Seth Thomas #2 Weight Cord Nesting Repair Guide

Seth Thomas #2 weight-driven regulators with brass cable that tangles and nests when weights reach one-third descent present a frustrating problem where the clock stops despite adequate winding. When cable overlaps itself during winding and adjacent wraps climb over each other creating binding knots, the issue stems from improper cable diameter selection, excessive cable length allowing slack conditions, or stiff brass cable memory that resists laying flat on the drum. This common problem affects movements converted from original materials to modern brass cable without considering the fundamental differences between materials. This guide covers complete diagnosis and correction of Seth Thomas #2 weight cord nesting problems. You'll learn how to select proper cable diameter matching drum groove spacing, calculating correct cable length allowing one turn remaining when weights reach floor position, understanding why stiff brass cable creates nesting while flexible braided nylon prevents tangling, proper winding technique maintaining tension preventing overlap and binding, and methods for training cable to accept correct drum pattern through repeated weighted wind-down cycles. The key to preventing nesting is recognizing that brass cable requires careful diameter matching to grooves and perfect winding technique, while solid-braid nylon cord offers superior performance through flexibility and lack of memory that eliminates most nesting problems.

Understanding Cable Nesting Problems

How Nesting Develops

Cable nesting occurs when cord overlaps itself during winding instead of laying in neat adjacent wraps on the drum. The overlap creates a high spot. During subsequent winding, the next wrap encounters this high spot and climbs over it rather than settling beside it. This climbing creates more overlap. The cycle continues building a tangled mess.

Once nesting starts, it worsens progressively. Each winding adds more overlaps. The cable mass becomes increasingly disorganized. Eventually the tangled cable binds so severely that the movement can't overcome the friction. The clock stops despite the weight having substantial drop distance remaining. The stopping typically occurs when the weight is about one-third down.

The nesting doesn't happen immediately after initial installation. New cable winds correctly for some time. Problems develop gradually as the cable develops memory and loses its initial tension. The clock may run fine for weeks or months before nesting becomes problematic. This delayed appearance confuses owners who assume the installation was correct since it worked initially.

Why Brass Cable Nests

Brass cable is very stiff compared to alternatives like braided nylon. The stiffness comes from the material properties and construction. Woven brass strands want to maintain their manufactured shape. When you bend brass cable onto a drum, it resists the curve. The cable constantly tries to return to straight configuration.

This return force causes problems. As the weight pulls cable off the drum, residual spring tension remains in the cable. When you wind the clock, this tension affects how cable lays on the drum. The cable doesn't settle flat naturally. It bridges between contact points creating gaps. These gaps allow overlapping during subsequent windings.

Brass cable has pronounced memory. Once it develops a nested pattern, it remembers that configuration. Even after you carefully unwind and rewind correctly, the cable wants to return to the nested shape it learned. This memory makes brass cable problematic for weight-driven clocks unless installation and winding technique are perfect.

Cable Versus Groove Diameter

Seth Thomas #2 drums have grooves cut in a spiral pattern. These grooves guide cable placement during winding. The cable diameter must match the groove spacing. If cable is too thick, it rides up the groove sides and overlaps neighboring wraps. If cable is too thin, insufficient cable fits on one layer to provide adequate drop distance.

Calculate proper diameter by measuring grooves per inch on your drum. Divide one inch by the number of grooves to get groove spacing. Cable diameter should be a few thousandths under this spacing. For example, if you have 20 grooves per inch, spacing is 0.050 inches. Cable should measure approximately 0.047 inches diameter.

Cable that's even slightly oversized causes problems. The extra diameter seems trivial - perhaps just a few thousandths of an inch. However, over multiple wraps, small errors compound. By the time the drum is half full, significant overlap exists. This overlap creates the conditions for progressive nesting.

