diff --git a/bearings.scad b/bearings.scad
new file mode 100644
index 0000000..0467ae3
--- /dev/null
+++ b/bearings.scad
@@ -0,0 +1,9 @@
+//Todo: placeholder; should generate standard + cusom bearing mounting holes
+module bearing_hole(outer_radius, hole=true, mochup=true)
+{
+	union()
+	{
+		if (mochup==true) %translate([0,0,-1.5])cylinder(r=outer_radius,h=3);
+		if (hole==true) circle(r=outer_radius);
+	}
+}
diff --git a/gears.scad b/gears.scad
new file mode 100644
index 0000000..d264912
--- /dev/null
+++ b/gears.scad
@@ -0,0 +1,171 @@
+//test
+//	gear(number_of_teeth=11,diametral_pitch=17);
+translate([(51+17)*200/360+1.15,0]) rotate(-0.02)
+	gear(number_of_teeth=51,circular_pitch=200);
+	gear(number_of_teeth=17,circular_pitch=200);
+	translate([-50,0]) gear(number_of_teeth=17,diametral_pitch=2);
+
+//test();
+
+module test()
+{
+for (i=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15])
+{
+	//echo(polar_to_cartesian([involute_intersect_angle( 0.1,i) , i ]));
+	translate(polar_to_cartesian([involute_intersect_angle( 0.1,i) , i ])) circle($fn=15, r=0.5);
+
+	//translate( involute_intersection_point(0.1,i,0) ) circle($fn=15, r=0.5);
+}
+}
+
+
+//	circular_pitch = pitch_diameter*180/ number_of_teeth;
+
+
+// Geometry Sources:
+//	http://www.cartertools.com/involute.html
+//	gears.py (inkscape extension: /usr/share/inkscape/extensions/gears.py)
+// Usage:
+//	Diametral pitch: Number of teeth per unit length.
+//	Circular pitch: Length of the arc from one tooth to the next
+//	Clearance: Radial distance between top of tooth on one gear to bottom of gap on another.
+
+module gear(number_of_teeth,
+		circular_pitch=false, diametrial_pitch=false,
+		pressure_angle=20, clearance = 0)
+{
+	if (circular_pitch==false && diametrical_pitch==false) echo("MCAD ERROR: gear module needs either a diametrical_pitch or circular_pitch");
+	
+	//Convert diametrial pitch to our native circular pitch
+	circular_pitch = (circular_pitch!=false?circular_pitch:180/diametral_pitch);
+	
+	// Pitch diameter: Diameter of pitch circle.
+	pitch_diameter  =  number_of_teeth * circular_pitch / 180;
+	pitch_radius = pitch_diameter/2;
+	
+	// Base Circle
+	base_diameter = pitch_diameter*cos(pressure_angle);
+	base_radius = base_diameter/2;
+
+	// Diametrial pitch: Number of teeth per unit length.
+	pitch_diametrial = number_of_teeth / pitch_diameter;
+
+	// Addendum: Radial distance from pitch circle to outside circle.
+	addendum = 1/pitch_diametrial;
+	
+	//Outer Circle
+	outer_radius = pitch_radius+addendum;
+	outer_diameter = outer_radius*2;
+	
+	// Dedendum: Radial distance from pitch circle to root diameter
+	dedendum = addendum + clearance;
+
+	// Root diameter: Diameter of bottom of tooth spaces.
