Modifying the Neck Pocket Toolpaths

There are two (2) neck pocket centerline toolpaths from the the STD Guitar CADD data set that we need to modify as required to fit the new body-to-neck pocket transition relief cut.

Let's begin on the lower horn transition:

Let's display only the relevant layers:

The STD Guitar CADD data set (only relevant layers shown above) contains two (2) layers of centerline toolpath data for the neck pocket:

CPB_0250-Neck_Pocket-Finish — Polylined 1/4" DIA Finish Path (purple)

CPB_0500-Neck_Pocket-Rough — Polylined 1/2" DIA Rough Path (magenta)

OK, first let's concentrate on the right hand (lower horn) side of the pocket and look at the 1/4" DIA finish pass.

First, Use the Modify -> Offset to offset the 0.063"R arc by 0.125" for a finish pass and an additional 0.015" for a roughing pass:

Note:

The arcs ending perpendicular to the line (black) drawn between the two arc centers confirm that our arcs are "Ogees" and that the cutter paths will be continuous (i.e., no unexpected cutter stops during CNC runtime).


Using small circles above and below the existing dual arc, we are able to isolate the old dual arc polyline and move it over to use as a guide.


Three Things To Do:

  1. Extend the "lower" trimmed toolpath up to the "finish" arc;
  2. Extend the "upper" trimmed toolpath down to the "rough" arc, trim off the left side of the "rough" arc, and use the Circle -> Tan-Tan-Radius to create a filleting arc ( R= 0.094") between the two objects; and
  3. Use the Circle -> 2 Points command along with the Object Snap -> End to create a transition between the rough and finish arcs.

After trimming, select the various objects and use the Modify -> Join command to reconnect the new geometry to the existing Rough centerline toolpath polyline.

Spot check

See how the geometry transitions exactly on the center-to-center line? That's a good Ogee.

Next, do the same thing to the 1/2" DIA cutter's roughing pass as shown above.

"Same thing, only different."

As the "Patrick Star" guitar body is basically a "single cut" profile, the left side (upper horn) body-to-neck pocket transitions are non-existent.

Consequentially, you just need to trim off the left side arcs and extend both the Finish and Rough centerline toolpaths up the entire left hand side of the neck pocket.

Easy Peasy...

Seriously, it doesn't get any easier that that.

However...

If your design has a double cut upper horn, what would the left hand (upper horn) body-to-neck pocket transition centerline toolpaths look like?

The cutter is coming up from the bottom.

The 0.094"R fillet(s) are just a suggestion but work for both the 1/4" DIA and the 1/2" DIA cutters.