Arrow of Light – Keyhole

To hang the plaques, I’m going to cut a keyhole on the back.  This is done with a keyhole cutter.

The cutting process works like this:

  1. The cutter does rapid movement to position itself over the hole location
  2. It plunges into the material to the desired depth.
  3. It moves forward toward the top of the plaque to create the keyway.
  4. It stops and moves back to the hole.
  5. It rapids upward clear of the stock.

HeeksCNC doesn’t have an operation like this but it’s fairly simple to accomplish anyway.

I started by adding a sketch with a single line segment to represent the key way.  I selected the sketch and added a profile operation.  I set the parameters so the cutter would cut ‘on’ the line and at the depth I needed for the bottom of the hole (-9 mm).  In the resulting path, steps 1, 2, and 3 are represented, but then the cutter moves up to clear.

All we need to do is hand edit the g-code to add rapid back to the previous location before ascending.

G90(Absolute Coordinates)
G21(Metric Values)
G17(Select XY Plane)
G54(Select Relative Coordinate System)
(tool change to 1/4″ carbide 2 flute endmill)
G01Z-9.000F593.970 (descend into the material)
G01X165.048Y304.802F500.000  (forward cut)
G00Z5.000 (retract out)

All we need to do is add this line before the retract:


Now the backplot (shown in emc2) looks like this:

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