On collet-equipped jacks, during rising, how far should the collet be kept from the lift tube cylinder?

On collet-equipped jacks, during rising, how far should the collet be kept from the lift tube cylinder?

• A. Two threads from the lift tube cylinder
• B. Four threads from the lift tube cylinder
• C. Flush with the cylinder
• D. Beyond one thread from the cylinder

Answer: (A)

The collet should be kept a small clearance from the lift tube cylinder during rising—specifically about two threads worth of distance. This gives a safety margin so the collet doesn’t contact or bind on the cylinder’s threaded area as the jack extends, protecting the threads from wear or damage and ensuring smooth, reliable operation. If it’s too close (flush or within one thread), the moving parts can rub or bind, leading to wear or binding under load. If it’s set farther away (for example, four threads), you risk reduced engagement accuracy and potential instability in the load path. Two threads provides the proper balance of clearance and engagement for safe operation.

The collet should be kept a small clearance from the lift tube cylinder during rising—specifically about two threads worth of distance. This gives a safety margin so the collet doesn’t contact or bind on the cylinder’s threaded area as the jack extends, protecting the threads from wear or damage and ensuring smooth, reliable operation. If it’s too close (flush or within one thread), the moving parts can rub or bind, leading to wear or binding under load. If it’s set farther away (for example, four threads), you risk reduced engagement accuracy and potential instability in the load path. Two threads provides the proper balance of clearance and engagement for safe operation.