Updates

THE JOURNEY TO YOUR STōN-WOLF

8 Months of Building, Testing, and Learning the Hard Way

From STōN-3D founder Nathan, Prague, Czech Republic
 November 2025

 

 

To Our Customers

I'm not great at writing these kinds of updates. I'm better with a wrench than a keyboard. But you've been waiting, some of you for months, and you deserve to know what's actually going on.

We've shipped some machines—not all the first batch yet, but they're going out. Getting here was harder than I expected. A lot harder. I thought building the printer was the hard part. Turns out, that was the easy part.

This is everything that happened—the problems with suppliers, the certification stuff, the shipping nightmare. No marketing BS. Just what actually went down.

 

 

PART 1: THE DESIGN & BUILD (Months 1-3)

The Frame

I wanted 12mm thick CNC plates. Precision. Flatness. The kind that stays true.

The Outsourcing Problem:

The first external supplier was late. Then when parts arrived, quality was inconsistent. Out of spec on tolerances.

We tried outsourcing the CNC work to save time,and  increase scale.. Bad idea. Quality dropped. Every batch was a gamble—would they be flat enough? Would the holes align?

Worse: The feedback loop was terrible. Find a problem, send an email, wait for reply, explain the issue, wait for new parts. Weeks wasted.

The In-House Decision:

We decided to keep it “in-house”. My CNC machinist is like family to me and nearby. So although we don't own the shop, we try to support him as much as possible and consider it in-house. We share the related costs. The money-maker here = Martan (our CNC pro) + HAAS CNC machines. I didn't plan on our single HAAS handling production—seemed crazy. But quality was more important than speed.

Tight feedback loop: Send file, cut, inspect, ship. No emails. No waiting. No surprises.

Then our spindle bearing failed. Major failure. Machine down for a week or so.

Cost to fix: Around €4,000 and a lot of stress.

That pushed us over the edge—our machinist acquired a second HAAS to keep up and have backup.

Was it expensive? Yes.

Two HAAS machines, maintenance, tooling—not cheap.

But now we don't chase tolerances or wait for supplier excuses. We control quality.

Worth it.

The Flying Gantry Design

Our Cartesian design with the fixed bed—it's not common. Most people do CoreXY or bed-slinger.

Why fixed bed? Because when you're printing in the center of the bed (which is most of the time), the frame stays rigid. Shorter belts than CoreXY. Simple. But making my dream a reality meant new things to discover and solve. It was design deep. 

But we had to figure out belt routing and tension. Took a few tries to get the mounts right. The carbon fiber Y-gantry needed high-temp epoxy that wouldn't fail when things get hot.

It works now. But it wasn't plug-and-play like I hoped. Making a couple, and making a couple hundred is different. Expected, but always bites you anyway. 

The 48V Motion System 

We spec'd 48V motors for speed. High-quality from a reputable supplier.

Then the problems started:

  • First batch: Out of spec. Resonance issues at certain speeds.
  • Had to wait for replacements
  • Second batch: Late. Really late. Sometimes worse resonances
  • When they arrived: More tuning needed than expected

Total delay from motion system components: About 3 months and every batch must be tested.

We got it sorted. Then I opened a new box and things changed again. We denied them. But it was expensive and frustrating. Cost us over €15,000 in rejected parts and delays on that alone.

 

 

PART 2: ELECTRONICS (Months 3-5)

The Raspberry Pi CM5

I wanted the CM5 because it's the newest, fastest platform. Future-proof.

Problem: When pre-orders on the first batch closed, there was allocation issues—big companies got priority. We got our first 50 units months after I wanted them.Even thought hey showed stock. 

Had some mounting issues with our frame design—had to make a new CM5 cooler to avoid WiFi interference with the metal.

These are genuine UK-made Raspberry Pi CM5s. Not clones. But getting stock almost killed our timeline.

