Tripod Head Bolt

Tripod Head Bolt

Sooner or later you will find something that you want to attach to something else, and if any of those some-things is a camera or a tripod, you will soon meet the challenge of WTF? its almost an M6? what the hell is it?

Say hello to the 1/4-20 UNC, a cunning little bolt that in the UK takes a little bit of hunting!

Per ISO 1222:2010, the current tripod screw thread standard for attaching the camera calls for a 1/4-20 UNC or 3/8-16 UNC thread. Most cameras people will come across are fitted with 1/4-20 UNC threads. Larger, professional cameras and lenses may be fitted with 3/8-16 UNC threads.

Historically, the thread standard for attaching older cameras to tripods was 1/4-20 BSW for smaller cameras or 3/8-16 BSW for larger cameras and pan/tilt heads. In this application the BSW and UNC thread profiles are similar enough that one can mount a modern camera on a legacy tripod and vice versa. The UNC threads are 60 degree angle and flattened, whereas the BSW are 55 degree angle and rounded crest.

I have assembled the following OpenSCAD code to give me the right size Threaded Rod, Nut Trap, Bolt, and head clearance holes.

/*
	Threaded rod for camera mounts, Clearance Holes, and Nuts for NutTraps.

	1/4" - 20 Unified National Coarse, British Standard Witworth.
	This thread is used for rangefinder camera, roll film cameras (also DSLRs) up to medium format cameras, quick release plates and panoramic heads.

	3/8" - 16 Unified National Coarse, British Standard Witworth.
	Some medium format cameras and almost all large size cameras as well as most of the connectors between tripods and panoramic heads use this thread.

	This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/4.0/.

*/

// Variables for 1/4" 
RodDia = 6.35; 			// Diameter of the Bolt
NutH = 4.4;				// 11/64" = 4.365625 mm
NutDia = 12.84;			//  7/16" across flats

/*
// Variables for 3/8" 
RodDia = 9.53; 			// Diameter of the Bolt
NutH = 6.35;			//  1/4" = 6.35 mm
NutDia = 16.5;			// 9/16" across flats
*/

module CameraNut()
{
	// Use for nut trap
	cylinder(d = NutDia, h = NutH, $fn = 6);
}

module BlankCameraHole()
{
	// Round hole 1mm bigger than accross corners.
	cylinder(d = NutDia + 1, h = NutH);
}

module CameraRod(Length = 24.5)
{
	// Blank Rod
	cylinder(d = RodDia, h = Length);
}

module CameraBolt(Length)
{
	// Assembled Bolt
	translate([0,0,-NutH])
	{
		CameraNut();
		CameraRod(RodDia, Length);
	}
}

CameraRod(24.5);

I will be using it in projects in the future.