Proper Cable Length

Determining Correct Length

Correct cable length allows the weight to descend nearly to the floor while leaving approximately one turn of cable on the drum. This remaining turn prevents the cable end from pulling free during normal operation. It also ensures the cable doesn't go completely slack when the weight reaches bottom, which would cause immediate nesting on the next winding.

To measure for proper length, let the weight down completely until it rests on the floor. Observe how much cable remains on the drum. If no cable remains and the drum is bare, the cable is too short. If multiple turns remain, the cable is too long. One turn remaining represents proper length for most Seth Thomas #2 regulators.

Typical Seth Thomas #2 regulators use approximately 41 inches of cord for proper operation. This dimension accounts for drum diameter, case height, and desired drop distance. However, cases vary. Some are taller than others. Measure your specific clock rather than assuming standard dimensions apply. Cut cable after measuring rather than ordering pre-cut lengths.

Problems from Excessive Length

Cable that's too long creates multiple problems. The excess length means more cable remains on the drum when the weight reaches bottom. This extra cable mass on the drum increases the likelihood of tangling. Each unnecessary wrap provides another opportunity for nesting to develop.

Excessive length also creates slack conditions during operation. As the weight descends, the cable unwinds from the drum. Near the end of the drop cycle, tension decreases. If cable length is excessive, actual slack develops where cable hangs loose. This slack guarantees nesting during the next winding. The loose cable tangles as you wind it back onto the drum.

Long cable wastes material and money. More importantly, it creates service issues. Shortening installed cable requires removing it from the movement. This means taking the clock off the wall, removing the weight, and threading new cable. The job that could have been done correctly during initial installation now requires complete re-work.

Testing Cable Length

Test cable length by operating the clock through a complete wind cycle. Wind the clock fully. Let it run until the weight nearly reaches the floor. Observe the drum when the weight is at lowest position. You should see approximately one turn remaining on the drum. The cable should maintain light tension even at this position.

If the weight reaches the floor with the clock still running, cable length is too short. The weight hitting the floor creates sudden shock. This shock stresses all movement components. You risk breaking pivots or damaging wheels. Always maintain adequate cable length preventing weight contact with the floor during normal operation.

If multiple turns remain when the weight reaches bottom, remove the excess. Calculate how many inches of cable correspond to the extra turns. Measure drum circumference, multiply by excess turns, and cut that much cable off. Test again after shortening. Iterative shortening works better than trying to remove perfect amount in one attempt.

Cable Material Selection

Brass Cable Characteristics

Brass cable offers impressive strength and noble appearance. The golden color suggests quality and authenticity. Many clockmakers prefer brass cable for these aesthetic reasons. However, brass cable has significant functional disadvantages for weight-driven movements, particularly in smaller diameters used for Seth Thomas #2 regulators.

The stiffness that makes brass cable strong also makes it difficult to manage. It resists bending onto drums. It won't conform to grooves naturally. It maintains memory of previous configurations making it hard to correct nesting once it develops. These characteristics mean brass cable requires perfect installation and meticulous winding technique to work reliably.

Brass cable can damage movements over extended use. The stiff material concentrates wear at contact points. Pulleys and drum grooves show accelerated wear from brass cable friction. Some movements develop groove damage severe enough to require drum replacement. The damage accumulates slowly but inevitably with brass cable use.

Braided Nylon Advantages

Solid-braid nylon cord provides superior performance for weight-driven regulators. The material is flexible, conforming naturally to drum grooves. It has no memory - once you wind it correctly, it maintains that pattern reliably. It doesn't tangle or nest under normal conditions. These characteristics make braided nylon the preferred material for most applications.

Nylon's slight stretch actually benefits the movement. The elasticity absorbs shock during winding. When you crank the weight up rapidly, the cord stretches slightly rather than transmitting shock directly to movement components. This shock absorption extends component life and reduces wear. The stretch is minimal and doesn't affect timekeeping.