Controller Boards

We use BigTreeTech E3EZ boards, blowers and Filament sensors. They work well, but sourcing was a pain in the get-go. In the end we got a new sales agent and things improved drastically. , I met the owner (really nice guy btw) and gurus  like Luke.  Now we have a great relationship. They get back to me the same day. Ship faster than I do. Feedback is great and we are already seeing some product improvements based on feedback. 

Mean Well Power Supplies (and other small electrical parts) 

Mean Well is the gold standard. But getting all the certification documentation for customs was its own project.

Each PSU model has CE, UL, TÜV certifications. That's like 180 pages of documents per model. Our 24V and 48V models have different certification standards because of voltage class.

Spent weeks just organizing this stuff. But you need it—customs will hold your shipment without proper documentation.

 

 

PART 3: THE CERTIFICATION & SHIPPING REALITY (Months 4-8)

We Did Our Homework First

Before shipping anything, I prepared documents. Asked people in the field if everything looked legit. Component certifications, technical specs, compliance data.

I didn't want packages stuck in customs over a bad document.

So we hired an exporting company. They do this for a living. Figured they'd know better than me.

The Export Company Nightmare

Long sales calls. They said we were good to export. All set.

Then I asked: "What guarantee do I have that the documents are correct?"

They pushed it all back on me. "You're liable for the documents."

Which I get—it's my product. But that's why I paid them. To handle the legal stuff properly. That's what they sold me on. “We will handle all the docs and make sure it gets there”. I guess not. 

The Process (Or Lack Of One)

Submit documents. Wait days. No response.

Get automated email: "Pending."

Follow up calls: Another email saying "We got your request."

Progress was slow. Really slow.

When I went there in person:

Sat with an agent. Finally made some progress. But it felt like pulling teeth.

Spoke with management about the delays. They helped get a couple packages out after calls with the customers' local customs agencies.

The Real Work: Material Origins & EMC/RF Data

Filling in material origins for every component took forever. EMC/RF data for each electrical part. Compliance documentation.

If we did the classic "self-certify" thing—just claim compliance without real documentation—that would've been easy. Some shops do that.

But we're doing it right. Real certifications. Real documentation.

That takes time. More time than I expected.

Current Status

We've shipped some units. Not all dozen people have theirs yet—actually only a few so far.

But they're starting to trickle out. We're getting smoother at the process.

I push the export company daily. Things are moving now.

The "Kit" Solution

The export company uncertainty pushed us toward the kit approach.

Kit = user does final assembly (including electrical connections)
 Assembled = we're placing a finished product on market with full CE marking

Kit is legal. Gives us breathing room while we get full certification.

And honestly, our customers are makers—they want to build anyway.

Assembled Certification (The Long Road)

We're still getting assembled certification. It's already underway, but it's expensive and complicated. 

Testing Costs in EU:

  • EMC testing: €3,000-5,000
  • Safety/LVD testing: €2,000-4,000
  • Wireless/RF testing: €2,000-3,000
  • Re-testing when you fail: Another €3,000-8,000

Total cost for full certification: €5,000-10,000

For a small startup, that's significant.

Our Experience:

  • First round: Failed connector testing
  • The cables were from our supplier, but they didn't pass
  • Had to remake all cables ourselves
  • Re-test: €4,500
  • When we re-tested, they found new things to check
  • That's how it works—fix one thing, they test the next

We're through it now. Should have final certification soon.Until then we are good to go using the kit approach. 

Why It's Complicated

Different countries want different tests for "assembled CE" certification:

  • EMC (electromagnetic compatibility)
  • LVD (low voltage directive - safety)
  • Wireless/WiFi testing
  • RED (radio equipment directive)

Each test can fail on its own. Each failure costs time and money to fix and re-test.

Most small companies self-certify without all the testing. Some big companies do it properly—they can afford their own testing labs.

We're doing it properly. Just taking longer than I wanted.

Why The Raspberry Pi Makes This Complicated

The CM5 has WiFi built in. It's FCC and CE certified as a module.

But when you put it in a product with a metal frame, motors, and power supplies, that's a new system. Technically needs its own testing.

For kits: We can reference the CM5's certifications
 For assembled: We need full system testing

That's what we're doing now—getting it tested properly for assembled units.

