CNC Threading
What is the term for the larger of the two extreme diameters in a thread?
minor diameter
root
major diameter
pitch diameter
major diameter
Which G code specifies the threading motion command that works much like G01?
G76
G32
G92
G99
G32
Which 2 types of offsets do you use to assign program zero?
wear offsets and tool nose radius compensation
tool nose radius compensation and geometry offsets
workshift and wear offsets
geometry offsets and workshift
geometry offsets and workshift
Name the 2 ways to retract the threading tool at the end of each threading pass. Which is the more popular of the 2?
- straight retract
- angular retract
- straight retract is more popular
Which Unified thread form class of fit is commonly used in the aerospace industry?
class 3
What is the term for the smaller of the two extreme diameters in a thread?
pitch diameter
major diameter
minor diameter
root
minor diameter
Which G code specifies the one-pass canned cycle for threading?
G32
G99
G92
G76
G92
What word command is commonly used to program geometry offset entries?
G10
T0101
G20
G40
G10
Parameters that could affect your thread on a CNC turning center include:
number of spring passes parameter
minimum pass depth parameter
last pass depth parameter
all of the above
all of the above
Name one thing that could cause a machined thread's pitch to vary or come out wrong.
Any of the following are acceptable answers.
- exceeding the machine's maximum feed rate
- insufficient approach distance
- insufficient escape distance
What is the term for the distance from one thread crest to the next thread crest?
pitch
thread angle
root
lead
pitch
Which G code specifies the multiple repetitive cycle for threading?
G32
G99
G76
G92
G76
On a qualified tool holder for a CNC turning center, where does the tooling origin correspond to in both X and Z axes?
the turret face
What type of thread forms are popular with applications involving the flow of gasses or liquids when leakage must be prevented?
tapered thread forms
In a one-line G76 command, which letter address word specifies the taper amount?
F
K
D
I
I
How do you calculate thread depth?
Answer Key
You calculate thread depth by subtracting the thread's minor diameter from its major diameter and dividing the result by 2 (Major ∅ − Minor ∅) ÷ 2
In a one-line G76 command, which letter address word specifies the first pass depth?
F
K
I
D
D
When using G10 to program geometry offset values, where do you include the G10 since this command is only required once?
- after the M30 that ends the machining program
When programming geometry offset values, what does the L word specify?
- the kind of data you are entering
Once you have touched off a tool, you type MX and a value in the geometry offset. What does MX stand for?
measure X
Name the 3 threading infeed methods.
- compound infeed
- radial infeed
- alternating compound infeed (also called incremental infeed)
In a one-line G76 command, which letter address word specifies the thread's lead?
I
F
K
D
F
Provide the definition of a vector.
A vector is a quantity having magnitude and direction.
Which G code should you use for tapping?
G92
G01
G76
G32
G32
Name 3 factors that determine handedness when machining a thread on a CNC turning center.
- handedness of the cutting tool
- spindle direction (forward or reverse)
- motion direction during each threading pass