SIZE MATTERS (aka Embossing)
Hello Harp Techs,
There are numerous skills that must be mastered, then applied to the art of customizing a diatonic harmonica.
In particular, is a technique developed by former Hohner USA Technician, Rick Epping. As an accordion technician, he had discovered that by decreasing the air gaps surrounding the reed, he could reduce air loss, increase compression, and ultimately improve the playability of the accordion.
He surmised that his “embossing” (a.k.a. burnishing by Richard Sleigh and sizing by Kinya) technique could improve the performance of the Hohner diatonic harmonica as well.
I believe Rick told me, during our 2005 interview, that during the late 70’s, or early 80’s he had discovered that the Hohner factory tooling--dies and punches--used to create reed plates, had essentially wore out after years of use. Harmonicas produced during this period were manufactured with over-sized reed plate slots, resulting in “leaky” (air) and barely playable harmonicas.
As it turned out, Rick’s theory proved accurate, and by correct sizing the out-of-the-box harmonica reed plates--Hohner harmonicas of that era were able to be restored to exceptionally well playing instruments. (a collective debt of gratitude to Rick Epping, Joe Filisko and Richard Sleigh).
In recent years, Hohner tooling has again achieved world class status (Thank you Rick!), but with today’s demand for ultra high performance harmonicas, reed slot sizing continues to be an important skill for the Harp Tech to master.
Shown in this photo is the Richard Sleigh advanced harmonica light table. The dimming switch adjusts the output of the LED lamp--to accommodate any level of ambient lighting. The tiltable wooden slotted panel is used for reed sizing (also notice the slot that will allow you to plink reed in place), and the swappable white acrylic panel is used during the reed profiling process. The cube shaped prism aims your eyes for true center, and the convenient wax well and felt lubricates the tool edges to mitigate chattering and bouncing during the sizing process.
When working with Richard Sleigh’s harmonica light box, or an artist’s sketching light box you will easily see light shining through the sides and surrounding the tip of the reed. The goal is to reduce as much light (air gap) as possible--without touching the reed (or the reed will catch, click and buzz when vibrating through the slot!),
The reed plates are made of brass, significantly softer than the carbide tipped or stainless steel reed slot sizing tools. This will enable you to push over, or “waterfall the slot edges” of the reed plate, over and into the reed slot. It will appear you are stretching the surface edges of the reed plate into the slot, and therefore, shrink the size of the slot. Yes, it is hard to imagine, but true!
Support the free end of the reed with a plinking tool (shim). Using the thickness of the reed as a fence guide, position the Richard Sleigh reed slot “burnishing” tool into the crevice located into the upper most corner of the reed plate slot--where the rivet reed plate pad meets the reed.
Similar to painting a straight line, without the benefit of masking tape, carefully slide the tool towards the free end of the reed, never take your eyes off the diminishing sliver of light. This will provide you feedback as to how much metal (brass) you have pushed into the slot.
Apply the same strategy at the tip of the reed plate slot. Be careful not to overdo it, otherwise the vibrating reed will definitely encounter a burr!
Turn the reed plate around and repeat the sizing process.
Shown here, I apply the same techniques, except now with the original Dick Sjoberg UST (Ultra Sizing Tool)
Working my way down towards the tip of the reed plate slot.
Again turn the reed plate around and repeat the process.
Dick Sjoberg’s UST
For me, the magic in both Dick Sjoberg’s UST, and Richard Sleigh Reed Slot Burnishing Tool is the subtle radius of the tool’s edge. This allows more control (read:rolling) when manipulating the brass, without the annoying and sloppy tool “chatter” often experienced with straight edge (right angle) type tools.
I sincerely hope this brief photo essay enlightened you as to why SIZE MATTERS.
For reference, watch our tutorial, Harp Tech Series #6, "Reed Slot Sizing". At the top of this page, select EQUIPMENT, then scroll all the way down to the basement, "HARMONICAS". Let me know your progress!
Your Harpsmith, Kinya
