copincha/3--construir/mobiliario/bsp_thread_form.scad

//BSP_form();
//BSP_thread(pitch=25.4/14,dia=1.041*25.4,threads = 7,draw_inc=1000);


//**************************************************
//Horrible module to rotate a slice
//**************************************************

module BSP_thread(pitch=1.814,dia=18.613,threads = 1,draw_inc=360){

a_move = (360*threads)/draw_inc;

function x_move(i) = dia-(sin(i*a_move)*dia);
function y_move(i) = dia+(cos(i*a_move)*dia);
function z_move(i) = i * (pitch*threads)/draw_inc;
function z_rot(i) = 90 + (i * a_move);

union(){
for(i = [0:draw_inc])
{
echo(i,x_move(i),y_move(i),z_move(i));
translate([x_move(i),
			y_move(i),
			z_move(i)])

rotate([90,
		0,
		z_rot(i)])
linear_extrude(height = 2.2*(threads*3.142*dia)/draw_inc, 
				center = true, 
				convexity = 10, 
				twist = 0, 
				$fn = 100)

				BSP_form(P=pitch,D=dia,AA=55);

	}
}

}

//**************************************************
//Flat Thread Form For Extrusion
//**************************************************

module BSP_form( male=true, P=1.814,D=18.613,AA=55,$fn=30){
/*	male, is the form a male of female thread
	P, Pitch
	D, diameter
	AA, form angle
*/

tr = P * 0.137329;		//end radius
th = P*0.640327;		//thread form height
AA2 = AA/2;  			//functional angle

tvv = cos(AA2)*tr; 	//height of tangent point
thv = sin(AA2)*tr;		//horizontal of tanget
cc = (th)-tr; 		//end radius circle centre
tc = cc + thv;
thh = tan(AA2)*th;
tbh = thh + tvv;
//echo(tvv,thv,tc,thh);
//**************************************************
//rotate([90,0,0])
union(){
	translate([cc,0])circle(r=tr);
	polygon(points = [ [0, tbh],
						[tc, tvv],
						[tc, -tvv],
						[0, -tbh]]);
	}
}