Braided nylon lasts for decades. Some installations have operated continuously for 60+ years without cord replacement. The material doesn't degrade from UV exposure, oil contamination, or normal wear. While brass cable looks more traditional, nylon's functional superiority and longevity make it the practical choice.

Selecting Nylon Cord Diameter

Choose nylon cord diameter matching your drum groove spacing using the same calculation as brass cable. However, nylon's flexibility means diameter tolerance is less critical. Slightly oversized nylon compresses and conforms. Slightly undersized nylon still provides adequate drop distance because it lays more compactly.

For Seth Thomas #2 regulators, 1.18mm (approximately 0.047 inches) solid-braid nylon works well. This micro-cord size matches most drum groove spacing. It's strong enough for typical regulator weights while being flexible enough to lay flat on the drum. The material is available from parachute cord suppliers.

Verify the cord is solid-braid construction, not hollow-braid. Hollow-braid nylon has empty center tube. Under load, hollow-braid collapses and deforms. The deformation affects how the cord lays on drums. Solid-braid maintains round cross-section under load providing consistent drum winding pattern. Clock supply houses sometimes sell hollow-braid - verify construction before purchasing.

Proper Installation and Winding Technique

Initial Cable Training

New cable needs training before reliable operation. Install the cable on the drum and attach the weight. Remove the pulley or disconnect the cable from the movement so the weight hangs freely. Let the weight down completely. Wind it back up slowly by hand. Repeat this cycle 10-20 times. This training removes cable memory and establishes proper pattern.

During training cycles, maintain constant tension on the cable. Never allow slack. Guide the cable onto the drum with your fingers if necessary. Each training cycle improves how the cable lays on the drum. After sufficient training, the cable accepts the drum pattern naturally without guidance.

Training is especially important for brass cable due to its stiffness and memory. Nylon requires less training but still benefits from several cycles before final installation. The training time investment prevents problems during normal operation. Twenty minutes of training saves hours of troubleshooting later.

Winding Best Practices

Wind slowly and smoothly. Rapid cranking doesn't allow cable to settle properly on the drum. Each wrap should lay beside the previous wrap without gaps or overlaps. Slow winding gives cable time to find its proper position. If you wind too rapidly, cable bridges over gaps creating conditions for future nesting.

Maintain tension throughout winding. Don't release the crank allowing the weight to drop suddenly. The sudden drop creates slack. The slack allows cable to shift and tangle on the drum. Keep slight backward pressure on the crank as you wind. This pressure maintains tension preventing slack conditions.

Never wind partially then release the weight suddenly. This practice guarantees nesting. If you must stop winding partway through, control the weight descent carefully. Or complete the winding fully rather than leaving the clock in partial-wind state. Partial winding followed by rapid let-down is the primary cause of operator-created nesting.

Correcting Existing Nesting

To correct existing nesting, you must completely remove the cable and rewind it properly. Let the weight down fully using the crank method - support the weight slightly with the crank, release the click, and crank the weight down controlled. Pull all cable off the drum. This gives you a clean start.

Inspect the cable for permanent deformation. If the brass cable has kinked or shows severe bends that won't straighten, replacement is necessary. Even after correct rewinding, permanently deformed cable will nest again quickly. Nylon rarely shows permanent deformation but should be checked.

Rewind the cable slowly by hand without connecting to the movement. Guide each wrap carefully ensuring it lays beside the previous wrap. Fill the drum completely in a single layer. After proper winding, test by cranking the weight up and down several times. The cable should remain organized through these test cycles. Only after successful testing should you reinstall the pulley and put the clock back in service.

Using the Crank Method

Safe Let-Down Procedure

The crank method allows rapid controlled weight descent without creating slack. Hold the winding crank in position. Use your free hand to lift the weight slightly, reducing tension on the click. Use your crank hand to release the click. Still supporting the weight with your other hand, slowly turn the crank backward allowing controlled descent.

