diff --git a/CFTubes/common.scad b/CFTubes/common.scad
index e83ac44..88e82a2 100644
--- a/CFTubes/common.scad
+++ b/CFTubes/common.scad
@@ -137,9 +137,10 @@ module TrussRodGeneric(length, tolerance, stages, taper_l = 1.5, taper_extra = 1
 	rot = [-90, 180, 0];
 
 	module squircle(d, h, w) {
+		sq_h = max(h-d, epsilon);
 		render() hull() {
 			circle(d = d);
-			translate([-w/2, h - d/2 - epsilon]) square([w, epsilon]);
+			translate([-w/2, h - d/2 - sq_h]) square([w, sq_h]);
 		}
 	}
 
@@ -206,7 +207,7 @@ module TrussRodSingleAction(length = 460, tolerance = 0, taper_l = 1.5, taper_ex
 	base_h = 8.1 + tolerance;
 
 	// nut?
-	stage2_d = 7.0 + 0.2 + tolerance;
+	stage2_d = 7.0 + 0.8 + tolerance;
 	stage2_w = base_w;
 	stage2_h = base_h + (stage2_d - base_d);
 	stage2_l = 44 + tolerance;