The problem with worm drive clamps is not with the clamp, it is that they can be over-tightened and then they cut through the rubber line. This used to be a common problem when in-line fuel filters were used on the rubber line between the fuel pump and the carburetor. The fuel filter would get changed every time a tune-up was done and the clamp would get tightened and cut deeper into the rubber line eventually causing a failure/leak.

The clamp manufacturer's provide tightening specs for their clamps but they are not commonly referred to.

Let me know if you need additional information and I will see if I can find anything in my old trade school books.

Scott D. Melville
IAAI-CFI®, IAAI-ECT, CFEI, CVFI, CCFI-C
Victoria, British Columbia
www.triplesevensfire.com