The ArcEurotrade guide covers the X3.
http://www.arceurotrade.co.uk/projects/prepguides/X3%20Mill%20Preparation%20Guide.pdf

Most of the same procedures apply to the SX3 also. I will focus on the differences.

http://www.grizzly.com/products/G0619/parts/1

The ArcEuro guide removes the table first. I will want you to remove the head first, because it is easier to do with the table still functional.


So here is the new mill, bolted down to its pallet, totally unsuspecting of the havoc about to be wreaked:
 

We'll start by removing the four screws from the electronics cover and then
the cover itself. We'll be leaving the motor wire cables attached. Be careful
not to bend or break them. We will remove the cover and head as a unit.
 

When everything is apart, All of this red wax will have to go:
 

If you are going to keep the quill DRO and Quill, then you don't HAVE to remove
them. The DRO has been known to cause shorts and burn up the motor control
board, so I prefer to remove it. It won't be needed for CNC. I also prefer to
remove the quill drive, as I will not use it for CNC, and without it the head will be
lighter and cleaner. Make sure now that the quill lock lever at lower right is locked.


Unscrew and remove the spindle safety cover:
 

Take the screws from the tachometer, unplug the wiring and remove it:
 

Remove those 4 long screws and the top of the head. You may notice that I am replacing screws where
they go, whenever possible to keep track of them.
 
You could now remove the motor if you wished, by just removing the four motor/plate screws, the belt, and
then removing the 4 motor screws from underneath. You would first have had to unfasten all of the motor wiring from the other side of the motor cable housings. None of this is necessary for just cleaning.

http://www.grizzly.com/products/G0619/parts/1

See that big round cap? Use a pair of channel locks to wiggle it loose. remove the torsion spring underneath, the support flange and the soft metal holding ring and that keeps the quill drive in place. Make sure the quill is locked. Now remove all of the quill drive mount screws from the other side and slide the entire quill drive assemble out of the head.
 

Voila! You have just removed 12 pounds of cast iron that your Z stepper will now not have to lift.
 

I chose to remove the usless and PITA chuck guard. I just pulled the wires off the switch, taped them
individually so they didn't touch each other, and pushed them back into the head. Later, I used those
wires, which run all the way back through the big cable housing to the electronics bay, to control spindle
motor start/stop.


It's time to remove the head. Crank the Y axis back as far as it goes. Crank the head down until the spindle rests on a block. Also block up the head so it can balance on the table when removed. Now see that big nut at center right below? Remove 
that and the one on the other side. Have somebody help you balance the head and crank the y axis forward to remove head.
To reinstall, just do this in reverse, guiding the two head bolts back into place. 
 
Put the head into a box, and move both head and attached electronics box to a safe, out-of-the-way
location.

You can now remove and set aside the friction disk. Careful! there are six small compression springs
inside. Just gently twist and pull the big white disk:
 

 
OR, you could just leave it IN there.

Now remove the head bolts and set them aside together with nuts and washers:
 

Next you will want to crank the head saddle up to its highest point and support it with a block:
 

Now remove the gib screws from top and bottom:




Gently pry ip the gib:
 

and remove it:
 


There are several screws front and rear that hold the sideplates on. Notice that the LONG side goes UP:
 

Remove all the screws and remove the sideplates:
 

http://www.grizzly.com/products/G0619/parts/0

The Z bearing block screws are very hard to loosen. Here's one way to make it easier:
 

After loosening the screws, remove them.
 

Gently pry out the bottom bearing block:


 

And gently wiggle loose the top bearing mount. Now remove entire shaft and lay aside:
 
At this time, follow the ArcEurotrade guide to remove the table and saddle.

http://www.arceurotrade.co.uk/projects/prepguides/X3%20Mill%20Preparation%20Guide.pdf

Then you are ready to remove the column, If you want to. If all you are doing is cleaning, you can probably
leave it on. You MUST remove the column to install the CNCFusion kit however.

Remove the column bolts. The column will still be held tightly by taper pins after you do this.
 

So it becomes a gentle prying exercise to remove it:


 
Now that the column is loose. If you EVER plan to increase Y travel as I did, NOW is the time to drill
and machine the bottom. If you ever plan to increase the Z travel as I did, now is the time to drill the top.

One last thing to do. Loosen the set screw from the Z handle shaft, and pry the gear from the shaft:


Now remove these three screws from the Z handle support flange and pull the entire shaft out the front:
 

That's it. Now you can clean and smooth the ways as illustrated for the X2 Teardown:

http://crevicereamer.com/Page_9.html

CR.