I recently added the CRC delrin steering blocks with axles to my car. Its got axles which are secured with an e-clip on the inside. I can't find anything like them on the crc site. The question is, what size are the nuts to secure the wheel? It's roughly the size of a 4-40 but with finer pitch. Is it metric? I lost a wheel in my last main because the nylon in the nuts that came with them is worn out. I need some new ones!