I have included the Inventor plans that are the example I will show my students, I know there are missing dimensions (what can I say, I like to keep my students on their toes). You could just as easily work from your goose neck and measure as you go.
I begin by sketching a 45mm square, then pull it up 20mm. This will create basic shape for the bar clamp.
Now I will add the three fingers for the Go-Pro mount. These will be 3mm thick and 40mm high.
Step 1: Bar Clamp Basic Shape
I will create the basic shape using rectangular prisms, bar clamp (45 x 45 x 20mm) and locate the clamp bolt holes. These are 11mm from the outer edge and are 6mm diameter.
Step 2: Sketching the Go-Pro Mount Fingers
I now need to sketch three 3mm wide fingers with a 3mm space between them. First I sketched the centre finger then added two more on either side. I will pull up the centre and outer sections 40mm high to create the basic shape for the mount. The mount has a 5mm hole through all three fingers, centred on the width and 10mm down from the top. After sketching this I push the circle 20mm to ensure it goes through all three fingers.
I will also need to create the bar clamp bolt head recesses, by sketching and pushing an 11mm hole 10mm down.
Step 3: Shaping the Fingers and Body
I now sketch the shape for the fingers by drawing a 20mm circle, centred on the hole, and join the centre point to the base with lines. These are trimmed to remove un wanted line segments. the outer edges are pushed 20mm to edit all three fingers. I will also add the fastening bolt nut recess to one of the outer fingers. this is simply achived by pulling 5mm the area between a circle and hexagon.
The top arcs of the bar clamp are sketched to match the original bar clamp using a 3 point arc. I select the two side midpoints then drag up to the top midpoint. This is pushed 15mm back to the Go-Pro mount fingers, I simply measured the distance.
Next I draw a line from the midpoint on the base 11mm down, this is the mid point for the lower clamp arc. I draw a 22mm diameter circle from this, removing unwanted sections, pushing this to the other side.
Step 4: Nuts and Bolts
Now to try something a bit tricky...
if you can imagine what the bolt holder looks like in a sectional view, you can draw it and revolve the shape around a centre line. To do this you will select a plain on which to sketch, I chose the vertical so it loads to the 3D printer easily. First I draw a rectangle, 10mm wide x 8mm high followed by a 3mm wide x 42mm high rectangle joined to the first rectangle. I trim away unwanted line sections and select the revolve tool. First select the face to be manipulated then the axis. Now i sketch a circle and a hexagon onto the inside of the bolt holder, pusing the hole 8mm and the outside of the hexagon 5mm.
Step 5: Fillets and Bevels
I can now tidy up any edges using the fillet and bevel tools. I chose a 1mm fillet around the edges, as some parts have only a 3mm thickness, and kept it fairly uniform.
Step 6: Export and Print
I will export my individual components by opening the bodies menu, select and right click on each item and save them as an STL to my computer and connect to my printer, it's only a cheap one but occasionally it works, lol:)))