diff --git a/src/kiri-mode/cam/client.js b/src/kiri-mode/cam/client.js
index a73732e6..4b1bf706 100644
--- a/src/kiri-mode/cam/client.js
+++ b/src/kiri-mode/cam/client.js
@@ -258,7 +258,7 @@ CAM.init = function(kiri, api) {
         "selection.rotate"
     ], updateStock);
 
-    // invalidate trace ops on scale or rotate
+    // invalidate trace and drill ops on scale or rotate
     api.event.on([
         "selection.scale",
         "selection.rotate"
@@ -268,6 +268,9 @@ CAM.init = function(kiri, api) {
             if (op.type === 'trace' && !flipping) {
                 op.areas = {};
             }
+            else if( op.type === 'drill' && !flipping){
+                op.drills = {};
+            }
         }
     });
 
@@ -401,7 +404,7 @@ CAM.init = function(kiri, api) {
 
     func.opAddDrill = () => {
         let rec = popOp.drill.new();
-        rec.drills = { /* widget.id: [ drills... ] */ };
+        rec.drills = {  };
         func.opAdd(rec);
     };
 
@@ -1245,11 +1248,10 @@ CAM.init = function(kiri, api) {
                     alert = api.show.alert("Some holes are shadowed by part and are not shown.");
                 }
                 centers = centers ?? []
-                //flattened list of all hole centers and if they are selected
+                // list of all hole centers and if they are selected
                 kiri.api.widgets.for(widget => {
                     const {holes} = centers.find(center=>center.id = widget.id)
-
-                    console.log(holes)
+                    // console.log(holes)
                     if (!holes.length) unselectHoles(holes);
                     holes.forEach(hole => {
                         createHoleMesh(widget, hole)
@@ -1403,12 +1405,12 @@ CAM.init = function(kiri, api) {
             func.traceDone();
         }
         unselectTraces(widget);
-        if (flipping) {
-            return;
-        }
         if (holeSelOn) {
             func.selectHolesDone();
         }
+        if (flipping) {
+            return;
+        }
         func.clearHolesRec(widget)
         if (x || y) {
             clearTabs(widget);
@@ -1778,8 +1780,8 @@ CAM.init = function(kiri, api) {
         lift:    'camDrillLift',
         mark:    'camDrillMark',
         thru:    'camDrillThru',
+
     })
-    
     drillOp.inputs = {
         tool:     UC.newSelect(LANG.cc_tool, {}, "tools"),
         sep:      UC.newBlank({class:"pop-sep"}),
diff --git a/src/kiri-mode/cam/driver.js b/src/kiri-mode/cam/driver.js
index f10b3783..12882077 100644
--- a/src/kiri-mode/cam/driver.js
+++ b/src/kiri-mode/cam/driver.js
@@ -167,7 +167,7 @@ kiri.load(api => {
             // const fresh = widgets.filter(widget => CAM.traces(settings, widget, single));
             send.done(kiri.codec.encode(fresh.map(widget => { return {
                 id: widget.id,
-                holes: widget.holes,
+                holes: widget.drills,
                 shadowed:widget.shadowedDrills
             } } )));
         }
diff --git a/src/kiri-mode/cam/slice.js b/src/kiri-mode/cam/slice.js
index 5624940f..aae4bfac 100644
--- a/src/kiri-mode/cam/slice.js
+++ b/src/kiri-mode/cam/slice.js
@@ -474,12 +474,14 @@ CAM.holes = async function(settings, widget, diam) {
         .map(kv => parseFloat(kv).round(5))
         .filter(z => z !== null)
     )]
+    let individual = (diam <= 0);
+
+    diam = individual ? 1 : diam; // sets default diameter when select individual used
+
     let centerDiff = diam * 0.1,
         area = (diam/2) * (diam/2) * Math.PI,
-        areaDelta =  area * 0.05,
-        drills = [],
-        slices = [],
-        individual = (diam <= 0);
+        circles = [],
+        slices = [];
 
     function onEach(slice) {
         slices.push(slice);
@@ -499,38 +501,70 @@ CAM.holes = async function(settings, widget, diam) {
             for (let poly of inner) {
                 let center = poly.calcCircleCenter();
                 center.area = poly.area();
+                center.overlapping = [center]
+                center.depth = 0;
                 // console.log("center",center)
-                center.selected = (!individual && poly.circularity() >= 0.985 && Math.abs(center.area - area) <= areaDelta );
+                if ( poly.circularity() < 0.985 ){
+                    // if not circular, don't add to holes
+                    continue;
+                }
                 if (center.isInPolygon(slice.shadow)) {
                     // if shadowed, don't add, and inform client
                     shadowedDrills = true;
                     continue;
                 }
                 let overlap = false;
-                for (let [i,drill] of drills.entries()) {
-                    let dist = drill.distTo2D(center)
-                    //if on the same xy point, and both have the same selection value
-                    if (dist <= centerDiff && drill.selected == center.selected) {  
-                        // console.log("overlap",center,drill);
-                        if(center.z > drill.z) { //if current is higher than old
-                            drills[i] = center; //replace with top point
-                            drills[i].depth = center.z-drill.z
-                        }else if(center.z <= drill.z-drill.depth){// if current is lower or same as old
-                            drills[i].depth = drill.z-center.z
-                        }
+                for (let [i,circle] of circles.entries()) {
+                    let dist = circle.distTo2D(center)
+
+                    // //if on the same xy point, 
+                    if (dist <= centerDiff ) {
+                        
+                        // console.log("overlap",center,circle);
+                        circle.overlapping.push(center);
                         // if overlapping, don't add and continue
                         overlap = true;
                         continue;
                     }
                 }
-                center.depth = 0;
-                if(!overlap) drills.push(center);
+                if (!overlap) circles.push(center);
             }
         }
     }
+
+    let drills = []
+
+    for (let c of circles) {
+        let overlapping = c.overlapping
+        .sort((a,b) => b.z - a.z)
+
+        let last = overlapping.shift();
+        while (overlapping.length) {
+            let circ = overlapping.shift();
+            let aveArea = (circ.area + last.area) / 2;
+            let areaDelta = Math.abs(circ.area -last.area)
+            if (areaDelta < aveArea * 0.05){ // if area delta less than 5% of average area
+              //keep top circle selected
+              last.depth = last.z - circ.z;
+            }else{ // if not the same area
+              //push and move on
+              drills.push(last);
+              last = circ;
+            }
+        }
+        if (last.depth != 0) drills.push(last) //add last circle
+    }
+
+    drills.forEach( h=>{
+        delete h.overlapping //for encoding
+        h.selected = (!individual && Math.abs(h.area - area) <= area * 0.05 ); //for same size selection
+    }) 
+
+    // console.log("unfiltered circles",circles)
+    // console.log("drills",drills)
     drills = drills.filter(drill => drill.depth > 0)
     widget.shadowedDrills = shadowedDrills
-    widget.holes = drills;
+    widget.drills = drills;
     return drills;
 }