Repairing and Sizing Expansion Bands

December 1998

Timepieces:Education & Repair

Repairing and Sizing Expansion Bands

A few basic procedures can expand your repair abilities and draw a wider range of repair traffic

By David Christianson
Certified Master Watchmaker
President, American Watchmakers-Clockmakers Institute

Speidel's "Twist-o-Flex" and other expansion bands remain as popular as ever – your store no doubt sells or repairs many of them. You may be called on to custom-fit an expansion band that comes with a new watch. Other times the band breaks when a customer catches it on something, and you have to replace it or – if it's one of today's higher-priced versions – repair it. Sizing the band and repairing the links are performed using the same basic procedures.

Removal Procedure
Expansion bands are made of a series of bottom and top rectangular, tube-shaped links holding two leaf springs and four U-shaped clips per link. On top is a decorative cap.

To start the repair, you'll need a thin knife blade. Place the blade behind the flat end of a link and twist outward while pushing toward the fold in the hinge (see below). To remove the U-clips, use the knife to lever open the end of a top cap on one link and then open the opposite end on the bottom link on the adjoining link. Slide the two halves apart and the U-clips will be clear to grasp with tweezers.

Another method is to open the ends on both sides of the top cap and adjacent bottom link. Using tweezers, slide out the connected U-clips.

To begin the repair, use a thin knife blade to pry open the flat end of the link.
(Note: Several Speidel expansion bands require complete removal of the top caps before replacing a link. These have larger top caps or an angled end flap. If in doubt, refer to the watch company's repair guides.)

To replace the U-clips after sizing or repair, line them up. Be sure the clip on the bottom link inserts above the leaf spring in the top cap. Also be sure the clip from the opposite end inserts below the leaf spring on the bottom link. Slide the two links together. This can be tricky, but you'll be able to do it in fewer than 10 minutes with practice.

When closing the ends of the links, support one side on your bench top. Apply even pressure as you rotate your blade downward. When both sides are closed, place the band in a small, smooth-jawed bench vice. Close the jaws slowly to even out the closed end flaps.

Fitting the Band
A properly fitted expansion band should have no gaps between the links when placed on the wrist. If there's a gap, add a link. (Or recommend buying a larger size.) Otherwise the band will bind the wrist, pull hair and be uncomfortable.

When sizing, hold the band around the customer's wrist (see below) and count the number of links that "bunch up." Subtract two from this number and remove the remaining links using the procedure outlined above. Open the band, count out the links for removal, slide them out and rejoin the two halves.

To size a band, wrap it around the wrist, count the extra links and subtract two.
After a few years of use, expansion bands begin to weaken and gaps appear between the links. Dirt and perspiration aggravate this deterioration. When an older band becomes uncomfortable, you can extend its life for a year or so by removing several links. Afterward, the links usually become so weak that replacement is the best answer.

David Christianson is fourth-generation owner of Christianson Jewelry, Kendallville, IN. In addition to serving as president of AWI, he's a certified master watchmaker and a fellow of the British Horological Society. He discusses watch repair for the sales staff in this column each month. Questions, suggestions and comments can be sent toProfessional Jeweler,1500 Walnut St., Suite 1200, Philadelphia, PA 19102, e-mail askus@professionaljeweler.com.



Copyright © 1998 by Bond Communications.


 

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