     /    ||
    	    /||   ||
    	   / ||new||
          /  ||wall|
    
           Thanks
    	   Paul
    

    Using 2x10s where?

    
    My question, too.
    
    If the "wall to be removed" was constructed with 2x3's, it's not a
    supporting wall and can be removed with impunity. It it was constructed
    with 2x4's or better, it may be bearing the load of the upper roof.
    

    there is no doubt it is a load bearing wall. I want to replace the
    2x4's with 16 ft 2x10 's is this feasable?
    
    
    Paul

    
    So, the "wall to be removed" is 15.5' long, load-bearing, and you want
    to replace it with a doubled-2x10 beam, yes?
    
                  -----------ceiling                -----------
                 /-----------                      /-----------
                /||                               /|x|doubled
           roof/ ||wall                          / |x|2x10 beam
              /  ||                             /
             /   ||                   ==>      /
            /    ||                           /|
           /     ||                          /||
          /      ||                         / ||knee
         /       ||                        /  ||wall
    
           Thanks
    	   Paul
    
    
    o  I doubt that such a beam would meet code to replace a load-bearing wall
       for that length.
    
    o  In any case, it seems like a lot of effort to get 2 more feet of
       semi-usable space (you can't put a dresser, or much else, against
       a 3' high wall).
    
    An alternative might be to remove a 4-6' section of the wall and add a
    dormer; the small actual space increase, plus the added daylight, make
    it feel like a sizeable extension to the room.
    

yup that's what I want to do.  But you forgot the plywood. :-) so would going to 
2x12's be better?  The attic sketch follows if this helps




 			   .   .\  \
		roof	.    .   \  \
                     .    .       \  \
		  .     .	   \  \  1 x 6 
               .     .  	    \  \
            __________________________\__\_______________  .
 	 ______________________________________________
	/|||| 					    ||
roof   / ||||	    <-- 8.5 ft -->		    ||  2x4 wall load bearing
      /  ||||
     /    2x's and plywood


		Boy this drawing is hard without cad. 

	Paul

    
    Re .29:
    
    The ridge beam in my 20' family room in 3-2x12. The builder thought
    2-2x12 would be enough; the inspector thought differently.
    
    In the same room, I have a 6-opening in a load-bearing wall, with a
    2-2x10 beam. If I had wanted a 12' opening (full opening into an
    existing room), the builder would have needed a stronger beam.
    
    I assume you're referring to 1/2" plywood that is commonly used as a
    spacer in a 2-2xN beam, to make it approximately the same width as a
    2x4. The support added by this plywood is insignificant.
    
    All this leads me to believe that you're going to need at least a
    2-2x12 beam, and even that might not meet code. Also, you need a hefty
    post at each end of the beam to transfer the load, right down to the
    foundation; this has to be tricky for a second-floor renovation.
    
    Then there's head room -- with a less-than-8' ceiling (I assume), a
    finished 12" beam will yield considerably less than 7' net.
    
    For those reasons, I would go with something that requires a smaller
    hole in the support wall -- like a 4-6' dormer.
    
    And, as we so often forget to remind people -- the code and the
    building inspector have the final say on this.
    

    
    I'm curious...does anybody in this notesfile (in the USA) use the
    metric system when they are doing any projects (like building a house,
    shed, doghouse, birdhouse, deck etc.). I've been reading up on
    carpentry and trying to get a feel for how to build things out of wood.
    I work with the metric system every day (although on the very small end
    of the scale, microns, angstroms, nanometers etc) and I think that
    working in the metric system instead of the old english system would be
    much simpler because working with decimals is MUCH easier than working
    with fractions. 
    
    The problems I see with trying to work in metric in the US is the fact
    that all the materials and tools and measuring instruments are based on
    the english system. Also there probably isn't much experience to draw
    on because all the carpenters here use the english system. 
    
    Has anybody here tried to build something using the metric system? How
    about anybody who has built things both ways (this would be a good basis for
    comparison). If you did, which did you like better?
    
    Steve B. 

    Steve,
     I think you have answered your own questions. The tools/materials are
    english. Why change?
    
    Marc H.

    
    I'm just curious to find out if anyone has used the metric system to
    build anything and if they found the measurements/calculations easier.
    I'm sure that somebody makes metric tape measures. 
    
    I remember when I was in school and people were saying that we were
    going to be "forced" to begin using the metric system. So I can sort of
    see where the resistance comes from. I bet if someone took a good look
    and said, "hey, the metric system is EASIER" then the metric system
    would have really taken off. 
    
