Fitting the Saddle to the Spider Bridge

The Mechanics Matter. Replogle Reso parts are designed to meet close tolerances, with an eye toward the best fit as well as proprietary designs and quality materials. 

“A good fit supports the audio mechanics of the resonator guitar and optimizes the sound”, says Mike Replogle, “and when the parts fit properly together, the complex resonator structure projects tone with excellent sustain and without buzzing or extraneous noise and vibrations”. 

A Glue-free Environment. Well-built parts that fit together properly ensure that glue is not required (or recommended).  Replogle Saddles are designed to be snugly fit into the bridge slot by hand and without adhesive. Mike Replogle says, 

“… the temptation is always to glue everything together. And usually with super-glue. Although there definitely is a time and place for glue, with reso parts it’s usually a corrective process- meaning, fixing something that doesn’t fit or that is broken. My philosophy it to build it right in the first place!  … Especially with reso-guitars, the resophonic pieces all fit together as a unit under the string pressure- cone, bridge and saddle- and they work best when they are allowed to function organically and without glue creating an arbitrary bond or sonic interference.”

Fitting the Saddle to the Spider Bridge

Pressure Fit. Replogle Saddles are designed to be lightly sanded and pressure-fit by hand into the spider bridge slot. As noted, a good, snug fit optimizes the vibrational mechanics of the resonator guitar and delivers the best sound– (glue is not required or recommended). 

Adjusting the Saddle Thickness. The Replogle saddle itself is made slightly thicker than ⅛”, in order to allow for a bit of hand-sanding to create a snug pressure-fit. The saddle will Not fit in the spider bridge slot until the saddle is final-sanded during installation. 

Sanding the Saddle. Use 80 or 120 grit sandpaper to hand-sand and thin the lower portion of the saddle where it will mount in the spider bridge slot. This can be done by sanding the sides lightly by hand– a small sanding block is recommended to keep the sanded side smooth and level. 

A Few Notes on Sanding…

  • It is not necessary to sand the entire side of the saddle, rather just the lower portion that will be pressure-fit into the spider bridge slot. 
  • Sand the saddle in phases- do not attempt to sand the full thickness in just one pass. 
  • Check the fit frequently. It is very important to sand a little, then check the thickness and the fit in the saddle, then sand again and check- repeating the process until the saddle will go into the spider bridge slot when pressed firmly, but can still be removed by hand.
  • The spider bridge slot holds the saddle in place and keeps it perpendicular- be sure to keep the saddle surfaces flat and square when sanding.
  • It is Not necessary to glue the saddle into the spider bridge slot when it is properly fit. 
  • Avoid over-sanding that will make the saddle too thin and allow it to wobble in the bridge slot — this situation will result in the need for the use of glue to mount the saddle.

Mounting the Saddle. The saddle is mounted in the ⅛” slot cut in the top of the spider bridge. The saddle is pressed firmly by hand (do not use a hammer or mallet) into the saddle slot, keeping the saddle perpendicular to the base of the spider bridge. Note that the saddle will need to be cut into two parts on the centerline- see instructions below

Truing the Bottom of the Saddle. It is very important that the bottom of the saddle is completely square and flat once the height has been adjusted as per the steps outlined below. A sheet of sandpaper laid on a flat table (such as a drill press table, table saw, etc) can be used carefully for final truing up of the bottom of the saddle once the proper height adjustment has been achieved. It is recommended to use a square or sanding block to hold the saddle perpendicular when truing the saddle base. Stewart MacDonald has a great jig for use with a belt sander, the Nut & Saddle Sander 

Saddle String Spacing. The overall string spacing ranges from 2 ⅜” – 2 ½” total width and is commonly about 2.25” from the 1st string to 6th string (center-to-center). However, the string spacing varies with models and manufacturers, and also greatly according to the individual player’s preference.  

As an example: with a 2.25” total spacing, then dividing that by 5 gives an individual string-to-string spacing of .450″, and it would then be 1.125” from the center of the tension screw to the 1st and/or the 6th string.  

Measure and mark the position of each string’s spacing on the saddle with a pencil for reference. 

Shaping the Top of the Saddle (non-compensated saddle blanks only). The top of the saddle “blank” is left flat and non-slotted so that it can be shaped for the player’s preference. Shaping the top  is done before slotting, and the crown of the saddle is usually rounded or bullet shaped when done. The shape of the saddle top can affect the intonation. Note that “compensated” saddles are pre-formed and shaped, so no additional shaping is required although they will need to be slotted to hold the strings according to the player’s spacing preference. 

Slotting the Saddle. Each wound string slot should be just deep enough so that half the diameter of the string rests in the slot. Plain strings are thinner, so they are usually slotted somewhat deeper, with the top edge of the string just clear of the saddle slot or flush. Note that if the slots are too large, then the  strings will sustain poorly and may buzz or rattle in their slots. If the slots are too small, then  they can pinch the string and cause buzzes and cause problems when tuning.

