The cameras are fixed with a tripod socket screw. The screws on the market doen't always fit dimensionnally the kaper's needs.
This screw has a special thread as an american standard, and is not always easy to find elsewhere. The definition is:
1/4", step 20, thread type UNC or Withworth
which is: diameter = 1/4 inch, or 6,35mm
with 20 threads per inch.
It is usually named 1/4-20NC
In special shops, it is possible to get such nuts and bolts. Some agricultural equipment retailers may have it as well..
Taps and dies are also available, usually as ordered, but price is usually rather high because of professional equipment, 40 to 50 euros. In the United States, it would be only $4  to $6 each!