creating custom thread....

[adrianschlatter]

creating custom thread....

[nohkumado]

ok, finally understood some part of it... Rrot is the inner radius of the thread and just afterwards there is Dsupport as diameter of the inner circle of the thread.... and that leaves me puzzled? why the need to specify both? since one is 1/2 of the other??

[nohkumado]

well....
now it displays in prerendering as it should but doesn't compile:
ERROR: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion violation! Expr: e->incident_sface() != SFace_const_handle() File: /usr/include/CGAL/Nef_S2/SM_const_decorator.h Line: 330

aussenradius = 50;
19 MY_THREAD_TABLE = [
20 ["M48p8-ext", [8, 19, 38, [[0, -3.8], [0, 3.8], [5, 0.3], [5, -0.3]]]],
21 ["M48p8-int", [8, -23, 45.0, [[0, 4], [0, -4], [4.9, -0.6], [4.9, 0.6]]]],
22 ];
28 nut("M48p8", h = aussenradius/2, Douter = aussenradius,table=MY_THREAD_TABLE);

what's going wrong?

[adrianschlatter]

I think you'll find the help you need in the docs: Read the markdown (.md files) in the docs subdir. The specification of the THREAD_TABLE contents is here.

[nohkumado]

neat ev a pointer from the first page on it could be helpful?

still..... i don't get it to work for the -int....
schraubend = 40;
tol =0.5;

MY_THREAD_TABLE = [ 
  ["M48p8-ext", [8, .99*(schraubend-tol)/2, schraubend-tol,    [[0, -3.8], [0, 3.8], [5, 0.3], [5, -0.3]]]],
  ["M48p8-int", [8, 1.02*(schraubend+tol)/2, (schraubend+tol), [[0, 4], [0, -4], [4.9, -0.6], [4.9, 0.6]]]],  
];
    specs = thread_specs("M48p8-int", table=MY_THREAD_TABLE);
    P = specs[0]; Dsupport = specs[2];
    H = (26) * P ;
    turns = (schraubend+tol)/P-1;
  thread("M48p8-int", turns =  turns, table=MY_THREAD_TABLE);

//difference()
//{
cylinder(d=1.5*schraubend, h=25);
// translate([0,0,-1])cylinder(d=Dsupport, h=27);
//}

as soon as i add the cylinder, it won't compile with the CGAL Error?
any idea?

[adrianschlatter]

Looking at the internal thread spec, I believe there will be a problem because the thread will just touch itself after one full turn ([0, 4] to [0, -4] spans a distance of 8, the pitch is 8 as well). [0, 3.9], [0, -3.9] would avoid that problem.