 

 

PART 4: SOFTWARE & OPEN SOURCE

Stock Klipper

We use stock Klipper. 

Why? Because it's what the community knows. Open source (GPL v3). And the input shaping is perfect for our high-speed setup.

We spent a lot of time tuning configs for our system—pressure advance, input shaping, all that. But it's standard Klipper underneath. But for many people setting up a printer and using SSH to write code is not acceptable. We aimed to avoid that. Here we are. 

Open Source: Already Started

GitHub is live: https://github.com/STON-PRINTERS

We've already started releasing files:

  • Wolf repository: CAD files for the printer - CC-BY-SA-4.0 license
  • Wifi-config repository: Our Rust-based WiFi setup tool - GPL-3.0 license

Choosing the Right Licenses (Not As Simple As It Sounds)

Picking open source licenses took time. Had to get legal feedback to make sure I wasn't making a dumb decision.

For hardware (CAD files): CC-BY-SA-4.0

  • Creative Commons Attribution-ShareAlike
  • You can use, modify, sell our designs
  • Must give credit
  • Must share improvements under same license
  • Standard for open hardware

For software (WiFi tool, configs): GPL-3.0

  • GNU General Public License v3
  • You can use, modify, distribute
  • Must share source code
  • Must use same license for derivatives
  • Standard for open source software like Klipper

Overall pretty easy once I understood the options. But worth getting it right.

The "ston-builder" WiFi Tool (4-5 Months Extra)

We wrote a WiFi setup tool in Rust. It's called "ston-builder."

What it does: Makes WiFi setup for Klipper printers super easy. No SSH, no command line editing config files. Just works.

Why it matters: The entire Klipper community can use it. Not just STōN printers—ANY Klipper setup. GPL-3.0 licensed, completely open. Just Scan a QR code, which will link to the machine /network. (Re-name it with a cool static IP address if you wish.) Then scan another QR to take you to mainsail. Print. Sounds easy right….?  Not so much. 

The problem: Took 4-5 months longer than expected.

Most of that was debugging and network testing in real print conditions. WiFi is finicky—different routers, different networks, interference, dropped connections.

Had to test it in actual print environments, not just on a bench. That takes time.

But it works now. And it's available for everyone.

Why Open Source Matters

We use Klipper (open source). We use Linux (open source). Seems wrong to keep our stuff closed.

So we're releasing everything:

  • CAD files (CC-BY-SA-4.0)
  • Software tools (GPL-3.0)
  • Klipper configs (GPL-3.0)
  • Documentation (open)

Community can modify, improve, share. That's the point.

 

 

PART 5: INTERNATIONAL SHIPPING (The Complex Part)

This is where things get really complicated. Shipping a 20kg printer plus 8kg packaging (28kg total) with electronics and WiFi across borders? There's a lot of rules.

HS Codes (The Foundation)

Every product has an HS code—Harmonized System code. It's a global standard for classifying goods.

For 3D Printers: We use HS Code 8477.80.90.90  (at the time of publishing this update)- "Machinery for working rubber or plastics - Other"

Why this matters:

  • Determines duty rates (3.1% for USA)
  • Tells customs what regulations apply
  • Affects documentation requirements

EU Shipping (Simpler)

Within EU:

  • No customs duties (we're Czech-based)
  • VAT already included
  • 3-7 day delivery
  • No additional costs for customer

Pretty straightforward since we're all in the EU.

USA Shipping (Complicated)

This is where it gets expensive for customers.

The $800 Rule:

  • Shipments under $800 landed value: Duty-free
  • Our kit with shipping: Over that threshold
  • So duty applies

What USA Customers Should Expect to Pay:

  • 3.1% duty on full value: varies by final calculation
  • Customs processing fees: varies by carrier and location
  • Total additional: approximately $100-200 range

These are estimates based on typical shipments. The exact amount can vary based on:

  • Your local delivery area fees
  • How customs calculates the landed value
  • Which carrier handles final delivery
  • Current fee schedules

We'll give you our best estimate before shipping, but we can't guarantee the exact final amount since some fees are determined on your end.

