The most Common Side Rails used on our Williams widebody Virtual Pinball Cabinet are the original Williams stainless steel side rails, Part number A-12359-3. These can be found at either Pinball Life or Marco Pinball. It is important to remember that when installing these, do so while your Backbox is removed.
So let's get started.
First lets remove our backbox and line the side rail up so that the front edge of the side rail is flush with the front edge of our cabinet
After that make sure the rear piece of the side rail is flush with the rear of the main cabinet playfield like below.
Many people like to use double-sided tape on the underside of the side rail to help keep it in place. If you would like to do this, be sure to review the MJR Networks section on installing side rails.
http://mjrnet.org/pinscape/BuildGuideV2/BuildGuide.php?sid=cabHardware
In my experience, you only need a small amount of the tape.
After the side rails are installed and you are happy with the alignment, go ahead and attach them in the front using an 8-32 x 1-1/4" Side Rail Carriage Bolt Part Number 4308-01123-18 and 8-32 Black Nylon Insert Lock Nuts Part Number 240-5102-00B. These items are included with our assembly kits. For the rear section, any standard-style wood screw will work. In addition.
Awesome, you are now done and ready reinstall your Backbox!!!!