Alstar M48X0.75 Male/M42X1 Female to M42X0.75 Male Telescope Adapter

I got this to adapt my M42 thread camera to my M48 thread Starzonia filter box. It worked as far as getting the devices mated, but the male threads were a problem. Most of my 2″ filters are mounted in rings that are quite thin front-to-back. They have just enough thickness to allow them to be threaded. The adapter worked just fine with them. However, I have 2 filters – a moon filter and a cross-field filter – that have a much thicker ring. The male threads on the adapter entered the filter box far enough as to block the thicker filters from being used. Had the company included a lock ring on the male threads of this filter then I could have backed it out far enough for the two thick filters to enter the box and locked to tightly together with the lock ring. But, there was no lock ring, so I purchased a different style adapter to do the job.