necessarily remove aluminum chips - with tinkering also suitable for walimex

I was looking for an inexpensive, lightweight and travel-performance alternative to a nodal point for panoramic photography and what can I say - it works well - and indeed in the following combination:
I use a ball head and a SIRUI Nikon D90 with a walimex / Samyang 8mm fisheye, for which there really no tripod collar is. I have here the (very thin) velvet upholstery removed therefrom and replaced by about 1 mm thick rubber (the mounting of a bicycle light). thus fits perfectly the clamp vertically or diagonally to the objective and the structure in the nodal point to the tripod. However, the hidden aperture ring - that makes my case but nothing that I Obektiv eh permanently place the panel at 8.

quality: pretty solidly built in part, for the price certainly reasonable quality. However, one should note the following: For me both were threaded added with a mixture of fat and aluminum chips. I had to remove troublesome times with cotton swabs and isopropyl and lubricate again. otherwise everyone will screwing the violence. therefore 1 point deduction.