With applications such as the “Machinist Buddy” (now available for Android devices), machinists no longer need to take copies of tables to their machines or scrawl calculations on a notepad.
The free version of the app has a number of useful tools for anyone working in a machining environment and is designed with seven main areas—milling, turning, threading, business, geometry, utilities and reference. Your current area will be underlined with a thick blue line, as shown in Figure 1.
Keep in mind that unlike the "Machining Mate" (see review), this app will not perform metric calculations. And like many apps, the free version will display advertising—unless you purchase the app for $2.19.
Milling Calculators
Figure 2. Machinist Buddy milling menu.
To return from a calculator to the home screen, select the Machinist Buddy icon found in the upper left-hand corner of the screen. To return to the previous screen, select the home button . Unfortunately, its position is not in the same location within each calculator. All of the calculators—although useful—are only available in imperial units and not in metric. In addition, when working with a tablet, not all calculator screens will rotate their orientation, thereby forcing users to reorient the screen themselves.
The RPM, surface feet per minute, feed per tooth and inches per minute milling feedrate calculators are all accurate and equivalent to their Machinist Mate counterparts.
Figure 3. Metal removal rate calculator.
The RPM calculators for carbide and HSS tools—although accurate—are limited in that they only work for six materials: aluminum, brass/bronze soft, bronze high tensile strength, copper/copper alloys, free-machining stainless steel and titanium alloys. In addition, they may not use your desired cutting speed. These two calculators are also somewhat redundant because the RPM (general) calculator will already calculate all of the required speeds.
Turning Calculators
The turning functions include calculators for RPM, feed per revolution, inches per minute feedrate, metal removal rate, advance per revolution, RPM with carbide tooling and RPM with HSS tools.
Figure 4. Turning RPM calculator.
In addition, the revolutions per minute calculator (see Figure 4)—although accurate—should be reworded for two reasons: On a lathe, the diameter of the workpiece is used to calculate the RPM, and the tool diameter is only used when making a hole on the center of the part's end face.
Tapping Calculators
Figure 5. Tap drill size calculator.
Geometry Calculators
The nine geometry calculators include radius of arc length, area of parallelogram, volume of cube, volume of cylinder, area of trapezoid, area of triangle, surface area of ball, volume of a ball and volume of a cone. All of these accurately calculate the desired feature.
Utilities Calculators/Tables/Reminders
Figure 6. The X/Y coordinates of seven holes on a 3.5-inch bolt hole circle centered at X2.0 Y1.0 with an angle to the first hole of 15 degrees.
The Cartesian bolt hole calculator (see Figure 6) will quickly generate the X/Y hole center coordinates. For example, if coordinates were required for seven holes on a 3.5-inch bolt hole circle with; 1) the bolt hole circle centered at X2.0 Y1.0 and 2) the first hole located 15 degrees above the horizontal axis. Enter the values as shown in Figure 6, press the Calculate button and the locations will be displayed.
Figure 6. The X/Y coordinates of seven holes on a 3.5-inch bolt hole circle centered at X2.0 Y1.0 with an angle to the first hole of 15 degrees.
Reference Tables/Charts
Lastly, this application contains 10 handy reference tables, charts and diagrams, including an end mill diagram, manual mill diagram, manual lathe diagram, drill point diagram, thread spec diagram, tap drill chart and HSS drill speeds chart, as well as insert grade comparison charts and Morse and Jacob’s taper charts. The insert grade comparison will allow you to determine what grade of carbide from one manufacturer is equivalent to another.
Overall, as a free calculator, there are many helpful items, provided you are aware of its limitations.For more information, check out the Machinist Buddy app on Google Play.