DEC Axis Dis-Assembly


Start with all bearings cleaned and re packed with grease.

Have some shim stock available, try Enco for this.

You might want to remove the brushed paint with a razor blade and some denatured alcohol.  The purpose of this paint is to hide the raw aluminum of the castings when they misalign due to adjustments for the worm mesh.

The upper DEC shaft bearing is installed into the housing.  You may need to tap lightly around the perimeter of the outer bearing race to install it.  Alternate sides every tap!  I suggest using a plastic or leather hammer for most of the installation.  Switch to a small (3/16" diameter) flat faced punch and regular (small) hammer to do the final seating.  The clunk noise will change to a very solid sounding higher pitched clank when the bearing seats.  A light film of oil or grease on the outside of the bearing will make it slide in easier without tearing metal away from the casting.  Ask any auto mechanic friend for help.....



Place the plastic shim washer (barely seen in the bottom of the DEC shaft head casting) over the shaft and then install the worm wheel and bearing assembly.  Do not install the worm housing casting at this time!



Insert the shaft and gear assembly into the DEC housing.  Do Not install the plastic spacer that was in between the Upper DEC shaft Bearing and the lower Worm Wheel bearing.  You will need to measure the distance from the face of the casting to the upper face of the worm wheel.  Data Item A



Measure the thickness of the worm wheel, this will be Data Item B



You will then need to make this measurement.  It will be Data Item E



Here's how I did it.  First measure the distance from the face of the casting to the inside face of the bearing bore.  This will be Data Item C



Then measure the diameter of the Worm Shaft, it will be Data Item D


Data Item # Description Measurement
A Casting face to upper Worm Wheel  face 0.775"  
B Thickness of Worm Wheel 0.476
C Worm bearing inner face to casting face 0.390"
D Diameter of worm shaft 0.313"
E Center of worm shaft to casting face 0.547"
F Center of worm wheel to casting face 0.537"

You now have everything you need to calculate the shim needed for correct worm to worm wheel placement.

The distance from the face of the DEC casting to the center of the worm wheel gear = A - (B/2) or in this example 0.537"

The distance from the center of the worm shaft to the face of the worm shaft casting = C + (d/2) or in this example 0.547"

The shim needed = E - F or in this example 0.010"


Copyright 1997-2012 by Bill VanOrden