Fray racing, a unique and demanding form of slot car competition, pushes the limits of vintage pancake motor cars. Success in Fray racing hinges not only on driving skill but also on meticulous car preparation. At the heart of this preparation lies the selection and skillful application of specialized Fray Slot Car Tools. This guide will walk you through the essential steps to transform a classic ThunderJet chassis into a Fray-ready machine, highlighting the specific tools and techniques that can elevate your performance on the track. We’ll focus on modifying the iconic T-Jet chassis, a favorite among Fray enthusiasts, ensuring it’s primed for victory within Fray regulations.
Step 1: Disassembly & Initial Inspection
Before any modifications can begin, a thorough disassembly of your ThunderJet chassis is crucial. This process allows for cleaning, inspection, and targeted improvements. Carefully take apart the chassis, separating the gear plate, armature, magnets, and pickups. Pay close attention to the condition of each component. Look for wear and tear, especially on gears and brushes. This initial assessment will guide your tuning strategy and identify parts that may need replacement or special attention.
Alt text: Two vintage ThunderJet slot car chassis ready for Fray modification, showcasing a Hot Rod and Dune Buggy model.
Step 2: Ultrasonic Cleaning
Once disassembled, a deep clean is essential. An ultrasonic cleaner is an invaluable fray slot car tool for this step. These devices use ultrasonic waves to agitate a cleaning solution, reaching into every nook and cranny to remove dirt, old lubricant, and debris that can hinder performance. For a cleaning solution, options like ammonia-based cleaners, Simple Green, or Pine-Sol work effectively. Submerge the chassis components (excluding the armature if you are concerned about moisture in the windings) in your chosen solution and run the ultrasonic cleaner for approximately 15 minutes to ensure everything is thoroughly cleaned.
Alt text: Slot car components submerged in an ultrasonic cleaner, a fray slot car tool, for thorough cleaning and preparation.
Step 3: Rivet Tightening
After cleaning and drying, reassemble the chassis loosely. A critical step in preparing a Fray car is tightening the rivets that hold the chassis plates together. Loose rivets can lead to unwanted movement and inconsistent gear mesh during racing. Specialized fray slot car tools are available for this task. The SCM Performance Blue Print kit, created by Charlie O. in Kansas City, includes a rivet tightening tool, among others vital for T-Jet work. Kevin Crowe of Winning Edge also offers a similar tool. Alternatively, a nail set from a standard tool kit can also be used carefully. The goal is to tighten the rivets just enough to eliminate play without over-tightening and potentially binding the chassis.
Alt text: Using a rivet tightening tool from the SCM Performance Blue Print kit, a specialized fray slot car tool, to secure the chassis plates.
Step 4: Armature Hole Reaming
To minimize friction in the drivetrain, consider reaming the armature hole in the gear plate. This process slightly enlarges the hole, reducing contact between the armature shaft and the gear plate. While this modification might be deemed illegal under certain rule sets like VHORS, it can be a beneficial tweak for Fray racing where rules are often less restrictive on such modifications. A .068 reamer from Wizzard High Performance is the recommended fray slot car tool for this task. Ream the hole carefully, ensuring it remains concentric to avoid introducing wobble.
Alt text: Enlarging the armature hole with a .068 reamer from Wizzard High Performance, a fray slot car tool for friction reduction.
Step 5: Pinion Gear Removal
Removing the armature pinion gear is necessary for several subsequent modifications, including armature balancing and gear adjustments. A gear puller is an essential fray slot car tool for this step. The Winning Edge gear puller is a popular and effective choice for T-Jet pinions. Using the gear puller prevents damage to the armature and gear during removal. Position the puller carefully, ensuring it grips the pinion securely and then gently press the pinion off the armature shaft.
Alt text: Employing the Winning Edge gear puller, a fray slot car tool, to safely remove the armature pinion gear.
Step 6: Driven Gear and Shaft Removal
Further disassembly involves removing the driven gear and cluster gear shaft. Again, the SCM Blue Print kit offers specialized fray slot car tools to facilitate this process. These tools are designed to safely and effectively remove these components without causing damage. Using these tools, carefully extract the driven gear and shaft from the gear plate. This step is crucial for cleaning, gear repositioning, and other performance enhancements.
Alt text: Utilizing tools from the SCM Blue Print kit, essential fray slot car tools, to dismantle the driven gear assembly.
Step 7: Gear Plate Rail Removal
Fray rules often permit the complete removal of the rails on the gear plate, a modification that can lower the car’s body and center of gravity. However, be aware that other racing organizations like VHORS and UFHORA may have stricter rules regarding rail removal. To remove the rails, carefully use an X-acto blade. This process requires patience and a steady hand to avoid damaging the gear plate. Ensure you retain the portion of the gear plate where the chassis clamp sits, as this is still required under Fray rules.
