Abstract:
A handheld precision clamping apparatus for sanding acoustic guitar saddles comprised of a generally rectangular base with a clamping mechanism, comprised of a clamping bar located in the base&#39;s lowest extremities, so that the low profile nature of an acoustic guitar saddle can be effectively grasped perpendicular to a separate flat sanding surface, the material to be removed from the saddle extending beyond the flat-bottom surface of the apparatus, ensuring precise material removal.

Description:
BACKGROUND OF INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a system for precise sanding and more particularly to a precise sanding method for use on acoustic guitar saddles by individuals or guitar luthiers. 
         [0003]    2. Description of the Related Art 
         [0004]    Acoustic guitars are very popular with many musicians and individuals playing in bands, solo engagements or just for fun. In some applications, a guitar saddle must be sanded down to interface with an under-saddle pickup or to lower the strings&#39; action for easy playing of the instrument or for changing out an existing saddle for a better material such as bone, tusk, etc. It is very important that the bottom surface of the guitar saddle is perpendicular to its sides and perfectly flat, which is critical to proper pick up function and sound. The applicant realized the need to accomplish this in a precise way. 
         [0005]    The applicant looked for such an apparatus that would fulfill his needs. After searching the internet and trade magazines for luthier tools, no adequate apparatus was available. The most common method for removing material from the saddle is to make a pencil mark or scribe line on the saddle and remove material using a belt sander, disk sander, vise and file, or while holding the saddle in your hand moving it back and forth on a piece of sandpaper taped down to a flat surface while trying to keep the sides of the saddle at 90 degrees and maintaining equal pressure on both ends of the saddle. Ensuring accurate positioning of the saddle while sanding is very difficult, and the results only approximate. A milling machine would be very accurate, but job setup would take some time, and a milling machine can be very expensive while offering little other use to guitar makers. As a result, the applicant invented this precision clamping apparatus. 
         [0006]    This invention will make precision guitar saddle work easy and efficient, in addition to providing a clamping method for holding the saddle secure while sanding to a precise amount. This method, which uses feeler gauges, makes this a very precision tool for saddle work. 
         [0007]    For example, aftermarket electrical sound pickups are installed under the existing saddle and rest on the guitar body where the saddle was originally. Because the pickup has a finite thickness, in some cases 0.053″, one would need to remove 0.053″ from the bottom of the saddle to maintain the guitar&#39;s playing characteristics, or action. Using the aforementioned methods is a very time consuming task, and, with the exception of using a milling machine, holding these tolerances is near impossible. The risk of removing too little or too much material from the saddle is very probable, and the end result is having to start over with a new saddle, creating additional costs and loss of time for the individual or repair shop. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    In one embodiment of the present invention, the precision clamping apparatus, employing a clamping bar for holding the saddle in place during sanding, includes an aluminum base with an L-shaped slot for both accepting the saddle and holding the clamping bar; a clamping bar held in place by a roll pin on either end; two clamping bar screws to hold the saddle during sanding; a set of replaceable stainless steel shoes which simultaneously provide superior durability as a sanding surface and also secure the clamping bar in its slot; and a push pin for seating the saddle to an underlying flat surface. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    So that the manner in which the above recited features, advantages, and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings only illustrate preferred embodiments of this invention, and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments that vary only in detail. In the drawings: 
           [0010]      FIG. 1  is a front side perspective view of a preferred embodiment of the precision clamping apparatus, showing the base and its components. 
           [0011]      FIG. 2  is an exploded view of the precision clamping apparatus shown in  FIG. 1 , showing all components. 
           [0012]      FIG. 3  is a right side perspective view of the precision clamping apparatus shown in  FIG. 1 , showing the bottom shoes with the clamping bar in the open position and push pin in its storage position. 
           [0013]      FIG. 4  is a right side perspective view of the precision clamping apparatus shown in  FIG. 1 , showing the bottom shoes with the clamping bar in the closed position and with a guitar saddle clamped in place. 
           [0014]      FIG. 5  is a bottom perspective view of the precision clamping apparatus shown in  FIG. 1 , showing a protective plate for rough sanding with an electric rotary tool using sanding drum attachment, before the final precision sanding procedure previously described. 
           [0015]      FIG. 6  is a left-side perspective view of the precision clamping apparatus shown in  FIG. 1 , resting upon feeler gauges with guitar saddle installed and prepared for final sanding procedure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    The preferred embodiment of the precision clamping apparatus  10  of the present invention will now be described with reference to  FIGS. 1-6 . 
         [0017]    Referring to  FIG. 1 , a preferred embodiment of the precision clamping apparatus  10  is comprised of a base  12 ; clamping bar  16 ; roll pins  18  for holding clamping bar in place; internal clamping face  40 ; shoes  14 , which are replaceable after excessive wear; socket cap clamping screws  22 , preferably #8-32×¾″ 304 stainless steel, for tightening clamping bar  16 ; and pushpin  20 . Preferably, the base  10  is made of aluminum 6061, approximately 1.5″×1.5″×3.25″ in size, although other sizes and materials may be utilized. The clamping bar  16  fits in the horizontal leg of the L-shaped slot in base  12 , allowing clamping bar  16  to move freely from front to back. Preferably, the clamping bar is made of ¼″×¼″×3.58″ stainless steel key stock. A ball plunger  38  secures pushpin  20  in its storage hole when pushpin is not in use. 
