The best I can do for you is Bossard. They have a M4 X .5 lock nut(polyamid insert), but only in A2 stainless.<br>Bossard California(562) 926-0318 <p>Edson Campos<br><a href=mailto:edsoncampos@earthlink.net>edsoncampos@earthlink.net</a><br><a href= > </a><br>