Originally Posted by SteveI
1) It is not a problem with all frames and low end stringing machines.
2) It is a problem when you string certain frames with low end stringing machines. These low end stringing machines have too much flex or play in mounting supports or base. Or a both could be an issue.
3) This not a function of 2 point vs 6 point mounting systems. There are many fine machines that employ 2 point and 6 point systems.
4) When you combine certain frames and certain low end machines (Sorry Klippermatre Users), you see head compression.
5) The frame I have seen this occur with are many of the Head Twin Tube models.. ie Radicals, Dunlop MW series. Some of Volkl line. You will not see head compession on a Wilson PS 6.1 and a POG.
6) Incorrect Mounting (User Error) on a good machine can also produce head compression with these certain frames
I'm sorry to beat a dead horse but there is no flex in the mounting system on my Klippermate. Granted, mine's 20 years old and they might have changed it a bit. But the mounting posts on mine are half inch X 2 inch solid steel. You could pull 500 pounds of pressure on these and they're going nowhere. The most common racquets I string are Volkl V1 Classics and Dunlop Aerogels. Also, lots of Prince with O holes. Don't have a problem.
I still contend that poor mounting is the culprit in most of the cases. String tension differential could play a role also. I almost never string more than 2 pounds difference.