### Re: vise screw question

RW
Raymond West
Fri, Jul 22, 2022 10:11 AM

Here's a basic thread maker. You just need to draw the thread profile.

p=5; //pitch
t= 2.5; // depth of thread
od=10; //outside diam

/*
square([1,p]);  //Make 1 wide 'cos can't draw lines
square ([t+1,t]);
}

*/

polygon (points=[[0,0],[0,p],[1,p],[1,p-1],[t,1],[t,0]]);
}

module section(){
rotate([90,0,0])
linear_extrude(od/60)
{
square([od-t,p]);
translate ([od-t-1,0,0])
profile();
}
}

num=360*(l/p);
for (j=[0:1:num])
{
translate([0,0,j*p/360])
rotate([0,0,j])
section();
}

////end

square threads do not work with half nuts, acme is OK. If wood screw for
vice, the a buttress thread is best. Make the nut first and turn the
screw to fit.

You can play around with the linear_extrude and the for loop, to get
different resolution, but for wood and plastic, no need to sweat the
small stuff.

Try it for a short length first, it takes a while to f6.

On 21/07/2022 23:37, Bogdan Caramalac via Discuss wrote:

To unsubscribe send an email to discuss-leave@lists.openscad.org

GH
gene heskett
Fri, Jul 22, 2022 10:54 AM

On 7/22/22 06:14, Raymond West wrote:

Here's a basic thread maker. You just need to draw the thread profile.

p=5; //pitch
t= 2.5; // depth of thread
od=10; //outside diam

/*
square([1,p]);  //Make 1 wide 'cos can't draw lines
square ([t+1,t]);
}

*/

polygon (points=[[0,0],[0,p],[1,p],[1,p-1],[t,1],[t,0]]);
}

module section(){
rotate([90,0,0])
linear_extrude(od/60)
{
square([od-t,p]);
translate ([od-t-1,0,0])
profile();
}
}

num=360*(l/p);
for (j=[0:1:num])
{
translate([0,0,j*p/360])
rotate([0,0,j])
section();
}

////end

square threads do not work with half nuts, acme is OK. If wood screw
for vice, the a buttress thread is best. Make the nut first and turn
the screw to fit.

Or in the version I'm working on, I made the screw first, then used
the screw to design the nuts.  Accuracy of the buttress was somewhat
compromised by the choice of mill tool shape used to cut it, so the nut
was similarly
edited recursively to gain a good fit. Works well but I've not yet
actually put it
into a leg vise. I have two more parts to design and make before I assemble
the whole thing.

I used a 2 start buttress because its a vise screw but square would also
work
but its not as strong. The 2 start makes both half nuts identical.

You can play around with the linear_extrude and the for loop, to get
different resolution, but for wood and plastic, no need to sweat the
small stuff.

Try it for a short length first, it takes a while to f6.

On 21/07/2022 23:37, Bogdan Caramalac via Discuss wrote:

To unsubscribe send an email to discuss-leave@lists.openscad.org