Putting a new chain on the 640, and the peen-type master link won't go through the open hole on the chain at all. So, I figure I'll give the clip-type master link a shot. Same thing. Neither is willing to make this journey on to my chain. I tried getting my chain tool in place to press it through, but there is not enough space to make this work on just one plate of the master link. I'm concerned that if I try setting it up where I squeeze both plates, I'll bend the one that is not the one I'm trying to feed the master link through. So, I'm not doing that. So, maybe a gentle buzz on the first hole with the dremel? The master link goes right through the inner link hole. No problem there. Anyone else experienced this? S.C.