    Making the change is hard because it's sort of like learning a new
    language, you have to keep translating in your head instead of thinking
    in the new language. 
    
    I guess what I'm really after here is the question: Should we go with
    the flow and use the english system? Or is it worth it to change to
    metric? 
    
    Steve B.

    I see no particular advantage in changing.  Just do everything in
    inches instead of feet and inches, and any "drawbacks" to the English 
    system disappear, pretty much.  You still have fractions of inches
    to deal with, but I think that's minor.
    
    If you could buy 120cm x 240 cm plywood instead of 4'x8' plywood, and
    if the building code specified studs on 30cm centers, and if... but
    one can't, and it doesn't.  I think if you tried to use metric the
    aggravation of trying to impose metric on an industry that assumes
    inches would far, FAR exceed any small convenience in unit conversion
    the metric system might give you.
    
    Besides, these days you can buy a calculator that works in feet,
    inches, and fractions, so you don't have to think about the
    conversions anyway.

To add my 2 cents worth here,  you can go out and buy metric
bolts with metric heads and threads.  You can find metric wrenches
almost enywhere you look.  This is probably due more to the influx of
Japanese and German cars (among others) than due to any kind of
government sponsored program to get Americans to use metric (although
I suppose the U.S trade policy might be considered to be that program
in some kind of convoluted sort of way... but that is another can of
worms).  I can't speak for everyone, but after tinkering around with
enough foreign cars and even some domestic cars (and bicycles, toys, etc.)
that use metric sized parts, I think I have a good feeling for wrench sizes.
It takes some getting used to but it certainly isn't anything that is
impossible.  I will admit that changing the entire industry over to
metric is highly improbable in the near future.

One question that I have is whether it is possible to even go out and buy
a set of metric drill bits (for instance)?  I rather doubt if one could
go to a store to buy 12mm copper tubing but I don't know because I haven't
tried.  I know that in Japan, even they are not totally metric.  They
measure television set screen sizes in diagonal inches, you can buy
2X4's at the lumber yard and buy 2X4 homes (a big selling point
by the way!).  Usually this lumber is imported from Canada or the U.S.
so they use it in english units, but domestic lumber is measured in metric.
If they can deal with inches in their predominantly metric society,
there is no reason why us non-metric people can't use metric (at least
occasionally).

I kind of lost track of what my point is, but if all of the code requirements
were in metric or if all you could buy is metric, it wouldn't phase me
in the least.  When I make toys for my kids or measure something, I use
metric measurements quite frequently.  The problem is that most materials
do not come in metric.  (Just for the fun of it, every once in a while I
go to a lumber yard and ask for a 2-meter board or something else in metric.
I usually get a strange response).

So the short answer to .0 is yes, I use metric whenever I have a chance
but also use the english system when I have to go out and buy some materials.
I use metric measurements because it is easier to add and subtract decimals
than fractions (as you mentioned in .0).

Phil
                       

    re: .4 and metric drill bits...
    Sure, you can get them from any number of industrial suppliers.
    As far as walking into your local hardware store and getting
    some though...not likely.  
    
    

I've seen metric-sized PVC roof panels (intended for same applications as
corrugated fiberglass panels); you have to be aware that the spacing is
not "standard".

			Steve

    
    I always measure in metric, and fortunately most of my measuring tools
    came with me from the UK.  It's a major pain when I break something and
    can't get a metric replacement - like for my Rotring drawing board.
    
    Many building components in the UK are still specified in
    Imperial measure, and you have to be familiar with both systems.
    I just find metric to be easier all round.
    
    Colin

    And of course Imperial is not the same as American inch/pound/seconds.
    
    Americans freak about metric because the conversions seem so hard. 
    The point there is that the conversions are hard because of the i/p/s
    system, not the metric.  I've made a few projects using metric
    measurements and it's much, much easier.  On the other hand, as many
    are pointing out, metric is not just measurements, it is also
    standards, and there is no compelling reason to stop making 8-foot
    2-by-4s or 1/4X20 machine screws.  The French will still think we're
    jerks.

    It's interesting to hear of Japan using 2x4 lumber as an argument that
    Japan is using "inches".  Since a 2x4 isn't 2"x4" (except in my house),
    it really means that they are using American/Engish wood standards,
    rather than English/Imperial units of measurement.  Changing the 
    units (e.g. referring to 4cmx9cm lumber) is a lot easier than
    changing the standards.

    
    The guy at the hardware store assured me that all my adjustable
    wrenches were metric...
    
