I wonder if someone can help me find the correct size replacement bolt/screws. I am using my Allen keys to try to find the correct size bolts but the conversion charts are either contradictory or at least confusing. I wonder if someone can point me to a chart or give me the right sizes. Bolt one is a socket head and the Allen key that fits is a 2.5 mm. Bolt two is countersunk and a 2 mm key fits. I get them both to be M3. It is confusing that the M size changes with the head type. Am I correct? Thanks in advance. Andy.