difference(){

	union(){
		difference(){
			//basic shape
			union(){
				cube([13,26,45]);
				
				//end stop adapter 
				translate([10+1.4,13+5,45+3.9]){
					rotate([180,0,0]){
						cylinder(h=4,r1=3, r2=8);
					}
				}
			}
			
			//inner free space
			translate([-0.1,5,-5]){
				cube([7.1,16,75]);
			}
			
			//added space for free running belt
			translate([-0.1,21-4.5,-5]){
				cube([9.1,4.5,75]);
			}

		//avoiding collision between pushrod and carriage
		//also experiment with 15 deg angle on Z axis

		translate([6,26+2,0]){
			rotate([-12.4,0,0]) cube([16,10,12.4*2+10], center=true);
		}

		translate([6,5-7,0]){
			rotate([12.4,0,0]) cube([16,10,12.4*2+10], center=true);
		}

		//adjusting shape at the top
		translate([6,26+2,45]){
			rotate([12.4,0,0]) cube([16,10,12.4*2+10], center=true);
		}


		translate([6,-2,45]){
			rotate([-12.4,0,0]) cube([16,10,12.4*2+10], center=true);
		}
		
		}

		
		//RIGHT traxx mount 
		translate([6.5,-6.9,22.5]){
			rotate([-90,0,0]){
				union(){
					//cylinder(h=8,r1=2.5, r2=8);
					translate([0,0,6])cylinder(h=2,r1=4, r2=10, $fs=0.01);
					translate([0,0,2.9]) cylinder(h=8,r=4, $fs=0.01);
					cylinder(h=3,r1=2.5, r2=4, $fs=0.01);
				}
			}
		}

		//LEFT traxx mount 
		translate([6.5,32.9,22.5]){
			rotate([90,0,0]){
				//cylinder(h=8,r1=2.5, r2=8);
					translate([0,0,6])cylinder(h=2,r1=4, r2=10, $fs=0.01);
					translate([0,0,2.9]) cylinder(h=8,r=4, $fs=0.01);
					cylinder(h=3,r1=2.5, r2=4, $fs=0.01);
			}
		}
		
		
		union(){
			color("lightblue") hull(){
				translate([0.1,12,17]) rotate([0,90,0]) #cylinder(h=8.1, r=3.5, $fs=0.01);
				translate([0.1,12-3.5-1.5,17-5]) rotate([0,0,0]) #cube([8.1,2,2]);
			}
		}

		union(){
			color("blue") hull(){
				translate([0.1,11,7.5]) rotate([0,90,0]) cylinder(h=8.1, r=3.5, $fs=0.01);
				translate([0.1,7.5,0]) rotate([0,0,0]) cube([8.1,7,7]);
			}
		}

		union(){
			color("lightgreen") hull(){
				translate([0.1,12,28]) rotate([0,90,0]) #cylinder(h=8.1, r=3.5, $fs=0.01);
				translate([0.1,12-3.5-1.5,28+3.5]) rotate([0,0,0]) #cube([8.1,2,2]);
			}
		}

		union(){
			color("green") hull(){
				translate([0.1,11,37+1]) rotate([0,90,0]) cylinder(h=8.1, r=3.5, $fs=0.01);
				translate([0.1,7.5,37+1]) rotate([0,0,0]) cube([8.1,7,7]);
			}
}

	}

	//screw hole needs to move somewhere else
	//green
	translate([-10,11,37+1]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			translate([0,0,19.8]) #cylinder(d=6,h=13,$fs=0.01);
		}
	}
	//lightblue
	translate([-10,12,17]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			translate([0,0,19.8]) #cylinder(d=6,h=13,$fs=0.01);
		}
	}
	//blue
	translate([-10,11,7.5]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			translate([0,0,19.8]) #cylinder(d=6,h=13,$fs=0.01);
		}
	}
	//lightgreen
	translate([-10,12,28]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			translate([0,0,19.8]) #cylinder(d=6,h=13,$fs=0.01);
		}
	}


	//ensuring size of carriage
	translate([-13,-8,0]){
		cube([13,42,75]);
	}
	translate([13,-8,0]){
		cube([13,42,75]);
	}
 
	//traxx mounting screw channel
	translate([6.5,36,22.5]){
		rotate([90,0,0]){
			cylinder(d=3,h=46,$fs=0.01);
		}
	}

	//LEFT catch for traxx nut
	translate([6.5,21+7,22.5]){
		rotate([90,0,0]){
			cylinder(d=6.5,h=11,$fn=6);
		}
	}

	//RIGHT catch for traxx nut
	translate([6.5,9,22.5]){
		rotate([90,0,0]){
			cylinder(d=6.5,h=11,$fn=6);
		}
	}


	//button presser screws
	translate([10+1.4,13+5,54]){
		rotate([180,0,0]){
			#cylinder(d=3,h=25,$fs=0.01);
		}
	}

	//carriage mounting screws
	translate([-10,3,32.5]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			cylinder(d=6,h=13,$fs=0.01);
		}
	}
	
	//carriage mounting screws
	translate([-10,23,32.5]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			cylinder(d=6,h=13,$fs=0.01);
		}
	}

	//carriage mounting screws
	translate([-10,3,12.5]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			cylinder(d=6,h=13,$fs=0.01);
		}
	}
	


	//carriage mounting screws
	translate([-10,23,12.5]){
		rotate([0,90,0]){
			cylinder(d=3,h=36,$fs=0.01);
			cylinder(d=6,h=13,$fs=0.01);	
		}
	}
}