    JP

    I thought the metric equivalent of a "stud" had slightly different
    dimensions, so that when you have a 2x4 it's more like a 4.xx x 9.xx,
    which makes it ungainly to use, so you're forced into using inches
    for your calculations.  (Of course, this is only theory I picked up in
    a carpentry book, having never seen wood sawn from a metric tree :-)

On the other foot, a 2*4 sure ain't that either, and is a different size
depending on the amount of dressing the wood has ... or at least used to!
Now no matter how well or poorly dressed the 2*4 is, it is still some
fraction of that.  That's nearly as much a pain in the butt as the
metric measuring!!!

Stuart

    
> depending on the amount of dressing the wood has ... 
    
    If it's French dressing it'll be metric. But it all depends on how
    many GRAMMES of fat in the dressing.  No matter how much the size
    varies, you can still build a cool ranch with it.
    
    %-)
    
    
    

    
    
    What do you mean a 2x4 aint that???  Shop at Grossmans.
    Why do you think they leave their wood outside!!!!!!
    
    
    JD

    I need help in setting up a saw to do compound miter cuts and seem
    to have forgotten my trig and geometery and lost my ability to
    rotate 3- dimensional objects in my head.

    I am installing 3" wide molding between cabinets and the ceiling.
    The molding is installed at a 45 degree slant.  The three angles on
    the cabinets I need to cut for are:
    1. 45 degree inside angle (for corner cabinet)
    2. 90 degree inside angle
    3. 90 degree outside angle

    The cuts will be made on a radial arm saw.  What I need to figure 
    out is the angle to swing the arm and the angle to tip the blade.

    thanks in advance, doug

    Doug,
    
    The easiest way to do this is to use a long wedge to prop the molding
    up against the radial arm saws fence at a 45 degree angle, then you
    only need to worr about the simple cuts.  
    
    
    
    					| |
                                       /| |
                                     /m/| |
                        Molding -> /m/xx| |
                                 /m/xxxx| |  <- Fence
                               /m/xxxxxx| |
                             /m/xxxxxxxx| |
                                     ^
                               Wedge |

    Doug
    
    I don't quite follow what you're trying to do?
    
    Are you using crown molding? ie/ on a slant?  I just don't see where
    you're getting the 45 degree angle?
    
    On regular corners, for crown type molding, one of the ways to cut it
    is by holding the molding against the fence as if it were against the
    wall.  You have to hold it real tight.  Then cut @45 degrees.  This
    will give  you a 22 1/2 degree cut. (Try this out w/ a few scraps
    before using your good stuff.)  This is how I did it BEFORE getting a
    compound miter saw.... it's been a  while.
    
     fence
       |    _
       |45 /molding
       |  /                w/ saw also at 45 degrees.
       | /
       || 45
       --------------
    
    good luck
    
    -John

    Right.  I am installing molding at a 45 degree slant.
    
    The other mention of 45 degrees comes in when I interface between
    cabinets along the wall and a corner-cabinet.  Instead of one 90 inside
    angle at the corner, there are two 45 degree angles along the face of
    the cabinets.
    
    I'm getting the impression that a fence with a 45 degree wedge may be
    my best answer.
    
    doug
    

Here is a general equation that you can adapt


Blade angle  =  180/(number of sides) * Cos (slant)

Arm angle    =  180/(number of sides) * Sin (slant)

 Your 90 deg angle would be equal to a closed figure with 4 sides
 Your 45 deg angle would be equal to a closed figure with 8 sides

This equation is actually for determing the setting for making a multi-segmented
sloping container (like a bucket).

Your case 2 and 3 are the same, but you must swing the arm the
opposite direction and tip the blade the other way.

Tom

    
    Torch me if I'm out of line, but did you first check the corners with
    a mitre bevel?  Even when fitting baseboard with simple cuts, few
    corners are bang-on 90deg.  If the carpenters square shows that they're
    off, I usually try them with a mitre bevel & then bisect the angle for
    the correct saw setting.    
    
    Regards,
    
    Colin
                    

    The Irish experience echoes that of the U.K in that both countries had
    the Imperial system of measure nad have had to adopt to the European
    system of metric measurement since joining the E.C.
    Going to a hardware store is an amusing experience in that, while the
    customer and the attendant will refer to timber in feet and inches, the
    order form will be completed in meters. One may ask for a 2X3 ,8 ft
    long and the form will show 50mm X 75mm , 2.6m....
    Practically all items are metric but there can be a problem adding on to
    old houses, especially plumbing, where hybrid fittings are required.