Metal M42 42mm 1mm Thread Pitch to T2 42mm 0.75mm Male to Female 42mm to 42mm Coupling Ring Adapter for Lens Filter

Perfect conversion allowed me to use a Vivitar 3x teleconverter for M42x1.0 lenses on my T2 (M42x0.75) telescope.

I needed an adapter to convert T or T2 (42mm x 0.75 mm) to M42 (42mm x 1.00mm). The adaptors female threads (T) are sufficiently deep allowing for a full three turn thread engagement. The male threads (M42) are too short and only allow for ONE full turn of engagement. This short thread prevents the lens adjustment controls to be on the bottom side of the lens. This short thread engagement also puts excessive strain on the threads which connect the camera to the lens and possible damage to the cameras M42 female threads.

Works Well, Nicely and Precisely Machined

Perfect

Fits great! Now I can attach my Telescope extension tube to take photos of the night sky!

There are two incompatible M42 threads in use: one used primary on telescopes (42mm x 0.75mm) and another primary used on cameras (42mmx 1.0mm). This ring has Male camera (1mm thread pitch) threads and Female telescope (0.75mm thread pitch) threads. The compliment to this ring is:https://www.amazon.com/gp/product/B07QFS4WW9I used this particular ring to convert weird Spiratone T2 threaded bellows lens to a useable 42 camera thread. I also epoxied one to the top of a 45 degree 1-1/4 telescope erecting prism so that I could attach a camera.