+	root_radius = pitch_radius-dedendum;
+	root_diameter = root_radius * 2;
+	
+	half_thick_angle = 360 / (4 * number_of_teeth);
+	echo(half_thick_angle);
+	
+	union()
+	{
+		rotate(half_thick_angle) circle($fn=number_of_teeth*2, r=root_radius*1.001);
+		
+		for (i= [1:number_of_teeth])
+		//for (i = [0])
+		{
+			rotate([0,0,i*360/number_of_teeth])
+			{
+				involute_gear_tooth(
+					pitch_radius = pitch_radius,
+					root_radius = root_radius,
+					base_radius = base_radius,
+					outer_radius = outer_radius,
+					half_thick_angle = half_thick_angle);
+			}
+		}
+	}
+}
+
+
+module involute_gear_tooth(
+					pitch_radius,
+					root_radius,
+					base_radius,
+					outer_radius,
+					half_thick_angle
+					)
+{
+	pitch_to_base_angle  = involute_intersect_angle( base_radius, pitch_radius );
+	
+	outer_to_base_angle = involute_intersect_angle( base_radius, outer_radius );
+
+	//echo(base_radius);
+	//echo(outer_radius);
+	//echo(outer_to_base_angle);
+	echo(acos(base_radius/pitch_radius));
+
+	base1 = 0 - pitch_to_base_angle - half_thick_angle;
+	pitch1 = 0 - half_thick_angle;
+	outer1 = outer_to_base_angle - pitch_to_base_angle - half_thick_angle;
+	
+	b1 = polar_to_cartesian([ base1, base_radius ]);
+	p1 = polar_to_cartesian([ pitch1, pitch_radius ]);
+	o1 = polar_to_cartesian([ outer1, outer_radius ]);
+	
+	b2 = polar_to_cartesian([ -base1, base_radius ]);
+	p2 = polar_to_cartesian([ -pitch1, pitch_radius ]);
+	o2 = polar_to_cartesian([ -outer1, outer_radius ]);
+	
+	// ( root_radius > base_radius variables )
+		pitch_to_root_angle = pitch_to_base_angle - involute_intersect_angle(base_radius, root_radius );
+		root1 = pitch1 - pitch_to_root_angle;
+		root2 = -pitch1 + pitch_to_root_angle;
+		r1_t =  polar_to_cartesian([ root1, root_radius ]);
+		r2_t =  polar_to_cartesian([ -root1, root_radius ]);
+	
+	// ( else )
+		r1_f =  polar_to_cartesian([ base1, root_radius ]);
+		r2_f =  polar_to_cartesian([ -base1, root_radius ]);
+	
+	if (root_radius > base_radius)
+	{
+		echo("true");
+		polygon( points = [
+			r1_t,p1,o1,o2,p2,r2_t
+		], convexity = 3);
+	}
+	else
+	{
+		polygon( points = [
+			r1_f, b1,p1,o1,o2,p2,b2,r2_f
+		], convexity = 3);
+	}
+	
+}
+
+
+
+// Finds the angle of the involute about the base radius at the given distance (radius) from it's center.
+//source: http://www.mathhelpforum.com/math-help/geometry/136011-circle-involute-solving-y-any-given-x.html
+
+function involute_intersect_angle(base_radius, radius) = sqrt( pow(radius/base_radius,2) - 1);
+
+
+
+// Polar coord [angle, radius] to cartesian coord [x,y]
+
+function polar_to_cartesian(polar) = [
+	polar[1]*cos(polar[0]),
+	polar[1]*sin(polar[0])
+];
+
+
+// == LEGACY ==
+// Finds the intersection of the involute about the base radius with a cricle of the given radius in cartesian coordinates [x,y].
+
+//function involute_intersection_point(base_radius, radius, zero_angle) = polar_to_cartesian([  involute_intersect_angle(base_radius, radius)-zero_angle  ,  radius  ]);
+
+//function rotation_matrix(degrees) = [ [cos(degrees), -sin(degrees)] , [sin(degrees), cos(degrees)] ];
+
+//function involute_intersect_angle(base_radius, radius) = sqrt( pow(radius,2) - pow(base_radius,2) ) / base_radius - acos(base_radius / radius);
diff --git a/math.scad b/math.scad
new file mode 100644
index 0000000..ca1f211
--- /dev/null
+++ b/math.scad
@@ -0,0 +1,4 @@
+PI = 3.14159;
+
+// translates a imperial measurement in inches to meters
+mm_per_inche =25.4;
diff --git a/motors.scad b/motors.scad
new file mode 100644
index 0000000..745b1ed
--- /dev/null
+++ b/motors.scad
@@ -0,0 +1,92 @@
+include <math.scad>
+
+
+//generates a motor mount for the specified nema standard #.
