clw =true;  // direction of spiral
p = 1.4;      // pitch of thread spiral 
n = 12;     // number of 'threads'
res = 100;  // number of 'steps' in circle
db = 26.9;     // diam of os of spiral at base
dt = 24.91;     // diam of spiral at top
// for non tapered thread, make dt =db;
d = 1;       // diam of 'wire'

////////////////////


use <whitprof.scad>

t = n*res;    //total number of steps
s = (res/360)*db/2; // width of profile
v = p/res;   // vertical shift per inc of rotation
//a = 360/res; // angle per step
a=clw==true ?  +360/res  : -360/res;

module profile1(){
  circle (d,$fn=3);
  translate([-2.72,0])
  square([5-d/2,d*1.72],true);
    //circle (d=d)  // whatever 'profile' you like
   // square(d,true);

}


module profile(){
  translate ([-0.160083*p,p/2])
    rotate([0,0,-86.6])
     prof(p);
      translate([-2.5,0])
      square([5.5-d/2,p],true);
}



module xsec(v){
  $fn=80;
    s=(res/360)*v;
    translate([v-(d/2),0,0])
    rotate([90,0,0])
    linear_extrude(s/2)
    profile();
}

module screw(){
for (i=[0:1:t]){
   k=db-(i*(db-dt)/t);
     translate([0,0,i*v])
     rotate([0,0,i*a])
     xsec(k/2);
  }
 }
 
 screw();
 
// remove above  line and uncomment below for tapered plug.
 
/*
 $fn=80;
 // make tapered threaded stop end

 intersection(){
    sphere(18.5); //
      difference(){
        union(){
         screw();
         cylinder (h=15,d=dt-5); // fill core
               }
      translate ([-50,-50,15])cube(100);  // cut off top
                  }

                  }
 // head 
   translate([0,0,-4.9])
    cube([db+5,db+5,10],true);
    cylinder(d=db+2,h=0.5);
*/