First, I’d like to apologize to the community for my clumsy entrance — I probably came across like a drunk guy stumbling into a party he doesn’t yet understand. I should have spent more time learning the community norms first.
That said, let me try to respond to your very insightful and constructive questions.
At this scale, water tends to replace the air film and introduce surface tension and capillary forces between the ball and raceway. That adds drag rather than reducing friction, especially when combined with fine particles or residue. So your concern is absolutely valid.
Our honest answer is that we’re constantly balancing real-world usability against technical constraints. We did consider applying hydrophobic coatings to the raceway, but in practice those coatings wear off very quickly at the actual contact points inside the bearing, which makes them ineffective over time.
Instead, we focused on making the internal structural components corrosion-resistant and water-tolerant, and designed the system so that, rather than trying to completely block water from entering, it can be easily cleaned and quickly dried.
The “sticky” or sluggish feel water introduces in a micro-bearing is temporary. In practice, you can restore normal performance by blowing it dry with a hair dryer in about a minute.
The analogy we often use is washing your hair: if you’re not in a hurry, it will air-dry on its own. If you need to go to sleep right away, you use a hair dryer. In either case, the impact on the overall experience is minimal.
By the way give me a bit of time — I promise I’ll put together a more systematic report with photos and data from our testing. There’s no real secret sauce here, just a lot of trial, error, and tiny tolerances.
A few repost are ok, https://news.ycombinator.com/newsfaq.html but after a few (whatever that mean) repost people start to get angry. Specially if it's your own project and specialty if it's commercial.
Usually more technical post get better traction, so if you have some interesting side quest building the device, it may be better. But it must be interesting. What is your favorite anecdote about building the device to tell to your fiends over a beer? (Bonus points if it's a technical friend.)
Some ideas from https://www.youtube.com/@Clickspring . But the guy is extremely good so it's a very high bar, it's not necessary to be as good as this guy to post here. (Anyway, I prefer a blog post with photos than a video.)
If you have two accounts, you can ask hn@ycombinator.com about how to merge them, or perhaps they will tell you to just use one of them and never use the other again.
To be honest, I’m not trying to hold back on technical details. At its core, this is simply an integrated bearing structure, so the overall concept itself is quite straightforward.
What we’ve been more cautious about sharing at this stage are the manufacturing and process details, since the project is still in its early phase. I understand that this can sometimes come across as being less transparent, and that’s a fair concern.
One example that genuinely surprised us during testing was that laser engraving caused slight deformation, which affected how smoothly the ring could spin. Because of that, we decided to move to a different engraving method to preserve performance.
Either way, I truly appreciate the feedback and suggestions. Until I’ve properly edited my “beer story,” I’ll take a step back from posting here for now.
Thanks again for taking the time to engage and share your perspective.
> What we’ve been more cautious about sharing at this stage are the manufacturing and process details, since the project is still in its early phase. I understand that this can sometimes come across as being less transparent, and that’s a fair concern.
It's not necessary to tell all the details, everyone has a secret sauce. Also some details are boring. Other details change too much.
> One example that genuinely surprised us during testing was that laser engraving caused slight deformation, which affected how smoothly the ring could spin. Because of that, we decided to move to a different engraving method to preserve performance.
That's very interesting! Ensure to add it. Can you rectify the ring after the laser engraving? Is the engraving customized and it is the last step?
We originally planned to use electro-etching to put the Spinity logo on every ring by default. In hindsight, that wasn’t a great idea for a brand that’s just being born.
One user even joked that when the ring spins, “spinity” sometimes reads like “stupid” — which was a very fair reminder that branding should earn its place, not demand it.
So we took the community’s advice and removed the default logo entirely. The outer surface is now intentionally left blank, which also aligns better with our minimalist design philosophy. Engraving is only done when someone explicitly requests customization.
That’s why, process-wise, engraving is always the very last step. If something goes wrong there, the part becomes scrap — which is painful, but it’s the only way we’ve found to preserve predictable spin performance in such a thin system.
