When you order a CoinConnex case or SlabGrid tray from StoneFyr, you are getting a product that went through a specific process before it reached you. This is what that process looks like, from the initial idea to the package on your doorstep.
Every product starts with a problem worth solving. For CoinConnex, the problem was clear: collectors were storing graded slabs in containers not designed for them, and their coins were paying the price. Cardboard boxes, tackle boxes, and generic plastic containers all share the same flaw. None of them were built for the actual dimensions of NGC, PCGS, CAC, and ANACS holders.
We do not design products because they would be cool to make. We design them because someone has a problem that existing products do not solve well enough. That filter keeps our catalog focused and our products genuinely useful.
Before any design work begins, we gather data. For coin storage, that meant buying slabs from every major grading service and measuring them with digital calipers. Not one of each, but many, from different years and denominations, because manufacturing tolerances vary between batches and the design has to accommodate the full range.
We also research how collectors actually use their storage. Forum posts, Reddit threads, coin show conversations. Real-world use reveals requirements that armchair design misses. How do people transport their coins? How do they browse their collection? How do they add new acquisitions? Those behaviors drive design decisions.
All design happens in Fusion 360 using parametric modeling. Every dimension is a variable: slab width, slab thickness, wall thickness, clearance, lid engagement depth. If any measurement changes, the model updates automatically. This is how we build a family of products (5, 10, 15, and 20-slab cases) from a single base design.
The first design is never right. It is a starting point, a best guess based on measurements and mechanical intuition. The real design happens in the next phase.
We print the first prototype and immediately test it with real slabs. Does the fit work? Is the lid smooth? Does the stacking mechanism engage properly? Usually the answer to at least one of those is "not quite."
So we iterate. Adjust a clearance by 0.15mm. Deepen a track by 0.3mm. Widen a relief by 0.2mm. Print again. Test again. A new product typically goes through 8–15 prototype iterations before the design is locked. Each iteration takes 1–3 hours to print, so we can cycle through several versions in a single day.
Injection molding cannot do this. Each mold change costs thousands of dollars and takes weeks. With 3D printing, a prototype iteration costs a few dollars in filament and a couple hours of machine time.
Once the design is finalized, we dial in the production print settings. Layer height, print speed, nozzle temperature, bed temperature, infill density, wall count, and cooling all affect the final product. We print test batches and measure the output to make sure production dimensions match the validated prototype.
We also lock in the material. Every production storage and display product prints in PETG for its strength, heat resistance, and long-term dimensional stability. PLA keeps its place earlier in the process, on prototypes, where print speed matters more than durability. The material follows how the product will be used, not what is easiest to print.
Production runs are tracked in our inventory system with batch numbers, quantities, filament usage, and quality notes. Each run is assigned to a specific printer with calibrated settings, and we monitor prints during production, because a failed print at hour three of a four-hour run wastes material and machine time.
Our printers run Bambu Studio sliced files with validated profiles. Print settings are version-controlled so we can reproduce any batch exactly. If a customer reports an issue with a specific product, we can trace it back to the exact production run and printer.
Every unit is inspected before it enters inventory. We check dimensional accuracy (spot-checking with calipers), surface quality (visual inspection for layer defects, stringing, or under-extrusion), and mechanical function (the lid slides smoothly, the stacking locks engage, slabs fit correctly).
Parts that do not pass inspection are recycled. We do not sell seconds or B-stock. If it does not meet the standard, it does not ship.
Products are packed to prevent damage in transit. Lightweight rigid parts can crack if crushed, so the packaging includes appropriate padding. Orders are fulfilled from our workshop and shipped via USPS or UPS depending on size and destination.
From idea to your door, a new product takes two to four months to develop and validate. Once it is in production, your order is printed, inspected, packed, and shipped within days. That is the advantage of manufacturing in-house: no overseas lead times, and no inventory sitting in a warehouse for months.