This method prevents the sudden drop that creates slack and nesting. The weight descends smoothly under your control. The cable unwinds from the drum in organized fashion rather than tangling. The entire descent takes just seconds but provides control that prevents cable problems.

Practice the technique before using it on a fully-wound clock. The coordination between hands takes some practice. You need to support the weight, release the click, and control the crank simultaneously. Once mastered, the technique becomes natural. It's the proper method for any situation requiring rapid weight descent during service work.

Testing for Binding

Use the crank method to test for binding throughout the wind cycle. Wind the weight up and down slowly while feeling for resistance variations. Smooth operation throughout the cycle indicates proper cable installation. Notchy or binding spots indicate problems requiring investigation.

Binding typically occurs at specific drum positions rather than randomly throughout the cycle. The binding points correspond to where cable overlap exists. By identifying these positions, you can determine how severely nested the cable is. Multiple binding points indicate extensive nesting. A single binding point suggests localized overlap.

The sensitivity of feel testing exceeds visual observation. You can detect binding that's not visible externally. Small amounts of overlap create friction you can feel but can't necessarily see. This early detection allows correction before the nesting becomes severe enough to stop the clock during normal operation.

Full Cable Removal Test

When using the crank method, you can pull all cable off the drum for complete inspection. With the weight at floor level and cable fully extended, examine every inch of the cable. Look for kinks, wear, or damage. Check cable diameter consistency - manufacturing variations sometimes create thick spots that contribute to nesting.

With cable completely off the drum, inspect the drum grooves. Look for wear, burrs, or damage that could affect cable winding. Smooth any rough spots using fine files or emery cloth. The drum surface should be smooth with clean groove definition. Any imperfections will affect cable behavior.

This full inspection and cleaning provides fresh start for proper cable installation. You can't achieve reliable operation by half-measures. Complete cable removal, drum cleaning, and careful reinstallation produces results that last. Attempts to fix nesting without full removal usually fail within days or weeks.

Alternative Materials and Sources

Kevlar Cord Applications

Kevlar cord offers extremely high strength in small diameters. The material has no memory and doesn't stretch. It's easy to tie and holds knots reliably. These characteristics make it excellent for clock applications. However, Kevlar is difficult to cut and does flatten slightly under sustained load on drums.

For Seth Thomas #2 regulators, 200-250 pound test Kevlar provides appropriate diameter matching drum grooves. The higher test weights in Kevlar come in larger diameters. Match the diameter to your drum groove spacing rather than selecting based on strength rating. The strength far exceeds what clock weights require even in lower test ratings.

Kevlar costs more than nylon but lasts indefinitely. The material is extremely durable. It doesn't degrade from UV, chemicals, or abrasion. For clocks in challenging environments or for clockmakers wanting ultimate reliability, Kevlar justifies its higher cost. For typical residential clocks, nylon provides adequate performance at lower cost.

Radio Dial Cord

Traditional radio dial cord features a black braided cover over a non-stretchable core. Many Vienna regulator specialists prefer this material. The construction provides zero stretch with the core while the braided cover protects against wear. The material has proven reliability from decades of use in radio tuning mechanisms.

Radio dial cord is still available from specialty suppliers despite being obsolete for its original purpose. Search for vintage radio parts suppliers or clock-specific vendors. The availability is more limited than nylon cord but possible to source. The traditional appearance appeals to purists restoring clocks to original materials.

The diameter of available radio dial cord may not perfectly match Seth Thomas #2 drum grooves. Test fit before purchasing quantities. Some adjustment may be necessary either selecting slightly different drum or accepting less than perfect diameter match. The material's other advantages may outweigh diameter considerations for some applications.

Gut and Imitation Gut

Natural gut cord was original material for many antique weight-driven clocks, particularly English movements. Gut provides zero stretch with adequate strength for clock weights. However, gut degrades over time becoming brittle and weak. Replacement gut is expensive and still subject to deterioration.

