One of the tips I came up with some time back was creating a small lip or hook in the dryer’s exhaust pipe and the rigid pipe coming through the wall. This is accomplished with a pliers or vise-grip and done in two areas of the circumference. Once you tighten your worm drive clamp down, we’ve found it is pretty dang secure. Look at the picture for a close-up of the small hook feature.
Be careful not to grab to much material as it will interfere with sliding your flex pipe onto the collar. Try to only grab just enough to get a firm bite.
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Hope this helps. Good luck.