diff --git a/torx_drive.scad b/torx_drive.scad
new file mode 100644
index 0000000..57a35a6
--- /dev/null
+++ b/torx_drive.scad
@@ -0,0 +1,179 @@
+//////////////////////////////////////////////////////////////////////
+// Torx driver bits
+//////////////////////////////////////////////////////////////////////
+
+/*
+BSD 2-Clause License
+
+Copyright (c) 2017, Revar Desmera
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+use <transforms.scad>
+use <math.scad>
+
+
+function torx_outer_diam(size) = lookup(size, [
+	[  6,  1.75],
+	[  8,  2.40],
+	[ 10,  2.80],
+	[ 15,  3.35],
+	[ 20,  3.95],
+	[ 25,  4.50],
+	[ 30,  5.60],
+	[ 40,  6.75],
+	[ 45,  7.93],
+	[ 50,  8.95],
+	[ 55, 11.35],
+	[ 60, 13.45],
+	[ 70, 15.70],
+	[ 80, 17.75],
+	[ 90, 20.20],
+	[100, 22.40]
+]);
+ 
+
+function torx_inner_diam(size) = lookup(size, [
+	[  6,  1.27],
+	[  8,  1.75],
+	[ 10,  2.05],
+	[ 15,  2.40],
+	[ 20,  2.85],
+	[ 25,  3.25],
+	[ 30,  4.05],
+	[ 40,  4.85],
+	[ 45,  5.64],
+	[ 50,  6.45],
+	[ 55,  8.05],
+	[ 60,  9.60],
+	[ 70, 11.20],
+	[ 80, 12.80],
+	[ 90, 14.40],
+	[100, 16.00]
+]);
+ 
+
+function torx_depth(size) = lookup(size, [
+	[  6,  1.82],
+	[  8,  3.05],
+	[ 10,  3.56],
+	[ 15,  3.81],
+	[ 20,  4.07],
+	[ 25,  4.45],
+	[ 30,  4.95],
+	[ 40,  5.59],
+	[ 45,  6.22],
+	[ 50,  6.48],
+	[ 55,  6.73],
+	[ 60,  8.17],
+	[ 70,  8.96],
+	[ 80,  9.90],
+	[ 90, 10.56],
+	[100, 11.35]
+]);
+ 
+
+function torx_tip_radius(size) = lookup(size, [
+	[  6, 0.132],
+	[  8, 0.190],
+	[ 10, 0.229],
+	[ 15, 0.267],
+	[ 20, 0.305],
+	[ 25, 0.375],
+	[ 30, 0.451],
+	[ 40, 0.546],
+	[ 45, 0.574],
+	[ 50, 0.775],
+	[ 55, 0.867],
+	[ 60, 1.067],
+	[ 70, 1.194],
+	[ 80, 1.526],
+	[ 90, 1.530],
+	[100, 1.720]
+]);
+
+
+function torx_rounding_radius(size) = lookup(size, [
+	[  6, 0.383],
+	[  8, 0.510],
+	[ 10, 0.598],
+	[ 15, 0.716],
+	[ 20, 0.859],
+	[ 25, 0.920],
+	[ 30, 1.194],
+	[ 40, 1.428],
+	[ 45, 1.796],
+	[ 50, 1.816],
+	[ 55, 2.667],
+	[ 60, 2.883],
+	[ 70, 3.477],
+	[ 80, 3.627],
+	[ 90, 4.468],
+	[100, 4.925]
+]);
+
+
+module torx_drive2d(size) {
+	od = torx_outer_diam(size);
+	id = torx_inner_diam(size);
+	tip = torx_tip_radius(size);
+	rounding = torx_rounding_radius(size);
+	base = od - 2*tip;
+	$fn = quantup(segs(od/2),12);
+	difference() {
+		union() {
+			circle(d=base);
+			zring(n=2) {
+				hull() {
+					zring(n=3) {
+						translate([base/2,0,0]) {
+							circle(r=tip, $fn=$fn/2);
+						}
+					}
+				}
+			}
+		}
+		zring(n=6) {
+			zrot(180/6) {
+				translate([id/2+rounding,0,0]) {
+					circle(r=rounding);
+				}
+			}
+		}
+	}
+}
+
+
+
+module torx_drive(size, l=5, center=undef) {
+	linear_extrude(height=l, convexity=4, center=center) {
+		torx_drive2d(size);
+	}
+}
+
+
+
+// vim: noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap
+