Bolt Circle
or PDC
General
"0 starts at"
This allows you to set the orientation according to your
drawing, design or plan specifications.
"coordinates"
This allows you to set the results to match your X - Y
coordinate system of your machinery or digital readout.
"Incrument"
You would normally set this to clockwise however if you have to drill from
the reverse side then anti
clockwise gives you the
mirror, this becomes important when the first hole is not at 0
degrees or when you are drilling less holes than are in the PDC.
"X and Y origin"
Normally the X and Y origin (datum, zero point ore
reference point) is at the centre of the PDC. When the origin is
offset from the circle centre then you can give the offset. The
offset can be negative or positive. If left blank then 0 is
assumed.
Normal PDC
The holes are evenly angularly spaced based on
360 / number of holes.
"Angle of first
hole"
Normally the first hole is drilled at 0 degrees, where
you need to first hole to be at some other angle then you can
specify that angle, this may be positive or negative. If left
blank then 0 is assumed.
Arc PDC
The holes are
angulary evenly spaced within the arc specified by Start angle and End Angle.
The angular spacing is based on arc / number of holes.