We collected an old glass tv cabinet that we want to use for photographing guinea pigs on due to it being glass and providing better all round lighting but its too big. It's made of three glass shelves held together with cylinders that have lone thread bars going through them. The bars are only threaded about an inch and a half on each end and I want to do away with two of the shelves thus I need a shorter length of bar. I have a digital Vernier and have measured the bar at 7mm, the thread diameter is 7.66mmand the internal measurement of the threads is about .74mm. From what I have googled this looks to be between M6 and M8 so is it more likely to be imperial?