Engineer minds please help

[LRshooter6mm]

I’m trying to design and 3D print a part for a picatinny rail clamp that acts like the Really Right Stuff VYCE where both clamp walls move in or out from turning the knob. I’ve been looking at different version and some utilize an inner and outer threaded bolt and I just cant wrap my head around how it works or where to find the parts. Any assistance would be appreciated

 

[LeftyJason]

Closest thing that I can think of would be like a turnbuckle style connecting rods. One end is standard thread and opposite end is left hand thread.

McMaster Carr has some both internal and external thread. "turnbuckle style connecting rods"

"Left hand stud" search might help as well.

 

[LRshooter6mm]

Thanks, I’ll see what I can find in that regards

 

[AllenOne1]

A self centering drill guide works on the same principle using RH and LH threads to keep the sides equal distances from the center of the jig. The center portion is pinned to the screw shaft to hold it solid while still allowing the screw to turn. I have no idea where you would find parts like that in a size that would work for your purposes.

 

[LRshooter6mm]

I found some double threaded lh and rh stud and some lh nut. I’ll give it a try. How is the center portion pinned to the screw shaft?

 

[AllenOne1]

I found some double threaded lh and rh stud and some lh nut. I’ll give it a try. How is the center portion pinned to the screw shaft?

I think the center of the screw has a flat groove machined in it and a pin screwed in from the top rides in that groove to keep it centered. Never really had it that far apart though.

 

[Terry Cross]

McMaster Carr has a wide selection of fasteners and components ALONG WITH DOWNLOADABLE CAD FILE for each. Very handy.

 

[RubiconJoey]

The same effect can be achieved with a rack and pinion setup. Many phone holders have this kind of mechanism. There are two racks, each connected to one side of the clamp. The racks are driven by opposite sides of the pinion gear which either pulls them in or pushes them apart.