In the public demo images, we also deliberately hide what we consider our main structural innovation: the internal ball-loading port on the inner ring. The opening is just slightly larger than the bearing balls (around 1.3 mm), and that detail is what allows us to compress the total ring thickness down to about 2 mm.
One of my favorite moments was a user telling us they had tried to 3D-print a bearing ring themselves and couldn’t get it to work — which makes sense. At this scale, additive manufacturing just doesn’t hit the tolerances needed for consistent motion.
Thanks for pushing me to be more open. I’m still learning how to balance protecting early-stage process details with showing genuine respect for a technically-minded community like HN.
Lol, Thanks! This small engineering upgrade ended up delivering a surprisingly huge improvement. The mass-production version will be priced under $100 — the precision is too high for stamping, so every part has to be CNC-machined. That makes it slightly more expensive than typical spinning rings, but in terms of smoothness and spin performance, there is literally no spinning ring on the market that can compete.
One problem I see is, people may not want to wait 20 seconds for a dice roll.
There is also the nostalgia of a D20. Just keep in mind that this will be a novelty and not a replacement. Unless people still D&D in steam tunnels and such?
Great point. It actually spins at about 10 rotations per second, so you can lightly stop it after 2–3 seconds and still get a perfectly random result.
That said, some tabletop players raised another concern — in group play, someone could cheat by spinning it again after seeing the result. And that’s a fair point.
But the ring is primarily designed as jewelry and a fidget piece. At only 2 mm thick, comfort and aesthetics come first.
As a D20 tool, it’s best suited for solo TTRPG sessions where there's no dispute, and it works wonderfully in that context.
So I completely agree it’s not a replacement for a traditional D20. It’s more of a D&D-themed accessory that happens to be functional in certain situations,Thank you so much!
Thanks for the feedback! I’m pretty new to posting on HN, so the writing style might be a bit rough — still figuring out the “right amount of em-dashes”
As for the video, it plays fine on my side, but it might be restricted by Vimeo’s region or Cloudflare settings on your network. I’ll double-check the permissions to make sure everyone can view it. Thanks for the heads up!
It’s essentially a 2mm-thick micro-bearing in the shape of a ring, so anything getting inside would be a serious issue.
The good news is that after sealing, the only opening is a 0.1mm side gap between the inner and outer rings — and in normal daily wear, nothing gets through.
(I’ve worn it for 3 months with no buildup.)
Extreme cases like mud or beach sand are possible. In those situations, a gentle spin under running water should clear it out.
I only wanted to leave an external reference on this very old platform — it now lives on the About page, and that’s enough for me.
And as for customers: we don’t really welcome people who feel overly self-important.
That said, let me try to respond to your very insightful and constructive questions.
At this scale, water tends to replace the air film and introduce surface tension and capillary forces between the ball and raceway. That adds drag rather than reducing friction, especially when combined with fine particles or residue. So your concern is absolutely valid.
Our honest answer is that we’re constantly balancing real-world usability against technical constraints. We did consider applying hydrophobic coatings to the raceway, but in practice those coatings wear off very quickly at the actual contact points inside the bearing, which makes them ineffective over time.
Instead, we focused on making the internal structural components corrosion-resistant and water-tolerant, and designed the system so that, rather than trying to completely block water from entering, it can be easily cleaned and quickly dried.
The “sticky” or sluggish feel water introduces in a micro-bearing is temporary. In practice, you can restore normal performance by blowing it dry with a hair dryer in about a minute.
The analogy we often use is washing your hair: if you’re not in a hurry, it will air-dry on its own. If you need to go to sleep right away, you use a hair dryer. In either case, the impact on the overall experience is minimal.
By the way give me a bit of time — I promise I’ll put together a more systematic report with photos and data from our testing. There’s no real secret sauce here, just a lot of trial, error, and tiny tolerances.