I was asked to make a new nosepiece for a Hartnack microscope which would enable the owner to use RMS objectives as he finds Hartnack objectives very fiddly. The Hartnack has a small diameter male Thury thread whereas the RMS is a larger female Whitworth thread. The nosepiece maintains the tube length but the Harnack has an adjustable tube length anyway and the new nose piece works just fine. As you can see there is quite a difference in the width where the objective attaches. The new RMS nosepiece looks a little clumsy compared to the original.