Imitation gut made from synthetic materials attempts to provide gut's appearance without degradation problems. These materials work adequately for restoration work where original appearance matters. For functional reliability in clocks actually being used, modern nylon provides superior performance.

Seth Thomas #2 regulators originally used whatever materials were available and economical in their era. They were working timepieces, not museum pieces. Using modern materials that perform better doesn't compromise authenticity for most owners. Collectors restoring for exhibition may prefer period-correct materials despite functional compromises.

Preventive Measures

Owner Education

Educate clock owners about proper winding technique. Demonstrate slow steady winding maintaining tension throughout. Explain why rapid winding or partial winds cause problems. Most owners will follow guidance when they understand the reasons behind recommendations.

Provide written instructions with delivered clocks. Simple card explaining winding procedure prevents problems. Include warning about never letting partially wound weight drop suddenly. Many cable problems result from owner actions rather than installation defects. Prevention through education is more effective than repair.

Encourage owners to report any unusual resistance during winding immediately. Early-stage nesting creates minor resistance that's easy to correct. Severe nesting develops gradually if minor symptoms are ignored. Early intervention prevents major problems and protects the movement from stress and wear.

Regular Maintenance

Include cable inspection during routine servicing. Even properly installed cable can develop problems over years. Check for wear, fraying, or damage. Verify the cable still lays properly on the drum. Test by cranking the weight through the complete cycle feeling for binding or rough spots.

Brass cable in particular needs periodic replacement due to wear and memory development. Plan on replacing brass cable every 10-15 years even if it hasn't failed. Nylon lasts much longer but should still be inspected during major service. Prevention through scheduled replacement costs less than emergency repairs.

Clean the drum during servicing. Remove old oil and accumulated dirt from grooves. Polish any wear marks or rough spots. The drum surface condition affects cable behavior. Maintaining clean smooth grooves helps cable lay properly during winding. This simple maintenance step prevents many cable problems.

Documentation

Document cable specifications during installation. Record material type, diameter, and length. Note the supplier and part number. This information helps with future service. You or another clockmaker can reference this documentation rather than redetermining specifications.

Take photos showing proper cable installation. Document how the cable attaches to the drum and weight. Photograph the fully-wound drum showing proper single-layer cable placement. These references help identify problems during future service. They also prevent installation errors during subsequent cable replacement.

Keep records of any problems and solutions. If the clock develops nesting despite proper installation, note the circumstances. This information helps diagnose whether the problem is material selection, installation technique, or owner operation. Pattern recognition from documented cases improves your future installations.

FAQs

Why does my Seth Thomas #2 stop when the weight is one-third down?

Stopping at one-third descent indicates cable nesting on the drum. The cable has overlapped itself during winding creating tangled binding. As the weight pulls cable off the drum, the tangled section reaches the pulley and jams. This prevents further cable release stopping the clock despite adequate remaining drop distance. Check the drum - you'll see cable overlapping rather than laying in neat single-layer wraps. The problem develops gradually as cable memory causes progressive nesting. Correct by completely removing cable, inspecting drum grooves for damage, and rewinding carefully in single layer. Better solution is replacing stiff brass cable with flexible braided nylon that resists nesting. Prevent recurrence through proper winding technique maintaining tension without allowing slack.

What's the best cable diameter for Seth Thomas #2 regulators?

Calculate proper diameter from your drum groove spacing. Count grooves per inch on the drum. Divide one inch by groove count to get spacing. Cable diameter should be a few thousandths under this spacing. For typical Seth Thomas #2 drums with grooves, 3/64 inch (0.0469 inch) brass cable works, or 1.18mm (approximately 0.047 inch) solid-braid nylon. The diameter must fit groove spacing. Too-thick cable rides up groove sides and overlaps neighboring wraps causing nesting. Too-thin cable doesn't provide adequate drop distance in single layer. Measure your specific drum rather than assuming standard dimensions. Groove spacing varies slightly between movements. Test fit before cutting cable to length. The few minutes spent verifying diameter prevents hours troubleshooting nesting problems.

