Cutting Pattern

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CUTTING PATTERN TO MOTHER OF PEARL

Now comes the fun part of getting your cutting pattern onto the mother of pearl blanks.  Gibson in the pre-war days had thin metal zinc plated scribe inlay templates for each inlay design and placed the template onto the mother of pearl blank and scribed around the template with a small metal scribe and later inked the scribed lines in which is a hard way to do it.  I expect if one was use to cutting to the thin scribed line since it would be much thinner than the actual width of the jewelers saw blade, one could cut a very accurate pattern.  I have seen some pre-war wreath patterns enlarged four or five times that were still nearly perfect;  however there were many that were cut crude by my own standard!  The zinc pattern method that Gibson used to transfer a pattern to the mother of pearl blanks was related to me by George Hall in the early 1970s, a Gibson pre-war employee from 1927 thru 1933 which I mention in the Biography webpage.

In my case, the Porter method, I have a true to scale printed pattern of my Flaming Claw design which has both the fingerboard and peghead inlay patterns and an identical to scale pattern to use when cutting the peghead and fingerboard material to receive the precut inlays.   The first step is to cut around each printed inlay design with a pair of scissors leaving enough black background edge to facilitate cutting next to the white pattern (actual inlay shape).   After years of cutting inlays, I could easily maneuver the material into the saw blade cutting to the edge of the white pattern without any real conscious effort...it just happened being second nature so to speak.  I  will discuss the mechanics of cutting later on.  The above master pattern was cut using this same technique except I stacked and glued two pieces of mother of pearl material together to cut a matching right and left pattern and later photographed and printed the cut inlays for a master pattern to print from.  This technique of stacking multiple inlays does not work for the actual cutting of the inlay for fingerboards since you need the backing to facilitate inlaying the fingerboard, unless you route the cavity.  I have NEVER seen a Gibson pre-war banjo fingerboard that was cannibalized that did not have the exact matching substrate material glued to the inlay pattern  which tells me that they did not stack multiple fingerboard inlay pieces; however, it would be possible to stack multiple banjo headstock inlays since Gibson did not use a backing substrate when inlaying the pegheads due to the veneer thickness being about the same thickness as the inlays, but I do not believe they cut stacked inlay material from my personal experience of cutting inlays off an on for over four (4) decades due to the difficulty of cutting the inlays,  the distortion between the top and bottom pieces in a production environment and you can only stack so much material due to the stroke or cutting length of the machine that holds the standard jewelers saw blade. 

 

I have used several methods to apply the cutting pattern to the inlay material but have found that Scotch brand clear double stick tape worked the best for me.  Many fine Craftsmen use rubber cement but this is the Porter method.  One inch width clear double stick is the best width to use but the last roll I purchased was only 3/4 inch wide and do not like it as well because it takes four strips instead of three to cover the inlays and substrate material.  I first apply the double stick tape to the entire mother of pearl making sure you do not have any area that is not covered, otherwise your pattern might come loose in the middle of cutting a critical area and that is bad news for sure with the high dollar cost of the mother of pearl raw material today!  I use a small utility knife or X-Acto type small blade and try and fit the larger patterns onto the mother of pearl first.  I will "eye" the piece before actually placing the pattern down onto the double stick tape and when I am satisfied, I will position the paper cutting pattern onto the mother of pearl blank.  After fitting the larger cutting pattern pieces onto the mother of pearl, I will then fit the smaller pieces in.  Be sure and leave several saw blade widths between your pattern.  It is best not to be too frugal and give yourself plenty of room between the more delicate designs.  A little trick when getting all the cutting patterns onto the mother of pearl blanks, use your finger as if you were being finger printed or in my case finger printing someone; in other words, roll your finger across the pattern otherwise you will pull the double stick tape up from the mother of pearl blanks.  Do this over the entire substrate material making sure the double stick tape is adhered to both the paper pattern and the mother of pearl inlay blank.  When cutting years ago, there was plenty of pearl and regular dust in the shop and I would sometimes sprinkle some dust over the double stick tape after applying  the paper patterns and this would save some time when pressing down the pattern and double stick tape since it would not stick to your fingers and pull up from the balsa wood substrate material.

Above first two pixs from left to right of the Flaming Claw inlay pattern double stick taped to the mother of pearl and balsa wood substrate material ready for cutting.  The next pix shows some scrap balsa wood and inlay patterns from years back and the pix on the far right is more current inlays that were cut using the above technique and later removed from the balsa wood substrate backing from the mother of pearl and abalone inlays by placing the inlays in boiling water for about 15 to 20 minutes.  Since those inlays will be inlaid using a cavity cut out by a small router instead of the Gibson method of cutting through the entire fingerboard and peghead material, the substrate balsa wood backing is not needed.

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