Alt text: Carefully removing gear plate rails with an X-acto blade, a common fray slot car modification technique, while preserving the clamp area.
Step 8: Gear Plate Finishing
After removing the rails, the gear plate should look clean and functional. Ensure that you have not cut into the section below the plane of the gear plate and that the patent number remains intact. This detail maintains some of the original character while optimizing for Fray racing.
Alt text: Modified gear plate with rails removed, a fray slot car chassis preparation step, ensuring the patent number remains untouched.
Step 9: Gear Polishing
Reducing friction in the gear train is paramount for maximizing speed. Foam-backed emery boards, commonly found in dollar stores for fingernail care, are surprisingly effective fray slot car tools for polishing gears. These boards come in various grits, allowing you to progressively polish the gear teeth to a smooth finish. Gently sand the gears, removing any molding imperfections or roughness.
Alt text: Polishing slot car gears using foam-backed emery boards, affordable fray slot car tools, to enhance smoothness and reduce friction.
Step 10: Cluster Gear Shaft Cleaning
Inspect the cluster gear shaft for any buildup or corrosion. If the shaft is crudded up, as often seen in older chassis, cleaning is necessary. While replacement is an option, you can restore the original shaft using a Dremel rotary tool. Chuck the shaft in one Dremel and use another Dremel equipped with a wire brush to carefully clean and polish the shaft.
Alt text: Cleaning a cluster gear shaft with a Dremel and wire brush, fray slot car tools for restoring and maintaining original parts.
Step 11: Driven Pinion Gear Repositioning
Another technique to reduce friction is to reposition the driven pinion gear lower on the cluster gear shaft. Using the gear puller again, gently move the driven pinion gear further down the shaft. Note that cutting the cluster gear shaft or using aftermarket shafts like JW’s titanium shafts might not be legal under Fray rules, so repositioning is a Fray-legal alternative to minimize friction.
Alt text: Repositioning the driven pinion gear lower on the shaft with a gear puller, a fray slot car tuning method to minimize chassis friction.
Step 12: Driven Gear Attachment
Reattaching the driven gear to the cluster gear shaft requires precision. The SCM Blue Print kit provides fray slot car tools for this, often used in conjunction with a feeler gauge. A .005″ feeler gauge, with a small section cut out to accommodate the shaft, is ideal for setting the correct gear clearance. Place the feeler gauge between the gear plate and driven gear, then gently tap the gear onto the shaft until it makes contact with the feeler gauge. A small portion of the shaft will typically protrude above the driven gear, which is acceptable.
Alt text: Attaching the driven gear to the cluster gear shaft using tools from the SCM Blue Print kit and a .005 feeler gauge, fray slot car tools for precise assembly.
Step 13: Armature Shaft Cleaning
Similar to the cluster gear shaft, the armature shaft can also benefit from cleaning. Chuck the armature in a Minimite Dremel or similar holder, and use another Dremel with a wire brush to remove any crud or oxidation from the shaft. This ensures smooth rotation and optimal performance.
Alt text: Cleaning the armature shaft with a Dremel and wire brush, fray slot car tools for preparing the armature for optimal performance.
Step 14: Armature Stack Truing (Poor Man’s Lathe)
To minimize the air gap between the armature and magnets, a technique called armature stack truing can be employed. This involves reducing the diameter of the armature stack. A “Poor Man’s Lathe” setup, using two Dremel tools, can be used for this. Mount the armature in one Dremel and use another Dremel with a diamond cutting wheel from Harbor Freight to carefully true the stack. This method, while effective, was initially developed due to Fray rules allowing magnet sanding to reduce air gap. Be cautious and remove material gradually to avoid damaging the armature.
Alt text: Truing the armature stack using a ‘Poor Man’s Lathe’ technique with Dremels and a diamond cutting wheel, fray slot car tools for armature optimization.
Step 15: Armature Balancing
Armature balancing is a crucial step for high-speed Fray racing, although it is not permitted in VHORS rules. An unbalanced armature can cause vibrations and limit RPM. A watchmaker’s poising tool is a precision fray slot car tool designed for balancing small rotating components like slot car armatures. Alternatively, the razor blade technique can be used. Spin the armature in the poising tool and identify the heavy side. Use a Dremel to carefully remove material from the heavier side until the armature spins smoothly without significant vibration. Balancing can also be achieved by adding epoxy to the lighter side, although removing weight is often preferred to maximize RPM. Professional armature balancing services are also available from experts like Ron Hershman, Alan Galinko, and Mike Briggs.
