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SKU:GKA-3639SP-GD-4L
PRODUCT DESCRIPTION
Designed for precise bass tuning, stable performance, and modern lightweight hardware upgrades. These locking bass tuning machines feature a 1:26 gear ratio, CNC-machined aluminum alloy body, and brass gears for compatible bass guitar replacement and custom build projects.
Key Features
- Locking bass tuner design: Helps secure the string at the post for improved tuning stability and easier string changes on compatible bass guitars.
- 1:26 gear ratio: Provides fine tuning control for accurate bass tuning adjustments.
- CNC-machined aluminum alloy body: Offers a lightweight and durable tuner housing for modern bass hardware upgrades.
- Brass gear construction: Supports smooth tuning operation and reliable mechanical performance.
- Multiple layout options: Available in 4L, 4R, 2R+2L, 1L, and 1R layouts for different bass headstock configurations.
- Fitment reminder: Please confirm your bass guitar’s tuner dimensions, M13 × 1 thread requirement, string post height, mounting screw position, and tuner layout before ordering.
Technical Specifications
| SKU / Model | GKA-3639SP |
| Product Type | Bass Tuning Machines |
| Tuner Type | Locking Bass Tuning Machines |
| Suitable For | Bass Guitar |
| Gear Ratio | 1:26 |
| Structure | Locking |
| Body Material | CNC-Machined Aluminum Alloy |
| Gear Material | Brass |
| Overall Length | 87.3 mm |
| String Post Height | 24.6 mm |
| Thread Size | M13 × 1 |
| Color / Finish Options | Chrome, Black, Gold, Green, Red |
| Layout Options | 4L, 4R, 2R+2L, 1L, 1R |
| Package Includes | Varies by selected layout option |
| Weight | approx. 73.1 g per tuning machine |
Compatibility Notes
Important: Please confirm your bass guitar’s tuner hole, M13 × 1 thread requirement, 24.6 mm string post height, mounting screw position, and tuner layout before ordering. Bass headstock designs may vary by model, production year, factory, and region.
Package Includes
- Package quantity varies depending on the selected layout option.
- 4L option: 4 x 1L bass tuning machines, 4 x bushings, mounting screws
- 4R option: 4 x 1R bass tuning machines, 4 x bushings, mounting screws
- 2R+2L option: 2 x 1R bass tuning machines, 2 x 1L bass tuning machines, 4 x bushings, mounting screws
- 1L option: 1 x 1L bass tuning machine, 1 x bushing, mounting screws
- 1R option: 1 x 1R bass tuning machine, 1 x bushing, mounting screws
Installation Note
Before installation: Compare the tuner layout, M13 × 1 thread size, 24.6 mm string post height, overall dimensions, and mounting screw position with your original bass tuning machines to confirm compatibility.
VIDEO
FAQS
Do you class a reverse headstock guitar as a left hand guitar?
How do I determine the right size/fit for a specific accessory?
Can you provide more details about the materials used in your products?
At Guyker, we prioritize the use of high-quality materials to ensure the durability and performance of our products. While the specific materials used may vary depending on the accessory, we commonly utilize materials such as:
■ Metals: We often use materials like stainless steel, aluminum, and brass for hardware, bridges, and other metal components.
■ Plastics: Certain accessories may incorporate durable and impact-resistant plastics such as ABS or polycarbonate for knobs, pickguards, and other components.
■ Woods: Some accessories, like guitar knobs or picks, may be made from various types of wood, including rosewood, ebony, or maple.
For more detailed information about the materials used in a specific product, we recommend reviewing the product descriptions or reaching out to our customer support team at [support@guyker.com] for further clarification.
Do you offer international shipping?
Yes, we offer international shipping to customers worldwide. When placing your order, please ensure that you provide accurate international shipping information, including your complete address and contact details.
Please note that international shipping may be subject to customs duties, taxes, and additional fees imposed by the destination country. These charges are the responsibility of the recipient and may vary depending on the country's customs policies.
What is your process for returning or exchanging a product?
To initiate a return or exchange, please follow these steps:
■ Contact our customer support team at [support@guyker.com] or visit our website's Returns/Exchanges page.
■ Provide your order details and the reason for the return or exchange.
■ Our customer support team will guide you through the process and provide you with a return/exchange authorization if applicable.
■ Follow the instructions provided, including packaging the product securely and attaching the necessary labels or documentation.
■ Ship the product back to us using a traceable and insured shipping method.
■ Once we receive the returned product and verify its condition, we will process the return or exchange accordingly.
Can I return or exchange a product if it's been used?
In most cases, products that have been used or show signs of wear may not be eligible for return or exchange unless there is a defect or error on our part. We recommend reviewing our specific return/exchange policy or contacting our customer support team at [support@guyker.com] to determine the eligibility of your particular product.
Do I need to cover the return shipping costs?
The responsibility for return shipping costs may vary depending on the reason for the return or exchange. In some cases, such as if the product is defective or if we made an error, we will provide a prepaid shipping label or reimburse your return shipping costs. However, if the return or exchange is due to a change of mind or a non-defective product, you may be responsible for the return shipping costs. We recommend reviewing our return/exchange policy or contacting our customer support team at [support@guyker.com] for specific details regarding return shipping costs.

Guyker GKA-3639SP Locking Bass Tuning Machine 1:26 Ratio with CNC Aluminum Alloy Body
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