Saddle Height Adjustment. The height adjustment process is done by removing wood from the bottom or the top of the saddle, depending on the style of saddle as noted below:

Saddle Height Adjustment- Blanks . One-piece saddle blanks (no ebony cap & non-compensated) may be sanded from the top edge to adjust the saddle height. This is the easiest style of saddle to work on and the general process is as follows:

Before cutting the saddle into two pieces… 

  1. Place the cover plate, resonator and spider bridge (without the saddles and without the tension screw installed) into position on the guitar.
    1. Note: since the tension screw is not installed to hold the spider and resonator together at this stage, be Very Careful to keep the spider properly positioned on the resonator to avoid damage to the cone
  2. Measure the distance from the bottom of the slot in the spider bridge center tab to the top edge of the coverplate palmrest strap (this measurement is the maximum height of the saddle).
  3. Measure from the bottom of the saddle and mark the maximum height measurement on the saddle with a pencil. 
  4. Trim the height of the saddle by sanding or filing it down to the marked pencil line. Use a straight-edge or metal ruler to be sure that the top edge of the saddle is straight.
  5. Seat the saddle firmly in the spider bridge saddle slot (see, “Adjusting the Saddle Thickness” and “Mounting the Saddle” above). 
  6. Mark and then notch the slot positions of the strings on the top of the saddle- cutting only deep enough just to hold the string in position but not fully seated.

And now…. 

  1. Cut the saddle in the center into two pieces to allow for the “tension screw gap”. It is recommended to use a very fine tooth saw or fret saw to minimize the loss of saddle from the cut. The following is an example of the type of saw to use (Amazon affiliate link)
  2. Seat the two saddle pieces firmly in the spider bridge slot, making sure that both saddle pieces are the same height and straight- check with a metal ruler. 
  3. Attach the spider bridge to the resonator, using the tension screw through the top center-hole of the spider bridge and screwing it into the threaded hole on the bottom of the spider- finger tight only after first tension!
  4. Position the resonator assembly– placing the spider cone with bridge & saddle in the soundwell
  5. Put the coverplate in place, and thread 3 screws spaced apart on the coverplate in the 12/4/8 positions to hold it in place
  6. String up the guitar, starting by placing the 1st and 6th strings in the saddle slots and evenly increasing the string tension on alternate strings to keep the string pressure evenly spread out on the cone while tuning.
  7. Bring the guitar up to pitch, and check the string clearance – the string pressure will pull the cone down slightly, and that should be enough to allow the strings to clear the edge of the palmrest while being at their maximum possible height. 
  8. If the strings are touching the palmrest, then adjust the string height down by lowering the saddle height- repeating the necessary steps above until the height is correct and the strings clear the palmrest.
  9. Once the saddle height is correct, to complete the setup the guitar will need to be disassembled, and the saddle will need to be properly shaped and fully slotted before final reassembly.

Saddle Height Adjustment- Capped, Radius and/or Compensated Saddles. For Replogle Saddles that have an ebony cap, a radius and/or compensation, the height adjustment must be done by removing wood from the bottom of the saddle where it will mount in the spider bridge slot. This may be done by hand sanding, or using a sanding machine. 

Before cutting the saddle into two pieces… 

  1. Place the cover plate, resonator and spider bridge (without the saddles and without the tension screw installed) into position on the guitar.
    1. Note: since the tension screw is not installed to hold the spider and resonator together at this stage, be Very Careful to keep the spider properly positioned on the resonator to avoid damage to the cone
  2. Measure the distance from the bottom of the slot in the spider bridge center tab to the top edge of the coverplate palmrest strap (this measurement is the maximum height of the saddle).
  3. Measure from the center-top of the saddle, downward and mark the maximum height measurement on the saddle with a pencil. 
  4. Trim the bottom of the saddle by sanding or filing it up to the marked pencil line.
  5. Use a straight edge or metal ruler to check that the sanded saddle bottom is straight and flat. 
  6. Seat the saddle firmly in the spider bridge saddle slot (see, “Adjusting the Saddle Thickness” and “Mounting the Saddle” above).
  7. Notch the slot positions of the strings on the top of the saddle, deep enough just to hold the string in position, but not fully seated.

And now…. 

  1. Cut the saddle in the center into two pieces to allow for the “tension screw gap”. It is recommended to use a fine tooth saw or fret saw to minimize the loss of saddle from the cut.
  2. Seat the two saddle pieces firmly in the spider bridge slot. Use a straight edge or metal ruler to check that the two saddles are even and flat with respect to each other.
  3. Attach the spider bridge to the resonator, using the tension screw through the top center-hole of the spider bridge and screwing it into the threaded hole on the bottom of the spider- finger tight only!
  4. Position the resonator assembly– placing the spider cone with bridge & saddle in the soundwell.
  5. Put the coverplate in place, and then thread 3 screws-  spaced apart on the coverplate in the 12/4/8 positions – to hold it in place
  6. String up the guitar, starting with the 1st and 6th strings and evenly increasing the string tension on alternate strings to keep the string pressure evenly spread out on the cone while tuning.
  7. Bring the guitar up to pitch, and check the string clearance – the string pressure will pull the cone down slightly, and that should be enough to allow the strings to clear the edge of the palmrest while being at their maximum possible height. 
  8. If the strings are touching the palmrest, then adjust the string height down by lowering the saddle height- repeating the steps above until the height is correct and the strings clear the palmrest.
  9. Once the saddle height is correct, to complete the setup the guitar will need to be disassembled, and the saddle will need to be properly slotted before final reassembly.

Slotting the Saddle.  Once the resonator guitar saddle has been adjusted for height and the bottom has been trued and the saddle has been pressed into the spider bridge slot, then the finished saddles need to be properly slotted to set the strings . 

  1.  The guitar will need to be disassembled to give access to the saddle for slotting: 
    1. Remove the strings 
    2. Remove the coverplate. 
  2. Slot the saddles;
    1.  Finally, once the saddles are properly slotted for the strings, then guitar may be re-assembled for the final time. 

Note: It is important to have the strings exert even pressure on the cone as the resonator guitar is tuned up, please refer to “Replacing the Strings”.