16 CHAPTER ONE Magnetic Stand A magnetic stand (F tgu re af) is used to hold a dial indi- cator securely when checking the runout of a round object or when checking the end play of a shaft. V-bloc ks V-blocks (Fi g ure 42) are precision-ground blocks used to hold a round object when checking its runout or condi- tion. Surface Plate A surface plate can be used to check the flatness of parts or to prov ide a perfectly flat surface for minor resurfacing of cylinder head or other critical gasket surfaces. While industrial quality surface plates are quite expensive, the home mec hanic can improvise. A thick metal plate can be used as a surface plate.
The surface plate s how n in Figure 43 has a piece of sandpaper glued to its surface that is used for cleaning and smoothing machined surfaces, such as the cylinder head. NOTE A local machine shop can fabricate a sur- face plate. 1\1ECHANIC'S TIPS Removing Fr ozen Nuts and Screws Expendable Supplies When a fastener rusts and cannot be removed, several methods may be used to loosen it. First, apply penetrating oil such as Liquid Wrench or WD-40. Apply it liberally and let it penetrate for 10-15 minutes. Rap .thc fastener several times with a small hammer; do not hit it hard enough to cause damage. Reapply the penetrating oil if necessary. Certain expendable supplies are also required.
These include grease, oil, gasket cement, shop rags and cleaning solvent. Ask the dealer for the special locking com- pounds, silicone lubricants and lubricants that make vehi- cle maintenance simpler and easier. WARNING Having a stack of clean shop rags on hand is important when performing engine work. However; to prevent the possibility of fire, store solvent-soaked rags in a sealed metal container until they can be washed or dis- carded. For frozen screws, apply penetrating oil as described, then insert a screwdriver in the slot and rap the top of the screwdriver with a hammer. This loosens the rust so the screw can be removed in the normal way.
If the screw head is too damaged to use this method, grip the head with locking pliers and twist the screw out. Avoid applying heat unless specifically instructed, as it may melt, warp or remove the temper from parts. NOT E To avoid absorbing solvent and other chem- icals into the skin while cleaning parts, wear a pair of petroleum-resistant rubber gloves. These can he purchased through in- dustrial supply houses or well-equipped hardware stores. Removing Br oke n Screws or Bolts lf thc head breaks off a screw or bolt, several methods arc available for removing the remaining portion.