Leather wallet manufacturing is a highly precise craft.
A standard bifold wallet is usually made of around 12 individual leather components, and even a 0.1 mm dimensional deviation in a single part can significantly affect thickness, folding balance, and daily usability.
This is why sewing and skiving accuracy are critical in bifold wallet OEM production.
The 6-Step Sewing Workflow for Bifold Wallet Manufacturing
1. Pattern Development
Design patterns for approximately 12 components.
Special attention is given to height and width tolerances, especially around the bill compartment opening, to ensure smooth insertion and removal of banknotes.
2. Cutting
Outer leather, lining, reinforcement, and interlining are cut with high precision.
Consistent cutting accuracy forms the foundation for thickness control in mass production.
3. Skiving
Each component is skived to an ultra-thin tolerance.
This step is especially critical for 4-card-slot structures, where excessive thickness quickly accumulates.
4. Sewing
The interior, exterior shell, and bill dividers are stitched together.
Controlled step differences are formed intentionally to maintain clean folding lines.
5. Assembly
Card slots are aligned in parallel, coin pockets are attached, and folding symmetry is tested.
6. Finishing
Final thickness adjustment, edge inspection, and repeated open-close tests are performed to ensure durability and smooth operation.
The most challenging aspects of this process are dimensional tolerance management and skiving consistency.
Even minor 0.1 mm errors, when accumulated, can push the wallet beyond acceptable thickness standards.
Diamond Chisel & Waxed Thread Techniques
The accuracy of diamond chisel punching directly determines the lifespan of a hand-stitched wallet.
Stitch Pitch Options
Diamond chisel pitch typically ranges from 1.5 mm to 5.0 mm.
4.0 mm pitch is recommended for beginners and standard OEM work.
It offers a good balance between visual density and workload.
3.0 mm pitch creates finer, more refined stitching, but significantly increases punching time.
5.0 mm pitch produces a bold, rugged appearance and shortens production time.
Recommended Diamond Chisel Configuration
2-tooth diamond chisel (4.0 mm pitch)
Used as the main tool. Excellent for curves, easy guideline alignment, and efficient force transfer.
4-tooth diamond chisel (4.0 mm pitch)
Best for straight sections, allowing faster hole punching.
With these two tools, most small leather goods can be completed efficiently.
Practical Hole-Punching Methods
Standard Method
Use a wooden or plastic mallet to punch holes directly through the leather.
Silent Precision Method
Lightly press the diamond chisel to mark positions, then open each hole individually with an awl.
This method is quieter, produces cleaner holes, and allows precise hole-size control.
Waxed Thread Selection Criteria
Linen thread
Requires waxing. Wax reduces fraying and increases tensile strength.
Nylon / Polyester thread
Does not require waxing. Naturally smooth, high strength, and consistent.
Sinew thread follows the same principle.
Matching Thread Thickness to Stitch Pitch
5.0 mm pitch pairs best with 0.8 mm–1.2 mm thread.
When using thread thicker than 1.2 mm, holes must be widened with an awl if necessary.
- On thick leather, thread tends to sink into the hole, making visible stitch length shorter.
- Thread choice significantly impacts stitch appearance, even when hole size remains unchanged.
Flatbed Sewing Machines & Edge Skiving Techniques
The flatbed sewing machine is the most widely used equipment in leather goods OEM factories.
It supports leather thickness from 0.6 mm to 1.2 mm, covering card slots, interiors, and exterior shells.
Flatbed Sewing Machine Setup
Thin leather (0.6 mm) to thicker leather (1.2 mm) can be sewn by adjusting needle size and thread.
- For card-slot stitching, presser foot pressure must be reduced to prevent leather compression.
Proper pressure control largely determines the final visual quality.
- Flatbed vs. Lockstitch Machines
Flatbed machines excel at flat structures, such as layered card slots.
Lockstitch machines are used for three-dimensional structures.
OEM factories typically operate both to maximize efficiency.
- Essential Edge Skiving Knowledge
Where Step Skiving Is Required
Fold-back edges must be step-skived to 0.3–0.4 mm thickness.
With a core thickness of about 1 mm, this range provides optimal balance.
Correct skiving:
Improves stitch consistency
- Creates uniform edge folding
- Reduces thread snagging by up to 95%
- Skiving Machine Setup
Common machines include NIPPY, NOPRO, TAKING TK801/802.
Standard round blade width is 30–35 mm, ideal for consistent edge skiving.
Spacer adjustments are made in 1 mm increments, typically 12–18 mm
Acrylic plates with paper shims are sometimes used for micro-adjustments
- Efficiency Techniques in OEM Mass Production
Fixed Skiving Thickness Strategy
By fixing skiving thickness at 0.3–0.4 mm, flatbed sewing can be standardized.
This minimizes setup changes and significantly improves productivity.
Corner Radius Jigs
The Kikuyose-kun® PRO jig (Patent No. 7226870) is commonly used.
Standard radii: 10 mm, 15 mm, 20 mm
Example:
- 13 mm design → use 10 mm jig
- 17 mm design → use 15 mm jig
- Adjustable slit range: 12–18 mm
The PRO version features increased plate thickness for durability in long-term mass production.
Stitching Method Comparison
Hand Stitching vs Flatbed Sewing vs Lockstitch Machines
When selecting a sewing method for bifold wallet OEM, three factors matter most Durability, Appearance, and Efficiency Durability Comparison
Hand Stitching
Single-thread structure. Even if one section breaks, the stitch does not unravel.
Durability retention exceeds 95%, making it ideal for premium wallets.
Machine Stitching
Upper and lower threads interlock, creating strong fixation.
However, thick threads cause compression deformation, increasing deformation by 20–30%.
Lockstitch (JIS 301) offers twice the fixing strength of hand stitching, ideal for mass production.
Aesthetic Differences
Hand-Stitched Diamond Holes
Hole consistency rate: 98%
- Reduced seam wrinkling
- Superior edge finishing and longer-lasting edge gloss
- Recommended stitch spacing: 5–7 mm
Edge roundness retention exceeds 90%
Flatbed Sewing Limitations
Uniform on straight lines
- Hole distortion occurs on thicker leather
- Visual quality drops 10–15%
- Continuous needle holes roughen edges
- Lockstitch Characteristics
Symmetrical front and back appearance
- Higher fixation strength
- Slight hole expansion due to looper capture in JIS 301 process
- Production Efficiency Data
Hand stitching: 30–60 minutes per meter
Flatbed sewing: 1–2 minutes per meter
Lockstitch machines: Up to 10× faster than hand stitching, hundreds of meters per day
Thickness Limits by Stitching Method
MethodPractical Thickness LimitHand Stitching8–10 mm (up to 12 mm with edge skiving)Flatbed Sewing6–8 mm (up to +2 mm with skiving)Lockstitch MachineUp to 10 mm (up to +3 mm with skiving)
Conclusion
Over the past 15 years, I have seen countless custom wallet projects.
One truth remains consistent:
There is no single “perfect” stitching method for leather wallets.
What matters is selecting the technique that best matches your brand’s priorities
Whether it’s the warmth of hand stitching or the stability of machine sewing, each method has its place.
If this guide helps you better understand bifold wallet OEM manufacturing, then it has achieved its purpose.
Let’s continue creating leather products that are built to last.