+module stepper_motor_mount(nema_standard,slide_distance=0, mochup=true)
+{
+	//dimensions from:
+	// http://www.numberfactory.com/NEMA%20Motor%20Dimensions.htm
+	if (nema_standard == 17)
+	{
+		_stepper_motor_mount(
+			motor_shaft_diameter = 0.1968*mm_per_inche,
+			motor_shaft_length = 0.945*mm_per_inche,
+			pilot_diameter = 0.866*mm_per_inche,
+			pilot_length = 0.80*mm_per_inche,
+			mounting_bolt_circle = 1.725*mm_per_inche,
+			bolt_hole_size = 3.5,
+			bolt_hole_distance = 1.220*mm_per_inche,
+			slide_distance = slide_distance,
+			mochup = mochup);
+	}
+	if (nema_standard == 23)
+	{
+		_stepper_motor_mount(
+			motor_shaft_diameter = 0.250*mm_per_inche,
+			motor_shaft_length = 0.81*mm_per_inche,
+			pilot_diameter = 1.500*mm_per_inche,
+			pilot_length = 0.062*mm_per_inche,
+			mounting_bolt_circle = 2.625*mm_per_inche,
+			bolt_hole_size = 0.195*mm_per_inche,
+			bolt_hole_distance = 1.856*mm_per_inche,
+			slide_distance = slide_distance,
+			mochup = mochup);
+	}
+	
+}
+
+
+//inner mehod for creating a stepper motor mount of any dimensions
+module _stepper_motor_mount(
+	motor_shaft_diameter,
+	motor_shaft_length,
+	pilot_diameter,
+	pilot_length,
+	mounting_bolt_circle,
+	bolt_hole_size,
+	bolt_hole_distance,
+	slide_distance = 0,
+	motor_length = 40, //arbitray - not standardized
+	mochup
+)
+{
+	union()
+	{
+	// == centered mount points ==
+	//mounting circle inset
+	translate([0,slide_distance/2,0]) circle(r = pilot_diameter/2);
+	square([pilot_diameter,slide_distance],center=true);
+	translate([0,-slide_distance/2,0]) circle(r = pilot_diameter/2);
+
+	//todo: motor shaft hole
+	
+	//mounting screw holes
+	for (x = [-1,1])
+	{
+		for (y = [-1,1])
+		{
+			translate([x*bolt_hole_distance/2,y*bolt_hole_distance/2,0])
+			{
+				translate([0,slide_distance/2,0]) circle(bolt_hole_size/2);
+				translate([0,-slide_distance/2,0]) circle(bolt_hole_size/2);
+				square([bolt_hole_size,slide_distance],center=true);
+			}
+		}
+	}
+	// == motor mock-up ==
+	//motor box
+	if (mochup == true)
+	{
+		%translate([0,0,-5]) cylinder(h = 5, r = pilot_diameter/2);
+		%translate(v=[0,0,-motor_length/2])
+		{
+			cube(size=[bolt_hole_distance+bolt_hole_size+5,bolt_hole_distance+bolt_hole_size+5,motor_length], center = true);
+		}
+		//shaft
+		%translate(v=[0,0,-(motor_length-motor_shaft_length-2)/2])
+		{
+			%cylinder(r=motor_shaft_diameter/2,h=motor_length+motor_shaft_length--1, center = true);
+		}
+	}
+	};
+}
\ No newline at end of file
diff --git a/nuts_and_bolts.scad b/nuts_and_bolts.scad
new file mode 100644
index 0000000..4311665
--- /dev/null
+++ b/nuts_and_bolts.scad
@@ -0,0 +1,179 @@
+//testNutsAndBolts();
+
+module testNutsAndBolts()
+{
+	$fn = 360;