Customers Already Paid Shipping: You paid for shipping when you ordered. If carrier costs went up on our end (they did), we absorb that. Not your problem.

Why We Can't Fake The Value: That's customs fraud. Seriously illegal. Could lose the business, face criminal charges. Not worth it to save $30.

We declare true value. Always.

Shipping Carrier: DHL

We use DHL Express for most shipments.

Why?

  • Fast (3-5 days)
  • Professional customs handling
  • Lower damage rate
  • Real tracking

The Pricing Reality:

Customers paid for shipping upfront based on quotes. But DHL kept adding fees and raising rates on us after the fact.

That's our problem, not the customer's. We absorb those extra costs.

Is it expensive for us? Yes. A 28kg package internationally isn't cheap, and the rates kept climbing.

But customers already paid what we quoted. We honor that.

Other Countries

Canada: 0% duty (USMCA), but GST/PST applies (~5-15%)
 UK: 3.1% duty + 20% VAT (Brexit made this harder)
 Australia: 5% duty + 10% GST

Each country has different rules. We provide documentation, but customer handles customs clearance.

 

 

PART 6: SUPPLIER CHALLENGES & THE REAL COSTS

The Reality of Sourcing

Getting quality parts from multiple countries isn't as smooth as ordering on Amazon.

Major Supplier Problems:

Motion System Components:

  • First batch: Out of spec, resonance problems
  • Return and reorder: 6 weeks
  • Second batch: Late by 8 weeks
  • Additional tuning: 4 weeks
  • Total delay: ~3 months
  • Cost: €15,000 in rejected parts and rework

Heater Supplier:

  • Promised: 6 weeks
  • Actual delivery: 4 months late
  • Impact: Couldn't complete any printers for months
  • Had partially assembled units sitting in warehouse
  • Cost: Warehouse time, delayed revenue, opportunity cost

Raspberry Pi CM5:

  • Launch delays from Raspberry Pi Foundation
  • Large companies got allocation priority
  • We waited in queue for months
  • Finally got stock, but 3-4 months behind schedule
  • Had to redesign mounting due to WiFi interference with frame

Component Lead Times (Reality vs Promise):

  • Mean Well PSUs: Quoted 2 weeks → actual 6 weeks
  • Motion components: Quoted 3 weeks → actual 12+ weeks (with problems)
  • Linear rails: Had to reorder once (spec error on my end)
  • Heaters: Quoted 6 weeks → actual 4 months
  • CM5: Expected at launch → actual 3-4 months

Quality Control & Rejected Parts

We test everything before it goes in a printer:

  • Frame plates: Flatness within tolerance
  • Linear rails: Smoothness and preload
  • Power supplies: Voltage regulation
  • Motors: Resistance and resonance
  • Heaters: Temperature accuracy

Rejection rate: Around 5-8% depending on component

That's parts we paid for but can't use. Every rejection means:

  • Waiting 4-8 weeks for replacement
  • Paying for the replacement
  • Delayed customer orders

The Real Cost of "Learning"

Over 8 months of development, dealing with:

  • NOK (not okay) parts we had to scrap
  • Late suppliers causing delays
  • Hiring people who then left (training cost, restart cost)
  • Design iterations and prototypes
  • Testing and re-testing

We spent over €100,000 on what I'll call "tuition fees"—the cost of learning how to do this right.

Breakdown:

Rejected/NOK components: ~€35,000

  • Design iterations and prototypes: ~€25,000
  • Hiring and training people who left: ~€20,000
  • Failed first-round certifications: ~€8,000
  • Warehouse costs during delays: ~€7,000
  • Unexpected shipping and customs issues: ~€5,000

That's money that doesn't show up in a finished printer. That's just the cost of figuring this out.

But We Planned for This

Here's the thing: I knew it wouldn't be smooth. Saved up all my pennies before launch. 

I didn't know exactly what would go wrong, but I knew something would. So we budgeted extra time and money for problems.

