G-S Supplies Inc.

100 Years of innovation, support, and service for watchmakers

By Donna Hardy

Kathye Simon with her father, Leonard Simon, who provides engineering support, works on new product development, speaks with customers, and shares his expertise.

Kathye Simon with her father, Leonard Simon, who provides engineering support, works on new product development, speaks with customers, and shares his expertise.

G-S Supplies, based in Rochester, New York, has been serving watchmakers for 100 years. If you’re a watchmaker, you’ve probably bought their crystals, tools, or adhesives at some point in your career. Perhaps you did not know they offer much more, such as custom manufacturing services—coating, etching, and printing services, as well as custom-made crystals.


Kathye Simon is not only the CEO of G-S Supplies, she is also the granddaughter of Julius Simon, co-founder of Germanow-Simon Machine Co., the forerunner to G-S Supplies, a family-owned business. She says, “I like to say that I started working for the company when I was five years old, when I began accompanying my father to work a few times each year to help pack watch crystals in envelopes.”   


Simon started working full-time at the company in 1991.  She worked on special costing projects related to production, and then served as the accounting manager for several years. She took over as General Manager of the Watch Crystals and Supplies Division in 1997. In 2007 G-S Supplies spun off from the Germanow-Simon Companies, and it is now an independent entity. At that time, Simon assumed the role of CEO. 


Below, Kathye Simon answers some questions about G-S Supplies for American Timepiece:

Rows of crystals ready to be sold.

Rows of crystals ready to be sold.


Are all of your products made in the United States?

All cement production and a significant amount of our plastic watch and gauge crystal manufacturing takes place here in Rochester. We import some plastic crystal styles from long-time partners in Europe, and we import all mineral glass and sapphire primarily from a production partner in Asia.

What are some of the companies that distribute your products in the US and abroad?

Most watch material distributors in the US and Canada distribute our watch crystals and adhesives. We have customers in every region of North America. We sell our adhesives to distributors in the watch and jewelry industry, to master distributors and retailers in the hobby and craft industries, and to production facilities for precision assembly applications both in the US and internationally.

Can watchmakers buy crystals and other products directly from you, or only from your distributors?

We have a very strict policy about offering wholesale prices only to those customers who purchase our minimum-order quantity. We sell to many manufacturing jewelers who utilize our watch crystals in different types of jewelry designs, both small and large volume. We enjoy working with our large distributors and long-time customers, and with engineers and designers planning new watch, gauge, and jewelry projects.

What is the largest sector of your business?

Our adhesives, G-S Hypo Cement and G-S Hypo Fabric Cement, now make up the largest segment of our business. Two additional adhesives are in development at this time. These adhesives are sold world-wide into a variety of industries.

How many people does G-S Supplies Inc. employ?

We employ five people at our Rochester office/production facility. Due to increased sales of G-S Hypo Cement and regulatory changes in the chemical industry that would have required a major plant reconfiguration, some of our production equipment (cement mixing, filling, and packaging) is now located at specialty chemical processing companies in the Rochester area.

Can you tell me about your custom manufacturing of watch crystals?

This is a rapidly growing segment of our business. In addition to manufacturing vintage crystal designs for classic watches, we manufacture crystals for new watch and gauge designs, for jewelry, for readout displays, and for wearable technology devices. We offer design services and custom engineering in mineral glass, sapphire, Gorilla glass, and plastic.


This year is the 100th anniversary of the company. How has it developed over the last 100 years? Is the company making different products than it was when it started? How has it innovated, and what has it contributed to the industry that is unique?

The company has evolved in many ways over the last 100 years.

Watch Crystals

Molding of "PA" style crystal at G-S.

Molding of "PA" style crystal at G-S.

-          After supplying machined parts during the WW I, we responded to a need for replacement crystals in the US when trade with Europe was cut off.

-          As wristwatches became more popular, we began manufacturing sets of watch crystals, using the earliest types of plastic. We then sold them to watchmakers and repair shops throughout the US.

-          As plastic materials improved, we updated our production processes and continued to expand the watch crystal styles and range of sizes that we manufactured, ultimately distributing master cabinets filled with thousands of crystal sizes.

-          We worked with many major watch brands through the years, including Bulova, Hamilton, Gruen, and others, to ensure that G-S replacement crystals were manufactured to their design specifications.

-          We began to partner with production facilities in Europe in the 1960s to continue to expand our crystal selection. We began distributing mineral glass crystals in the 1970s. We maintain a complete inventory of all popular sizes, while continuing to supply a wide variety of different types of crystals in virtually all styles. We discuss current trends with our distributors and make every effort to keep our crystal stock current with the latest fashion trends. We continue to expand our selection annually, based on our customers’ recommendations.

Tools and Machined Products

Quality Control: All parts are inspected to engineering prints.

Quality Control: All parts are inspected to engineering prints.

-          In our early years we manufactured some fascinating and unusual products, including wheel bearings for horse-racing sulkies, a handheld plastic perfumed fan, and a typewriter-mounted eraser.

-          We developed crystal-fitting tools and accessories, including the G-S hand press and watch crystal gauge. A modified version of the crystal inserting tool, known as the foot press, was also developed. This press was mounted on a crystal cabinet with a foot pedal, leaving the watchmaker’s hands free to fit the crystal.

-          We now distribute many tools, both for professionals and beginners, for watchmaking, jewelry making, hobbies and crafts. These are sold at ToolsGS, our online store at Amazon.com.


G-S Hypo Cement, developed in the 1930s, continues to be a top seller today.

G-S Hypo Cement, developed in the 1930s, continues to be a top seller today.

-          G-S Hypo Cement, with its built-in precision applicator was developed in the 1930s to meet the needs of watchmakers to cement crystals in place neatly and cleanly. Remarkably, the cement formulation and tube design have remained virtually the same since this time, though our manufacturing equipment and processes have been updated through the years.

-          We developed G-S Hypo Fabric Cement in 2003 in response to a demand for an adhesive for decorative textile and paper applications (bridal, costuming, card-making, etc.).

-          Our adhesives are sold throughout the world by distributors, retail chain stores, and individual hobby and beading shops. We introduced the G-S Hypo Cement 10-pack carton in 2009, making it easier for retail outlets to display our product in multiple areas of their stores.

-          We continue to research and develop other specialty precision adhesives and hope to release two new products within the next one to two years.

Custom Manufacturing Services

Sample of emerald-cut custom glass design produced for manufacturing jeweler.

Sample of emerald-cut custom glass design produced for manufacturing jeweler.

-          We began offering custom plastic and glass manufacturing services in 2000. With our in-house engineering, material, and design expertise, we have assisted hundreds of customers with production of crystal replicas for antique watches; replacement crystals for classic watches; prototype production for designers; limited-quantity production for unique and unusual jewelry and watch designs; and large-volume production quantities for jewelry, instruments, and wearable technology. We also manufacture watch gaskets and other related components for customers, sourcing through our long-time contacts in the industry.

-          We continue to offer custom manufacturing services with an expanded number of materials. We also offer standard and custom coatings, printing, and etching services.

Customer Service

-          Our original logo includes a banner across the top that says “Precision” and “Service,” and these continue to be primary values at G-S. The quality of our products and superior customer service remain at the core of who we are. We are pleased to be able to celebrate 100 years of innovation at G-S.