Hi-Lok$^{®}$. An interference fit is typically used for aluminum  and a clearance fit is used for steel, titanium, and composite  materials.  [Figure 4-107]  After installation, a lockbolt needs to be inspected to  determine if installation is satisfactory.  [Figure 4-108] Inspect the lockbolt as follows: Bolts are threaded fasteners that support loads through pre- drilled holes. Hex, close-tolerance, and internal wrenching  bolts are used in aircraft structural applications. Blind bolts  have a higher strength than blind rivets and are used for  joints that require high strength. Sometimes, these bolts can  be direct replacements for the Hi-Lok$^{®}$ and lockbolt. Many  of the new generation blind bolts are made from titanium  The best way to remove a lockbolt is to remove the collar and  drive out the pin. The collar can be removed with a special  collar cutter attached to a drill motor that mills off the collar  without damaging the skin. If this is not possible, a collar  splitter or small chisel can be used. Use a backup block on  the opposite side to prevent elongation of the hole. The Eddie-Bolt$^{®}$ 2 looks similar to the Hi-Lok$^{®}$, but has five  flutes, equally spaced along a portion of the pin thread area.  A companion threaded collar deforms into the flutes at a  predetermined torque and locks the collar in place. The collar  can be unscrewed using special tooling. This fastening system  can be used in either clearance or interference-fit holes. Figure 4-107.  Lockbolt installation procedure. Figure 4-108.  Lockbolt inspection. Lockbolt Inspection Blind Bolts The Eddie-Bolt$^{®}$ 2 Pin Fastening System  1.  The head must be firmly seated. 2.  The collar must be tight against the material and have  the proper shape and size. 3.  Pin protrusion must be within limits. Lockbolt Removal 5/32 3/16 1/4 5/16 3/8 Nominal Fastener Diameter Y Z (Ref.) R Max. T Min. .324/.161 .280/.208 .374/.295 .492/.404 .604/.507 .136 .164 .224 .268 .039 .253 .303 .400 .473 .576 .037 .039 .037 .110 .120 Lockbolt/Collar Acceptance Criteria R Z T Y 1 2 3 4 Continued force breaks the  pin and ejects the tail. Anvil  returns and disengages from  the swaged collar. The initial pull draws the work  up tight and pulls that portion of the shank under the head  into the hole. Further pull swages the collar  into the locking grooves to  form a permanent lock. Placed the pin in the hole  from the back side of the  work and slip the collar on.  The hold-off head must be  toward the gun. This allows  the gun to preload the pin  before swaging. Then apply  the gun; the chuck jaws  engage the pull grooves of  the projecting pintail. Hold  the gun loosely and pull the  trigger. 4-53