KnuckleHead Extensions should be used with our product to elevate equipment and pipes above the adjustable height range of a base model KnuckleHead.  Green Link provides extensions of 8, 12, and 18 inches. If you want to make your own size extension the following are the steps to make a custom extension.

Step 1

Add a 3/8”x16  1-1/8” Hex Rod Coupling Nut Zinc Plated use thread locker screw half way onto base threaded rod as shown.

KnuckleHead Base with Loctite

Step 2

Next determine the size of the extension you are wanting to make.  In this case we are making a 12” extension.

Cut 3/8”-16 threaded rod 2 ½” shorter than desired extension length – for 12” you will cut threaded rod at 9 ½”.  Install threaded rod with thread locker placed on bottom to the Hex rod coupling nut securely tighten.


KnuckleHead base with threaded rod and coupling extension

Step 3

Cut 2 ½” Electrical Grade Schedule 40 PVC for the extension.  You will cut this piece ½” shorter than the desired height of the extension.  For the 12” Extension cut PVC to 11 1/2” and slip PVC extension onto Universal Base as shown.


knucklehead with extension pvc custom size

Step 4

Place the desired KnuckleHead top on the extension by screwing top onto threaded rod until it is firmly in place.


KnuckleHead custom extension how to


You have now completed the 4 steps to make an extension.

*If you are extending over 18” in height you will need our custom large base.