diff --git a/js/kiri-print.js b/js/kiri-print.js
index bd286906..8b0cc355 100644
--- a/js/kiri-print.js
+++ b/js/kiri-print.js
@@ -645,7 +645,7 @@ var gs_kiri_print = exports;
 
                     // anti-backlash on longer move
                     if (antiBacklash && dist > retractDist) {
-                        addOutput(preout, p1.add({x:2,y:-2,z:0}), 0, moveSpeed);
+                        addOutput(preout, p1.add({x:antiBacklash,y:-antiBacklash,z:0}), 0, moveSpeed);
                     }
 
                     // bridge ends of fill when they're close together
diff --git a/js/kiri.js b/js/kiri.js
index 6e4f1568..80a737bc 100644
--- a/js/kiri.js
+++ b/js/kiri.js
@@ -308,7 +308,7 @@ self.kiri.license = exports.LICENSE;
                 outputShortFactor: 0.2,
                 outputFinishFactor: 0,
                 detectThinWalls: false,
-                antiBacklash: false,
+                antiBacklash: 2,
                 outputCooling: true,
 
                 // --- LASER ---
@@ -2496,7 +2496,7 @@ self.kiri.license = exports.LICENSE;
             outputShortDistance: UC.newInput("short segment", {title:"segment length cutoff\nfor short segments\nin millimeters", bound:UC.bound(0,200), convert:UC.toFloat, modes:FDM}),
             outputShortFactor: UC.newInput("short factor", {title:"max speed reduction factor\nfor short segments\nas % of print speed", bound:UC.bound(0.05,1), convert:UC.toFloat, modes:FDM}),
             outputFinishFactor: UC.newInput("finish factor", {title:"% of nozzle diameter to\nshorten finish path by\nvalues of 0-1", bound:UC.bound(0.0,1), convert:UC.toFloat, modes:FDM}),
-            antiBacklash: UC.newBoolean("anti-backlash", onBooleanClick, {title: "use micro-movements to cancel\nbacklash during fills", modes:FDM}),
+            antiBacklash: UC.newInput("anti-backlash", {title: "use micro-movements to cancel\nbacklash during fills\nin millimeters", bound:UC.bound(0,3), convert:UC.toInt, modes:FDM}),
             //detectThinWalls: UC.newBoolean("thin wall fill", onBooleanClick, {title: "detect and fill thin openings\nbetween shells walls", modes:FDM})
         });
 
diff --git a/js/moto-ui.js b/js/moto-ui.js
index b689e494..2e4451ef 100644
--- a/js/moto-ui.js
+++ b/js/moto-ui.js
@@ -87,6 +87,7 @@ var gs_moto_ui = exports;
 
     function toInt() {
         var nv = this.value !== '' ? parseInt(this.value) : null;
+        if (isNaN(nv)) nv = 0;
         if (nv !== null && this.bound) nv = this.bound(nv);
         this.value = nv;
         return nv;
@@ -101,6 +102,7 @@ var gs_moto_ui = exports;
 
     function bound(low,high) {
         return function(v) {
+            if (isNaN(v)) return low;
             return v < low ? low : v > high ? high : v;
         };
     }