Alt text: Balancing a slot car armature with a watchmaker’s poising tool, a precision fray slot car tool, to reduce vibration and increase RPM.
Step 16: Pinion Gear Pressing
With the armature balanced, it’s time to reinstall the pinion gear. JW’s press is a specialized fray slot car tool designed for accurately pressing pinion gears onto T-Jet armatures. This press ensures the gear is seated squarely and at the correct depth on the shaft, preventing misalignment and gear mesh issues.
Alt text: Using JW’s press, a fray slot car tool, to accurately install the pinion gear onto the balanced armature.
Step 17: Gear Height Adjustment
Even with a press, fine-tuning the pinion gear height is often necessary. Re-employing the SCM Blue Print Kit and a .005″ feeler gauge, adjust the pinion gear on the armature shaft to achieve the optimal .005″ clearance. This precise adjustment ensures smooth and efficient gear mesh, minimizing friction and maximizing power transfer.
Alt text: Adjusting the pinion gear height with the SCM Blue Print Kit and a .005 feeler gauge, fray slot car tools for achieving optimal gear mesh.
Step 18: Assembled Gear Plate
With all gear modifications complete, the gear plate is reassembled, now housing a balanced and trued armature, modified gears, and optimized clearances. This refined gear plate is a significant step towards a high-performance Fray slot car.
Alt text: Completed gear plate assembly with balanced armature, trued stack, cut rails, repositioned pinion, and optimized gear clearances, showcasing Fray slot car modifications.
Step 19: Magnet Matching
Matching magnets for strength is important, although less critical with Johnny Lightning (JL) magnets compared to older Aurora magnets, as JL magnets are generally more consistent. BRP’s Magnet Matcher is a fray slot car tool designed to measure magnet strength, allowing you to select a matched pair for your chassis. While JL magnets exhibit better consistency, using a matcher can still help identify the strongest and most closely matched pairs in your stock.
Alt text: Matching Johnny Lightning magnets using brp’s Magnet Matcher, a fray slot car tool for selecting magnets with consistent strength.
Step 20: Magnet Sanding
JL magnets are larger than Aurora magnets, and Fray rules permit sanding them to fit certain chassis. VHORS and UFHORA rules have restrictions on magnet sanding. Sanding the face of the magnet, in particular, can improve fit and reduce air gap, enhancing motor performance. Use the diamond cutting wheel and foam emery boards to carefully sand the magnets. Aim for a thickness around .253″, which is often the Fray limit. Use calipers to monitor your progress and avoid over-sanding.
Alt text: Sanding Johnny Lightning magnets to reduce size for better chassis fit, a fray slot car tuning technique using a diamond cutting wheel and emery boards.
Step 21: Magnet Size Check
To ensure compliance with Fray rules, which often specify a maximum magnet width, use digital calipers to check the magnet size after sanding. The Fray limit is often .700″ between the magnets. Rick Terry of RT Racing and Kevin Crowe of Winning Edge both produce .700″ plugs specifically for checking magnet spacing. These plugs, along with calipers, are essential fray slot car tools for ensuring your car meets regulations.
Alt text: Verifying magnet size with digital calipers and a .700 plug, fray slot car tools for ensuring compliance with Fray racing regulations.
Step 22: Idler Gear Sanding
Just like the main gears, the idler gear can benefit from polishing to reduce friction. Use the foam-backed emery boards to gently polish the idler gear. Be extremely careful not to over-sand, as this can chamfer the gear teeth, which is not permitted. The goal is simply to polish the gear surfaces, not reshape them.
Alt text: Polishing idler gears on a foam board, a fray slot car technique to reduce friction, while being careful not to chamfer the gear edges.
Step 23: Gear Tooth Cleaning (Wire Brush)
For a quick and effective way to clean gear teeth and remove any remaining roughness, use a wire brush. This method acts similarly to using polishing compounds like Simichrome or Brasso but is faster and less messy. Briefly brush the gear teeth to achieve a cleaner, smoother surface, further minimizing friction in the gear train.
Alt text: Cleaning gear teeth with a wire brush, a quick fray slot car method to remove roughness and improve gear mesh.
Step 24: Brush Conditioning
Wizzard brushes are frequently favored for their performance. Before installation, it’s beneficial to condition new brushes. Rub the brushes lightly on the fine section of a foam emery board. This removes any tiny ridge or burr on the edge of the brush, which some believe can negatively impact commutator contact.
Alt text: Conditioning Wizzard slot car brushes on a fine emery board, a fray slot car practice to optimize brush contact and performance.