We planned for the storm:

  • Built in financial buffer (good thing)
  • Expected supplier delays (still worse than expected, but planned for it)
  • Kept pushing through problems instead of giving up
  • Didn't ship bad parts just to hit a deadline

We're late. But we're still here. And the machines work.

 

 

PART 7: WHAT I LEARNED (AND HOW WE SURVIVED)

Mistakes I Made

Underestimating Lead Times: I thought suppliers meant what they said. "3 weeks" actually meant 6-8 weeks. Sometimes 12 weeks. Sometimes 4 months.

But I budgeted extra time anyway. Good thing.

Thinking Kit Would Be Simpler: Selling as kit solves some regulatory problems. But creates others:

  • Documentation takes forever
  • Customer support is different (helping with assembly)
  • Still need detailed instructions

It's not easier, just different challenges.

Promising Dates Too Early: Told people "March shipping." Actually shipped September-November.

Should've said "Q3" or "when ready."

Next time: No specific months until units are already shipping.

Not Expecting Everything to Break: Motion components out of spec. Heaters 4 months late. CM5 backordered. Cables failing certification.

But here's what I did right: I expected problems.

How We Survived: Planning for the Storm

Financial Buffer: I didn't spend all the money immediately. Kept reserves for when things went wrong.

Good thing—because we burned through €100,000+ on problems.

Timeline Buffer: I told myself the worst case = "6 months to first shipment" but planned for 12 months internally.

We shipped at 8 months. Late to customers, but within my internal worst-case.

Refusing to Cut Corners: When the motion components came in out of spec, I could've:

  • Shipped them anyway (customers wouldn't know immediately)
  • Used cheaper alternatives
  • Blamed the supplier

Instead: Sent them back. Waited. Paid for replacements. Cost €15,000 and 3 months.

But the printers work right.

Staying Stubborn: When the heater supplier was 4 months late, I had partially built printers sitting. But the heater supplier needed that time to make sure the heater was acceptable. I don't want to place blame, just speak about delays to give a context of time. I will order from them again. Just budget more time. 

Could've given up. Could've tried to get refunds and find another supplier.

Instead: Waited. Pushed the supplier. Kept going.

What Went Right

No Compromises on Quality: Genuine Raspberry Pi CM5. Mean Well PSUs. Quality motion components. Connectors, filters, CNC frame.

We didn't cheap out. That was correct.

The Design Works: Wolf prints fast and accurately. 48V motion delivers. CPAP cooling is effective.

The machine is good. 

First Units Are Printing: The units we've shipped—people are printing with them. Getting positive feedback often for the testers also. 

Not everyone has theirs yet (only a few so far), but the ones out there are working. That makes the struggle worth it.

We're Still Here: 8 months. Lots of money in problems. Multiple supplier failures. Certification failures.

Still shipping. Still building. Still improving.

That's the win—we didn't quit.

 

 

PART 8: WHERE WE ARE NOW

Current Status (November 2025)

What's Shipped: First dozen machines are out. People are starting printing with them. The others slowly leave the exporter. The documents per country don't need to be done all over again. But most of those dozen were spread around. Hence the delay. 

Component Stock: For the first time in months, we actually have components in stock:

  • CM5 modules: Good supply now
  • Mean Well PSUs: Stocked
  • Controller boards: Sufficient
  • Frame plates: Ready
  • Rails and bearings: On hand

Assembly: Getting faster. First units took 7-8 hours to build. Now down to about 2-3 hours per machine.

Quality control is better. Rejection rate improving.

Shipping Timeline

EU Customers:

  • Order to ship: depends on order number
  • Delivery: 3-7 days
  • Additional costs: None (VAT included)

USA Customers:

  • Order to ship: depends on order number
  • Delivery: 3-5 days (DHL)
  • Additional costs: approximately $100-200 (duty and customs fees - estimates, varies by location)
  • We'll provide our best estimate before shipping
  • Note: You already paid shipping when you ordered. If carrier rates went up, we absorb that.

