Discovering Technical Math and the Tools of the Trades
Chapter 2: Discovering Technical Math and the Tools of the Trades Spreadsheet programs are your friends
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Chapter 2: Discovering Technical Math and the Tools of the Trades
Plumbing and pipefitting calculators
Flow calculations are important in many plumbing applications, and a pipe flow calculator is a great example of the computerization of complex formu- las. This calculator helps you work out pipe pressure drop and pipe diam- eters. Visit www.pipeflowcalculations.com/.
Roof surface area calculator
For roof coatings, one estimating calculator uses a table. You start with the interior square footage of the house to be roofed. Then you make allowances for roof overhang, the thickness of the walls, and the slope of the roof. After that, you consider the type of roof to be coated, as well as wastage. When those figures are all in place, the table gives you the total roof surface area to buy coatings for. You can find this tool at www.somay.com/roof_coatings/
roof_calculate/roof_calculate.html.
You can also work out roof surface area from direct measurements or from blueprints, and that may be the smarter way to go because an online roof sur- face calculator can only provide an approximation.
Thermometers and sphygmomanometers
A key part of the certified nursing assistant’s (CNA’s) work is to take a
patient’s vital signs — temperature, blood pressure, and pulse. Thermometers are essential for taking the temperature of the human body. For decades, the temperature was displayed as the height of a thin column of mercury in a glass tube. Now, digital thermometers display temperatures in either degrees Fahrenheit or degrees Celsius.
Blood pressure is measured with a blood pressure cuff, or sphygmomanometer.
That’s easy for you to say! Try saying “sfig-mo” and combine it with “man-om- eter.” That’s the device with an inflatable cuff and gauges. Figure 2-3 shows you an old-fashioned version, but these days, many blood pressure cuffs are digitized, and the CNA can take the readings directly from the instrument. The blood pressure cuff measures systolic and diastolic blood pressure.
Blood pressure measures two kinds of pressures in the arteries, which is why it includes two numbers. A measurement such as 120/80 comes from old blood pressure devices that showed the pressures as the height of columns of mercury in two tubes. So, 120 refers to a column of mercury pushed up to 120 millimeters by the patient’s systolic blood pressure, while the 80 refers to the patient’s diastolic blood pressure. For more on working with metric units, see Chapter 6.
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Chapter 2: Discovering Technical Math and the Tools of the Trades
Figure 2-3:
An old- fashioned sphygmo- manometer.
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The CNA determines your pulse rate by counting just a few heartbeats while watching a watch for a few seconds; she then multiplies to get beats per minute. Pulse is traditionally measured by using a stethoscope and a watch.
However, today’s digital blood pressure cuffs include pulse rate in the dis- played output.
Micrometers, calipers, and gauges
Machinists have incredibly complex jobs, making the parts for just about every item you use. Even parts made of plastic are machined, or the molds to make them are. At its simplest, a machinist does drilling, milling, turning, and grinding. Except that’s not simple.
Nowadays, most machine tools (such as mills, turning centers, and drilling machines) are computerized. The machine does much of the cutting for the machinist, but that doesn’t make things automatic. Every step has to be pro- grammed, and the machinist has to calculate feed rates and cutting speeds, based on the material and the cutting tools used.
Online and downloadable calculators can help machinists with the needed calculations. (Check out the earlier section “Machinist calculators” for infor- mation on these calculators.)
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When the work is complete, the machinist uses micrometers, calipers, and gauges (shown in Figure 2-4) to make sure the work is accurate. These are measurement tools, not math tools.
Micrometers are also common in engineering applications wherever you must measure small dimensions precisely. You see calipers used in a variety of fields, including automotive technology (see the example in Chapter 15) and medicine.
Figure 2-4:
Micro- meters, calipers, and gauges.
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Automotive tools
The local garage says that its mechanics can acquire up to $50,000 in tools after just a few years working. Many are specialty tools, such as the gas analyzer in Figure 2-5, used only in auto work. Devices like brake thickness gauges, coolant testers, and hand code readers require measurement and recording information, not math.
One thing auto technicians won’t want to acquire on their own is a diagnostic computer, which analyzes the various computer systems in a vehicle. Because so many cars are managed by one or more computers, it takes a shop diag- nostic computer (with frequent upgrades) to be able to read the codes that cars generate.
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Chapter 2: Discovering Technical Math and the Tools of the Trades
Figure 2-5:
Many auto- motive tools, such as the gas ana- lyzer, are unique to mechanics.
The smog check computer (formally, an emission analyzer) is another com- puter at the auto mechanic’s shop. It determines whether your car meets your state’s emission standards. After a number of visual checks (for example, fuel cap, crankcase smoke), the mechanic connects an RPM measurement device and puts a probe in the tailpipe. The computer does the rest, including sending the results over phone lines to the Department of Motor Vehicles.
In a world with that much automation, it’s kind of a comfort to know that you still measure cylinder bores (diameters) and brake pads (thickness) with manual tools (calipers and brake thickness gauges, respectively; see the pre- ceding section for more on calipers).
Tire pressure is a common measurement at the garage, with digital gauges often replacing the older mechanical gauges.
One great retro tire measurement that doesn’t even involve math is the penny test for tire tread depth. Place a penny into several tread grooves on the tire, with Lincoln’s head pointing in. If part of his head is covered by the tread, you have more than inch of tread depth remaining. Note: Legal tread depth is defined in 42 states as inch, with some variations in other states.
Carpentry tools
As a carpenter, your work is measurement- and calculation-intensive. That’s no surprise. What is a surprise is that, with all of the computerized measuring tools available, the carpenter’s tape measure is probably the most frequently- used tool of the trade. You use it to make measurements and also to apply
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the results of your calculations to wood that’s to be cut or drilled. The math involved is usually arithmetic (addition, subtraction, multiplication, and divi- sion), which we cover in Chapters 4 and 5.
The steel square may be a contender for second place. That tool helps you lay out right angles, but it’s more important for laying out rafters, hip rafters, and stairs. When you lay out a roof pitch, the math is arithmetic, with a bit of ratio work thrown in. (See Chapter 8 for more on ratios.) A great low-tech carpen- ter’s tool is the spirit level (which you probably know as just the level). It’s a short length of wood or metal with a small liquid-filled tube in the middle. The tube contains a bubble; when the level is horizontal, the bubble rests between two marks. Figure 2-6 shows you an example. High-class spirit levels may have additional tubes for measuring vertical or 45-degree inclinations.
Figure 2-6:
A level.
The level has pretty much resisted going high tech. However, newer laser levels project straight lines with the touch of a button. What makes the line level with this device? Yes, a little built-in bubble spirit level.
Bricklaying tools
Bricklayers need their work to be level and straight. It’s essential and (along with mortar throwing) is part of why bricklaying is an art form. Chalk lines (made with spirit levels such as the one shown in Figure 2-6 and a tool called a chalk line, shown in Figure 2-7) are important. Math is secondary in the basic work; the important thing is to use the tools correctly.
However, as a bricklayer, you need to use a relatively large amount of math in preparing for work. You use multiplication to determine the area of a wall and division to calculate how many bricks the job requires. This figure in turn leads you to calculate how many bags of cement and sand (or pre-mixed mortar) you need for the job. See Chapter 5 for details about multiplication and division.
Figure 2-7:
A chalk line.
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