Professional Jeweler Archive: Installing Pin Stems

October 2001

Professional Bench/Defining Quality


Pin Stems

Knowing how to professionally install this component of jewelry demonstrates another aspect of quality in your shop


Knowledge of the four basic components of a pin stem will help you properly communicate details to everyone involved in the take-in of a piece of jewelry for repair or in planning for a custom order. Here is a review of the components of a pin stem.

Pin Stem Nomenclature

1. The pin stem
2. The joint
3. The catch
4. The rivet wire

The Pin Stem

Pin stems are made two ways – wire and die-struck.

Wire Stems

These usually made of base metal, are reserved for costume jewelry and have a preset rivet pin. The unit is installed simply by pinching it into a joint.

Die-Struck Stems

These are stamped out of metal stock, so they are stronger than wire stems. They come in two varieties – bearing (top) and no-bearing (above) – and are used for fine jewelry.

Bearing stems have a heel that acts as a cam. When the stem is lowered, the heel prevents the stem from reaching a complete horizontal position. The stem maintains an upward angle of 10&Mac251;-15.&Mac251; This angle, called the stance, helps keep pressure between the tip of the pin and the catch, locking the stem in place.

No-bearing stems have no heel. They are used in short, tight areas less than one inch long. In tight areas, a stance would place too much pressure on the stem.

Catches

Like the pin stem, the catch has its own unique features and comes in two styles – side opening and top opening.

Side-Opening Catches
These work best with bearing stems. The side opening provides an added measure of security.

Top-Opening Catches
These are used in conjunction with no-bearing stems. This combination is perfect to span short distances where tension is not allowed.

The bullet-shaped profile of the catch is a safety feature. The elongated end helps conceal the sharp point of the pin, preventing it from snagging fabric or pricking skin.


Spinning Lock
Encased in the catch is a spinning lock mechanism that holds the pin’s point in place. This locking mechanism is called the rotor.

Installation of Pin Stems

The installation of pin stems can be tricky, but if you follow these helpful hints, everything should go fine.

Soldering the Catch

In soldering the catch to the brooch, one of the main difficulties is keeping the solder from flowing into the catch and freezing the rotor. To help prevent this:

1. Mix a small amount of yellow ocher with water and carefully apply it to the inside of the rotor. The solder will not flow past the ocher.

2. After marking the catch’s position on the brooch, apply a small chip of easy solder to the brooch and melt it in place. Solder is not initially applied to the catch.

3. As you heat the solder, carefully bring the catch into place and solder it. Be careful not to overheat the catch mechanism.

4. Don’t quench pin stem components after soldering. Allow the brooch to air-cool before pickling. This will avoid annealing the pin stem.


Aligning and Soldering the Joint

Here are two examples of how to orient the joint in relationship to the catch.

For a side-opening catch and bearing pin stem, the joint should be fixed at a 10&Mac251; angle to the catch.

For a top-opening catch and no-bearing pin stem, the joint and catch will be in line with each other.

Solder the joint using the same method as for the catch.


Riveting the Pin Stem

Riveting is a common procedure that all jewelers should know. A note of caution is warranted when riveting pin stems. It’s very important not to overtighten the rivet and crush the opening of the joint onto the pin stem. Once riveted, the stem should slide freely in the joint without binding.

After polishing and cleaning, lightly oil the pin stem components to keep them moving freely.

For more information on alternative non-soldering methods of attaching pin-stem components to jewelry, see this month’s “Path to Proficiency,” page 126.

Special thanks to Ron Spain of B.A. Ballou for input on this article.

By Tom Weishaar, JA® Certified Master Bench Jeweler,™ Shop Manager, Underwood's Fine Jewelry, Fayetteville, AR

This information is required for the second level of the JA® Bench Jeweler Certification™ program. For information related to JA’s bench jeweler certification program, call (800) 223-0673.

©2001 Jewelers of America
Illustrations by Lainie Mann – Visual Communications

The JA® Professional’s Guide to Fine Jewelry Craftsmanship

Installing Pin Stems

By Mark B. Mann, Director of Trade programs, Jewelers of America®

Professionally Installed Pin Stems
A. The rotor should spin freely inside the catch. A light oiling after a thorough cleaning is advised.

B. The tip of the pin should not protrude from the catch where it could snag fabric or skin.

C. The joint should not be crushed onto the pin stem. The stem should pivot freely inside the joint.

D. Bearing pin stems should have the correct stance and should be oriented slightly above the catch to add tension.

E. The pin stem wire should be rigid, not soft or annealed.

Potential problems to watch for


This pin was annealed or made from soft wire. While being worn, it was bent and became misaligned. Now the pin could be lost when worn.

This pin is too long and will catch on clothing and skin.

This joint was overhammered when assembled, preventing the pin from swinging freely.

The rivet wire for this joint and pin stem assembly is too small in diameter. It will become dislodged, and the pin will be lost during wear.
This information is required for the second level of the JA® Bench Jeweler Certification™ program.

© 2001 Jewelers of America Inc.
Illustrations by Lainie Mann – Visual Communications


Copyright © 2001 by Bond Communications