Should I use brass cable or braided nylon for my weight-driven regulator?

Braided nylon provides superior performance for most applications. Nylon is flexible and conforms naturally to drum grooves. It has no memory and doesn't tangle under normal conditions. Slight stretch absorbs shock during winding protecting movement components. Nylon lasts 60+ years without degradation. Brass cable looks more traditional but is very stiff and develops memory causing nesting. Brass requires perfect installation and meticulous winding technique. It damages drums and pulleys through concentrated wear. Many clockmakers who previously preferred brass have switched to nylon after experiencing reliability problems. Use 1.18mm solid-braid nylon (not hollow-braid). Sources include parachute cord suppliers selling micro-cord. For purists wanting traditional appearance, nylon in tan/coyote color approximates brass appearance while maintaining nylon's functional advantages.

How long should the weight cord be on a Seth Thomas #2?

Proper cord length allows weight to descend nearly to floor while leaving approximately one turn remaining on the drum. This prevents cable end pulling free while avoiding slack when weight reaches bottom. Typical Seth Thomas #2 regulators use approximately 41 inches of cord. However, cases vary in height. Measure your specific clock. Install the clock, attach weight, let it down until it nearly touches floor. Check how much cord remains on drum. Approximately one turn remaining indicates correct length. Multiple turns remaining means cord is too long - shorten it. No cord remaining with weight on floor means cord is too short - add length. Excessive length creates slack conditions guaranteeing nesting during next winding. Never let weight actually hit floor during operation - maintain slight tension even at lowest position.

How do I wind a weight-driven clock without causing cable to nest?

Wind slowly and smoothly maintaining tension throughout. Rapid cranking doesn't allow cable to settle properly causing bridging and gaps. Each wrap should lay beside the previous wrap without overlap. Keep slight backward pressure on crank as you wind preventing sudden weight drops that create slack. Never wind partially then release weight suddenly - this guarantees nesting. If you must stop winding partway, control weight descent carefully or complete winding fully. For brass cable, wind with the weight hanging to maintain tension. For any cable material, avoid situations creating slack during winding. Train new cable by winding and letting down 10-20 times before putting clock in service. This training removes cable memory and establishes proper drum pattern. The few minutes spent on careful winding technique prevents nesting problems requiring complete cable removal and reinstallation.

Can I fix cable nesting without removing the cable completely?

Temporary fixes rarely work long-term. You might untangle visible nesting and continue operation for a while, but the cable has learned the nested pattern. It will return to that configuration shortly. Proper correction requires complete cable removal. Use crank method to let weight down - support weight slightly with crank, release click, crank weight down controlled. Pull all cable off drum. Inspect cable for permanent deformation - kinked brass requires replacement. Inspect drum grooves for wear or damage. Rewind cable by hand in single layer ensuring each wrap lays beside previous wrap. Test by cranking weight up and down checking for binding. Only after successful testing should you return clock to service. The complete process takes 30-60 minutes but provides reliable long-term results. Half-measures fail within days or weeks requiring repeated service. Do it right once rather than repeatedly attempting inadequate fixes.

What's the crank method for letting weight down safely?

The crank method provides controlled weight descent preventing sudden drops that create cable slack. Hold the winding crank in position. Use your free hand to lift the weight slightly reducing tension on the click. Use your crank hand to release the click. While still supporting the weight with your other hand, slowly turn the crank backward controlling descent. The weight lowers smoothly under your control. Cable unwinds from drum in organized fashion. The entire descent takes just seconds. This technique prevents the sudden weight drop that creates slack and nesting. Practice the coordination before using on fully-wound clock. The method works for service situations requiring rapid weight descent. It also serves as test for binding - you can feel resistance variations throughout the wind cycle indicating cable problems. The sensitivity of feel testing exceeds visual observation for detecting early-stage nesting.