The That?s a good idea. I?ll see if I can determine if the hole is actually a tad undersized by seeing if a 1/8 in bit will fit through it. If it won?t, I?ll try a 7/64. I suspect I?ll end up getting a 3/16. I will probably end up getting the MS24665-289. But I wish a few more people would respond and tell me PRECISELY what they used. I think I?ll call MATCO tomorrow since the axle and associated parts are their products. I?m sure they can tell me. As I was researching this, I did run across another part number for this cotter pin on the MATCO site: MSC.125X2COTTERPIN. Someone said that the ?.125? indicated 1/8, but it is actually a shade smaller. It was mentioned that this the pin MATCO actually supplies with the axle. I just wasn?t sure that this particular MATCO axle was the RV12 axle.