The Trig Calculations menu selection is the third menu of the Machinist
ToolBox startup page. It includes fifteen choices:

Chord Data

Cusp Height / Step over

Drill Tip Compensation

Sine Plate

True Position

3-Point Arc Center

Right Triangle Solver

Oblique Triangle Solver

Bolt Circle Calculator

Polygon Calculator

4th Axis Positioning

Universal Angle Head

Thread Calculation

Polar Dimensioning

Tap Drill Calculation

Chord Data

From the Known Data box, specify the two
things you know about the chord (like radius and height). Then enter them in
the white boxes that appear below. When you click the Calculate button, you'll
be shown all other values about the chord.

Cusp Height / Step Over

A great tool when
planning surface finish for three dimensional machining, you first click which
value you know - the step over amount or the desired cusp height. Then enter
that value below (along with the cutter radius) and Machinist ToolBox will show
you the unknown value.

Drill Tip Compensation

You enter
the drill diameter and the point angle, and Machinist ToolBox will respond with
the drill lead.

Sine Plate

Enter the length of your sine plate and
the desired angle you want to set and Machinist ToolBox will tell you the
height of the gage blocks you'll need to get the angle.

True Position

This function is helpful to determine
the value of True Position tolerances as well as to determine whether a hole
location is within True Position tolerance. Enter the X and Y difference from
specified hole center and Machinist ToolBox will tell you the True Position
tolerance.

Three Point Arc Center

Enter
three points and Machinist ToolBox will tell you the center of a circle that
passes through all three points.

Right Triangle Solver

Enter any
two knowns about a right triangle and Machinist ToolBox will tell you
everything else about the triangle.

Oblique Triangle Solver

Enter
what you know about an oblique triangle and Machinist ToolBox will tell you
everything else about the triangle.

Bolt Circle Calculator

Enter the bolt circle's center position, the radius of the pattern, the
number of holes, and the starting angle and Machinist ToolBox will tell you the
XY locations of each hole.

Polygon Calculator

You specify the number of sides on the polygon and the stock diameter or
distance across flats, and Machinist ToolBox will display all information
about the polygon (stock diameter, number of sides, length of side, included
angle, and distance across flats.

Fourth Axis Positioning

This
function is helpful when working with CNC machining centers that have a rotary
axis. It allows you to calculate an XYZ position after a specified rotation. It
works for A axes (rotation about the X axis) and B axes (rotation about the Y
axis).

Universal Angle Head

Thread
Calculation

This function
allows you to determine the "over the wires" value for external
thread measurements. Specify the thread form, enter the number of threads per
inch (or pitch), enter the pitch diameter and press the calculate button.
Machinist ToolBox will respond with recommended wire size, the lead angle, and
measurement over the wires.

Polar Dimensioning

This function
allows you to convert vrom polar to XY (rectangular) coordinates and
vise-versa. Enter what you know and press calculate. Machinist ToolBox will
fill in the blanks.

Tap Drill Calculation

Specify
what you know about the thread to be tapped and Machinist ToolBox will tell you
the tap drill size to use.