# Tool Cutting Simulates a cylinder being cut into by another cylinder (e.g. an endmill).  The "cutting tool" follows a helical path around the stock.

```# cylinder dimensions
Diameter = 20
Length = 100

# cutter dimensions
CutterDiameter = 5

# angle to increase by on each pass of the cutter, in degrees
# must be a whole divisor of 180
StepAngle = 10

# total angle of cutting around the cylinder
TotalAngle = 1440

# starting distance from end of cylinder
StartX = 10

# create the cylinder
P = Part('Cylinder')
CylPlane = P.GetPlane('XY-Plane')

# create the planes
Planes = []
NumPlanes = 180 / StepAngle
for PlaneIndex in range(0, NumPlanes):
Angle = PlaneIndex * StepAngle
Pl = P.AddPlane('P' + str(Angle), P.GetPlane('YZ-Plane'), P.GetAxis('Z-Axis'), Angle)
Planes.append(Pl)
for PlaneIndex in range(0, NumPlanes):
Planes.append(Planes[PlaneIndex])
NumPlanes = NumPlanes * 2

# start of helix has no offset along cylinder
XStep = 0

# create circle sketches then extrude cut 'through all'
for Step in range(0, TotalAngle / StepAngle):
Angle = Step * StepAngle
NormalizedAngle = Angle % 360
XStep += (Angle * 0.001)
if NormalizedAngle < 90:
X = -(StartX + XStep)
Y = Diameter / 2.0
elif NormalizedAngle == 90:
X = -(Diameter / 2.0)
Y = -(StartX + XStep)
elif NormalizedAngle < 180:
X = (StartX + XStep)
Y = -(Diameter / 2.0)
elif NormalizedAngle < 270:
X = -(StartX + XStep)
Y = -(Diameter / 2.0)
elif NormalizedAngle == 270:
X = (Diameter / 2.0)
Y = -(StartX + XStep)
else:
X = (StartX + XStep)
Y = Diameter / 2.0
Sk = P.AddSketch('S' + str(Angle), Planes[Step % NumPlanes]) 