Hi Slingerfan!I just looked through quite a few Rogers catalogs and each one refers to this part as the "collet nose". I was hoping to find one that showed it as a "nut" but came up empty.First two pictures are from the 1964 catalog. The third picture is from the 1970 Accessories catalog, which also gave this a new part number!-Mark

You are correct Mark, Rodgers does call it the "collet nose". Industry standard is "collet nut" which seems to be more descriptive and less ambiguous, especially for those who understand fasteners like yourself. Both the collet and collet nut could be said to have a 'nose'. While attempting to make things more clear, I'm afraid I've just muddied the waters (LOL).

i have found that the “fingers” can wear a bit over time and don’t provide a good clamping action onto the hex rod or spur. i have been successful with using a rubber headed mallet to gently hammer the fingers together towards each other a little bit. then when tightening the collet nut, more force is applied. it has to be done gently so as not to snap off the fingers. it seemed to work well for me when i had the exact problem you desctibe. i also recommend the machined collets. dave drew makes them. he is located in woonsockett rhode island.