From IAP-Wiki

Contents 1 General Information 2 Alternative Names 3 Bushing Sizes 4 Tube Length(s)and Diameters 5 Drill Size 6 Sources 7 Assembly tips 8 Other Guidelines

General Information

Penn State Industries (PSI) also has an Apollo Elite.  The two pens are not identical.

Alternative Names

Bushing Sizes

The measured fitting sizes are

.563    Nib

.534    Lower tube on center band end

.647    Cap Center band end

.6235   Cap clip end

Tube Length(s)and Diameters

2.129    Nib Length

 .480    Nib Outside Diameter

1.697    Cap Length

 .548    Cap Outside Diameter

Drill Size

Sources

Penn State Industries

Assembly tips

Use a pair of needle nose pliers or standard slip grip pliers to press the clip ring carefully into the grove in the "Dome Disk".  If you do not do this,  you will see a gap around the "Cap Dome".  Be careful not to scratch the visible outside surface of the "Dome Disk". You may need to carefully file the outside of the clip ring so it will fit into the dome disk.

Other Guidelines

Link to Instructions on Penn State web site (External Link)