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Bent Brovold Lift Screw?

Did you bend the lift screw on your AFGB1?  Take heart.  You’re not alone.

A Common Problem on AFGB1’s:  Bent Lift Screws

The Pine AFGB1 is designed with a screw system to lift the gyratory head off the compaction chamber and rotate it out of the way.  Unfortunately, the lift screw that forms the cornerstone of this system frequently requires replacement because it got bent.  Bent lift screws 100% preventable. 

 Figure 1:  The AFGB1 Gyratory.

How Lift Screws Get Bent

There are only two appropriate positions in which to leave the gyratory head—“up and away” or “down and clamped (Figure 2).  The problem occurs when the gyratory head is “up” but not “away” or “down” but not “clamped” and the ram is run up.  As the ram moves upward, load is applied to the bottom of the gyratory head, which is only supported by the lift screw when the head is not clamped to the compaction chamber.  This leads to a bent lift screw, which must be replaced.  

Figure 2:  Acceptable Gyratory Head Positions.

Fixing a Bent Lift Screw

Acquire and install a new Lift Screw Kit, which includes a lift screw and the associated hardware. (Pine Part Number ACGBG18K).

What does Pine Recommend?

Only leave the gyratory head in the “Up and Away” or “Down and Clamped” positions.

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