Table of Contents
Why you need this BlockMIT Jig
Your Bitcoin seed phrase is the only thing standing between you and permanent loss. Paper burns at 451°F. Floods destroy it. House fires happen. If your seed phrase is on paper or in a digital file, it’s one disaster away from gone forever.
The Blockmit jig makes it easy to stamp your seed phrase into standard metal washers — the kind that survive house fires, floods, and 50+ years of storage. No special skills, no expensive tools, no excuses.
This is the simplest fireproof Bitcoin backup solution available. At $4.99, there’s no reason not to.
What you need to get started
The Blockmit jig is the alignment tool. You’ll also need:
- Metal washers — 24mm OD (outer diameter). Get them on Amazon here
- Letter/number punch set — 1/8″ (3mm) size. Get the punch set here
- Hammer — any steel hammer, 1-2 lbs
- Hard surface — concrete floor, anvil, or steel plate
That’s it. Total setup cost under $30. Protects a lifetime of Bitcoin.
Need the washers in 1-inch size instead? Check out our CC 1-inch Washer Jig — fits standard US hardware store washers.
24mm vs 1 inch — which do I need?
| Jig | Washer Size | Where to Buy Washers | Best For |
|---|---|---|---|
| Blockmit Jig (this one) | 24mm OD | Amazon (link above) | Original Blockmit spec, slightly smaller form factor |
| CC 1-inch Jig | 1 inch OD | Any hardware store in the US | Easier to source washers locally, 16 alignment spots |
Both work. The Blockmit jig is the original format. The CC jig uses washers you can buy at Home Depot today.
What’s included
- 2x Blockmit washer jigs
- Two jigs included in case one gets damaged during stamping
- Punch set and washers NOT included — see links above
Shipped from Colorado. Bitcoin accepted.
How it works
- Place a 24mm washer into the jig slot
- Position your letter punch on the first marking spot
- Strike firmly with a hammer
- Advance to the next spot, repeat for each letter of your seed word
- One washer per seed word — 12 or 24 washers for a complete backup
- Store in a fireproof safe, safety deposit box, or buried steel container
Full visual guide: DIY Seed Phrase Backup Tutorial — Estudio Bitcoin
Why buy from CryptoCloaks
- Bitcoin-native — we use what we sell. Self-custody is core to everything we do.
- Ships from Colorado — next business day, no overseas wait
- Bitcoin accepted — pay in sats
- 25 reviews at 4.88 stars — real Bitcoiners, real results
- 2 jigs for $4.99 — one for the job, one backup in case of a missed strike
Also check out our Seedor Safe seed storage for an engraved stainless steel alternative — no stamping required.
FAQ
Does the Blockmit jig come with washers?
No. Washers and punch set are sold separately. You need 24mm OD metal washers and a 1/8″ (3mm) letter punch set. Links above.
Is this fireproof?
The jig itself is 3D printed plastic — not fireproof. But the washers you stamp are steel, which is fireproof. The jig is just the alignment tool. Your finished backup washers are what survives a fire.
How many washers do I need?
One washer per seed word. A 12-word seed = 12 washers. A 24-word seed = 24 washers.
What punch size do I need?
1/8″ (3mm). This is the size that fits the Blockmit jig slots correctly.
What’s the difference between the Blockmit jig and the CC 1-inch jig?
The Blockmit jig uses 24mm washers (order online). The CC 1-inch jig uses standard 1-inch washers available at any US hardware store. The CC jig also has 16 alignment spots vs the original format.
Does CryptoCloaks accept Bitcoin?
Yes. Bitcoin native. Pay in sats.
What are the exact dimensions?
See pictures below.









Russell W. (verified owner) –
Very simple and easy to use. Maybe less slack in movement of entire ‘dial’ and punch hole would be better if possible to manufacture that way.
Bryan (verified owner) –
Very nice quality! Got two in a nice little box.
Michael Rutherford (verified owner) –
Received item as ordered. Thanks
Jim B. (verified owner) –
Great value and speedy delivery…what more could you ask for? Can’t wait to put it to use.
Anonymous (verified owner) –
Incredible product with great packaging presentation
Travis (verified owner) –
Awesome product for an amazing price!
Rick F. (verified owner) –
Impressed with the mindful packaging and quality of the two 3-D printed jigs I purchased. Good service and for the use I intend for them at a fair price. Thank you Rick V. All the best for life in Loveland, CO from the Pacific NW.
Anonymous (verified owner) –
Great quality, fast shipping!
Michael S. (verified owner) –
Great little gadget for us OCD folks. Fast service!
Mark (verified owner) –
Very fast and responsive