         [0018]    Referring to  FIG. 2 , a full view of push pin  20  is shown, preferably measuring 0.062″ in diameter and approximately 1.38″ in length and with a knurled knob on top. Preferably, the push pin  20  is made of CRES 300 series stainless steel. 
         [0019]    Referring to  FIG. 3 , the shoes  14  are preferably 0.672″×3.25″×0.063″ in size and made of CRES 300 series half-hard or full-hard stainless steel, although other hard materials may be utilized. The shoes  14  are secured with screws  24 , preferably 18-8 stainless steel 100 degree flat head Phillips machine screws, 4-40 thread, ⅜″ length. In a preferred embodiment, the right and left side of the clamping bar  16  will be kept in place using two roll pins on either end, preferably 1/16″×½″ stainless steel. Also, the bottom side of the clamping bar is held in place by the front side shoe. 
         [0020]    Referring to  FIG. 4 , a guitar saddle  28  is shown clamped in the precision clamping apparatus. Push pin  20  is shown in its storage position. 
         [0021]    Referring to  FIG. 5 , shoe guard  26  is shown, preferably CRES 300 series stainless steel 0.018″ thickness, along with hand-held electric rotary tool  30  and sanding drum attachment  32 . 
         [0022]    As shown in  FIG. 6 , a preferred embodiment of the precision clamping apparatus  10  is shown resting upon two equivalent stacks of feeler gauges  34  in order to set the amount of saddle material to be removed equal to the height of the feeler gauge stacks. 
         [0023]    The sum of these parts that make up the preferred embodiments of the precision clamping apparatus function in unison with the feeler gauges and flat sanding surface. 
         [0024]    The following is representative of the process employed when using the precision clamping apparatus  10  according to a preferred embodiment: 
         [0025]    1. After determining the amount needed to be removed from guitar saddle  28 , create two stacks of feeler gauges  34  of equivalent height as shown in  FIG. 6 . When installing a Fishman Matrix Pickup, for example, to maintain current action on a guitar, remove 0.053″ from the bottom of the saddle per manufacturer&#39;s instructions by making two stacks of feeler gauges 0.053″ each as shown in  FIG. 6 , set on a flat surface, preferably a 12″×12″ granite plate. 
         [0026]    2. To insert saddle as shown in  FIG. 4 , turn base  12  so that clamping screws  22  face downward in order to prevent saddle from dropping below clamping bar. Slide saddle into slot so that bottom of saddle is flush with shoes and finger-tighten clamping screws. 
         [0027]    3. As shown in  FIG. 6 , set precision clamping apparatus  10  on feeler gauge stacks  34 , each stack 0.053″ in height, so that the shoes  14  rest upon the feeler gauges. 
         [0028]    4. Loosen socket cap screws  22  so that saddle drops onto flat surface, preferably a 12″×12″ granite plate. While holding the precision clamping apparatus  10  firmly down on feeler gauge stacks, use index finger to push down on push pin  20  to seat saddle down on flat plate. 
         [0029]    5. Use appropriate hex wrench to re-tighten socket cap screws  22  firmly so that only that portion of material to be removed from saddle  28 , in this case 0.053″, extends beyond shoes  14  as shown in  FIG. 6 . Pushpin  20  can now be stored as shown in  FIGS. 3-5  in storage hole  36  as shown in  FIG. 2 . 
         [0030]    6. Referring to  FIG. 5 , if removing more than 0.018″, first remove the bulk of the material off the bottom of the saddle  28  using the optional shoe guard plate  26  and electric rotary tool  30  with drum sander attachment  32 . Otherwise, proceed to the next step. 
         [0031]    7. The saddle is now ready for the final sanding procedure. Tape a sheet of sandpaper to a flat surface (preferably a 9″×11″ sheet of 150 grit silicon carbide affixed to a 12″×12″ granite plate as was used to support the feeler gauge stacks  34 ). Holding the precision clamping apparatus  10  in your hand, sand the bottom of the saddle until no more material can be removed. You are now finished. For example, if you are installing a Fishman Matrix pick up, you will have uniformly removed precisely 0.053″ from the bottom of the saddle. 
         [0032]    The total process takes about 5 minutes. 
         [0033]    When using the precision clamping apparatus  10 , the individual or guitar luthier will be able to take precise amounts off the bottom of a guitar saddle while avoiding mistakes and eliminating the need for extraordinary skills. In some applications, such as crafting one&#39;s own saddle, a pencil line or scribed line may be preferred and the feeler gauges will be unnecessary. For this method, the saddle can be installed in the precision clamping apparatus  10  finger-tight, and the mark on the saddle can be lined up with the bottom of the back shoe  14 . 
         [0034]    The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention. The present embodiment is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.