Step 25: Brush Trek X
To control brush rotation and potentially enhance motor performance, apply a “Trek X” or a single line of conductive paint to the brushes. This modification, named after Trek Lawler, is now legal under Fray rules. This technique can influence brush dynamics and improve electrical contact with the commutator.
Alt text: Applying ‘Trek X’ to slot car brushes, a fray slot car modification to control brush rotation and enhance motor performance.
Step 26: Pickup Spring Replacement and Pickup Restriction
Stock pickup springs are often inadequate for Fray racing. Replacing them with stiffer BSRT pickup springs is a common upgrade. Additionally, using thinner BSRT 504 pickups allows for a lower front end. AML (American Line) pickup shoes are another option. To further improve handling, restrict pickup travel. Using needle-nose pliers, carefully fold the top of the pickup hanger forward, towards the front of the car. Restrict travel just enough so the pickup shoe sits level with the bottom of the tires when extended. This keeps the pickups firmly on the rails, preventing chassis hop and improving power delivery.
Alt text: Replacing pickup springs with BSRT springs and restricting pickup travel, fray slot car modifications to improve track contact and handling.
Step 27: Axles and Crown Gears
Upgrading to oversized axles is highly recommended for Fray cars. BRP oversize drill blank axles, with a .0635″ diameter, eliminate slop in the rear end and improve handling. Drill blanks or reamer blanks are preferred axle materials. Use Loctite green or red to securely glue the crown gear to the axle. For routed tracks, consider using the smaller diameter AFX Specialty crown gear with Wizzard plastic spacers. While still a 15-tooth gear, its smaller diameter allows for smaller rear tires, beneficial on smoother routed surfaces. Aurora guidepins, glued in place, are typically used, with AML guidepins also being legal, but Nu-Rora guidepins are not permitted in some Fray rule sets.
Alt text: Setting up axles and crown gears for Fray racing, utilizing brp drill blank axles and AFX Specialty crown gears, key components in fray slot car chassis assembly.
Step 28: Front Tires
For front tires, O-rings from RC car shocks mounted on Wizzard FR54A brass wheels are a popular choice. To meet the Fray minimum front tire height of .300″, a strip of electrical tape can be wrapped under the O-ring to increase the diameter. RC car shock rebuild kits offer O-rings in various colors, while black O-rings are readily available at most hardware stores.
Alt text: Installing o-ring front tires on brass wheels, a fray slot car tire setup, using electrical tape to achieve the minimum .300-inch height.
Step 29: Front Tire Height Check
Always verify the front tire height to ensure it meets the Fray minimum of .300″. This ensures compliance with regulations and proper car stance on the track.
Alt text: Verifying front tire height at the .300-inch Fray racing minimum, ensuring compliance with regulations.
Step 30: Rear Tires
For routed tracks, .316″ Dunlop silicone sponge tires are an excellent choice. Use a Lucky Bobs wheel press, a specialized fray slot car tool, to mount these tires evenly and securely onto the rear wheels.
Alt text: Mounting Dunlop silicone sponge rear tires using a Lucky Bobs wheel press, a fray slot car tool for precise tire installation.
Step 31: Tire Adjustment
After mounting rear tires, adjust the overall tire width to meet the Fray 1 5/16″ maximum limit. A tire puller can be used to fine-tune the tire position on the wheels, ensuring compliance and optimal track performance.
Alt text: Adjusting rear tire width to the 1 5/16-inch Fray racing limit, ensuring optimal track performance.
Step 32: Pickup Alignment Check
Proper pickup alignment is critical for consistent power delivery. Use a section of track with the rail exposed underneath to check pickup alignment. Ensure the contact portion of the pickup shoe lies flat and makes full contact with the rail.
Alt text: Checking pickup alignment on a section of track, a fray slot car setup step to ensure consistent power delivery.
Step 33: Light Front End Setup
A light front end setup, often achieved by omitting wheel spacers, is common in Fray racing. With the Fray minimum weight now at 20 grams, you may need to add weight elsewhere to meet this requirement if using a lightweight body. Experiment with and without front wheel spacers to find the optimal setup for your car and body combination.
Alt text: Light front end setup for a Fray slot car chassis, prepared to meet the 20-gram minimum weight requirement.
Conclusion
Building a competitive Fray slot car requires a combination of skillful assembly, precise modifications, and the right fray slot car tools. By following these steps and utilizing the recommended tools and techniques, you can transform a standard ThunderJet chassis into a high-performing machine ready to tackle the challenges of Fray racing. Remember to break in your newly built chassis and experiment with fine-tuning to unlock its full potential on the track. The world of Fray racing blends nostalgia with cutting-edge tuning, offering a rewarding experience for those who appreciate the art and science of slot car modification.
