I have an atlas 7b. Just got it. Nice shape. When the ram gets to about 3/4 of forward stroke I feel a definite CLUNK and it leaves a line all across the work. Otherwise it works fine. I suspect it is from the ram drive mechanism. Do any of you guys recognize what this might be? I will go in and tear it down, looking for something loose but if anyone can tell me off the bat that they know what it could be that might help. Thanks.