+	translate([0,15])nutHole(3, proj=2);
+	boltHole(3, length= 30, proj=2);
+}
+
+MM = "mm";
+INCH = "inch"; //Not yet supported
+
+//Based on: http://www.roymech.co.uk/Useful_Tables/Screws/Hex_Screws.htm
+METRIC_NUT_AC_WIDTHS = 
+[
+	-1, //0 index is not used but reduces computation
+	-1,
+	-1,
+	6.40,//m3
+	8.10,//m4
+	9.20,//m5
+	11.50,//m6
+	-1,
+	15.00,//m8
+	-1,
+	19.60,//m10
+	-1,
+	22.10,//m12
+	-1,
+	-1,
+	-1,
+	27.70,//m16
+	-1,
+	-1,
+	-1,
+	34.60,//m20
+	-1,
+	-1,
+	-1,
+	41.60,//m24
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	53.1,//m30
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	63.5//m36
+];
+METRIC_NUT_THICKNESS =
+[
+	-1, //0 index is not used but reduces computation
+	-1,
+	-1,
+	2.40,//m3
+	3.20,//m4
+	4.00,//m5
+	5.00,//m6
+	-1,
+	6.50,//m8
+	-1,
+	8.00,//m10
+	-1,
+	10.00,//m12
+	-1,
+	-1,
+	-1,
+	13.00,//m16
+	-1,
+	-1,
+	-1,
+	16.00//m20
+	-1,
+	-1,
+	-1,
+	19.00,//m24
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	24.00,//m30
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	29.00//m36
+];
+
+COURSE_METRIC_BOLT_MAJOR_THREAD_DIAMETERS = 
+[//based on max values
+	-1, //0 index is not used but reduces computation
+	-1,
+	-1,
+	2.98,//m3
+	3.978,//m4
+	4.976,//m5
+	5.974,//m6
+	-1,
+	7.972,//m8
+	-1,
+	9.968,//m10
+	-1,
+	11.966,//m12
+	-1,
+	-1,
+	-1,
+	15.962,//m16
+	-1,
+	-1,
+	-1,
+	19.958,//m20
+	-1,
+	-1,
+	-1,
+	23.952,//m24
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	29.947,//m30
+	-1,
+	-1,
+	-1,
+	-1,
+	-1,
+	35.940//m36
+];
+
+module nutHole(size, units=MM, tolerance = +0.0001, proj = -1)
+{
+	//takes a metric screw/nut size and looksup nut dimensions
+	radius = METRIC_NUT_AC_WIDTHS[size]/2+tolerance;
+	height = METRIC_NUT_THICKNESS[size]+tolerance;
+	if (proj == -1)
+	{
+		cylinder(r= radius, h=height, $fn = 6, center=[0,0]);
+	}
+	if (proj == 1)
+	{
+		circle(r= radius, $fn = 6);
+	}
+	if (proj == 2)
+	{
+		translate([-radius/2, 0])
+			square([radius*2, height]);
+	}
+}
+
+module boltHole(size, units=MM, length, tolerance = +0.0001, proj = -1)
+{
+	radius = COURSE_METRIC_BOLT_MAJOR_THREAD_DIAMETERS[size]/2+tolerance;
+//TODO: proper screw cap values
+	capHeight = METRIC_NUT_THICKNESS[size]+tolerance; //METRIC_BOLT_CAP_HEIGHTS[size]+tolerance;
+	capRadius = METRIC_NUT_AC_WIDTHS[size]/2+tolerance; //METRIC_BOLT_CAP_RADIUS[size]+tolerance;
+	
+	if (proj == -1)
+	{
+	translate([0, 0, -capHeight])
+		cylinder(r= capRadius, h=capHeight);
+	cylinder(r = radius, h = length);
+	}
+	if (proj == 1)
+	{
+		circle(r = radius);
+	}
+	if (proj == 2)
+	{
+		translate([-capRadius/2, -capHeight])
+			square([capRadius*2, capHeight]);
+		square([radius*2, length]);
+	}
+}
\ No newline at end of file