Other Countries:

  • Varies by location
  • We provide cost estimate upfront
  • Customer handles customs

Assembled Certification

Still in process. Testing is expensive—$3,000-5,000 per round.

We failed connector testing first time. Remade cables, re-tested. Looks good now.

Once fully certified for assembled units, we can:

  • Ship as complete printers (not just kits)
  • Sell to businesses for government work
  • Have proper CE marking on the entire unit. 

Target: Early-2026 for full certification

Open Source - Already Live

GitHub is active now: https://github.com/STON-PRINTERS

Currently available:

  • Wolf repository: CAD files for the printer
  • Wifi-config repository: Rust-based WiFi setup tool for Klipper

More documentation and files being added regularly.

 

 

PART 9: QUESTIONS PEOPLE ASK

Q: Why not just get full FCC/CE certification now?

A: $3,000-5,000 per round of testing. 8-12 weeks each time. As a small startup, I had to choose: Ship kits now to early customers, or wait months and burn through cash for certifications before any revenue.

We're doing the certification now. It's in process. But it's expensive and takes time.

Q: Can you lower the customs value so I pay less duty?

A: No. That's customs fraud. Could lose my business, face criminal charges. Not worth it to save $30.

I declare true value. Every time.

Q: Why is USA shipping so expensive for me?

A: Combination of:

  • Shipping a 28kg package internationally
  • 3.1% import duty
  • Customs processing fees

The duty and customs fees vary by your location and how customs calculates everything. We give you an estimate upfront (approximately $100-200 range).

Note: If shipping carriers raised rates on us after you paid, we absorb that. You paid what we quoted.

Q: Will you tell me the exact cost before shipping?

A: We'll give you our best estimate based on typical shipments. But we can't guarantee the exact final amount since some fees (like local delivery or how customs calculates landed value) are determined on your end. The estimate should be close though.

Q: When will the GitHub files be available?

A: They're already available at https://github.com/STON-PRINTERS

We've released CAD files and our Rust WiFi setup tool. More documentation and files being added as we finish them.

Q: Can I buy just parts?

A: Not yet. Once production is stable (December 2025), we'll offer spare parts separately.

Q: What's the warranty?

A: 1 year on electronics, 2 years on mechanical (EU law). We'll support you beyond that, but I'm a small operation so can't promise forever. We stick to the component manufacturer's warranty. 

 

 

PART 10: FINAL THOUGHTS

If You Already Ordered

You're getting your printer. Taking longer than originally promised, but it's coming.

Everything we said you'd get—genuine CM5, quality motion components, CNC frame, name-brand parts—that's what you're getting.

About shipping: You paid for shipping when you ordered. If carrier costs went up on our end (they did—DHL kept raising rates), we absorb that. Not your problem.

If you're in the USA, we'll email you an estimate of the customs costs before we ship (approximately $100-200 additional). The exact final amount might vary slightly based on local fees, but our estimate should be close. 

If You're Thinking About Ordering

What you're getting:

  • Premium components (we didn't cheap out)
  • Unique flying gantry design
  • Fast print speeds (300-600mm/sec realistic)
  • Built one-by-one in Prague
  • Maker-friendly (stock Klipper,  open source)

What you should know:

  • It's a kit (3-5 hours assembly)
  • International shipping costs extra (non-EU)
  • Small company (But that's a good thing for performance machines)
  • Still figuring some things out

What I promise:

  • Real parts, no substitutions
  • Honest communication (like this document)
  • Support when you need help
  • Open source

Why I'm Sharing All This

Look, I'm not great at marketing. I'm better at building machines.

But I figure if I'm asking people to trust me with their money, they deserve to know what's actually going on. The delays, the problems, the costs, all of it.

We started to ship machines. They work. People are printing with them. That's the goal—to get more of them out there.

If you have questions, email me. I'll answer.

Thanks for reading this long thing.

 

 

Nathan D. 

STōN-3D
 Prague, Czech Republic

Contact:
 nathan@ston-3d.com
 ston-3d.com

Built in CZ, shipped worldwide (with complications)

 


 November 15, 2025