bitcoin seed phrase stamper M8

A cheap and easy solution to create fire proof, long lasting recovery phrases for your crypto wallet.

Inspired by the Blockmit-Jig. But with a clamp that prevents the washers from moving around while stamping.

I designed it in a way that you can assemble it with standard parts you can get from your local hardware store. You stamp your seed phrases on standard metric washers. 

I made it in two different sizes: This one uses the smaller M8 washers (M8.4x24x2). If you like to use the bigger M10 version, here is the link:

bitcoin phrase stamper M10 

In addition to the stamper you might also look for a good way to store your seed. Therefore i designed some tubes where you can put the washers in. Here is the link:

bitcoin phrase tube M8 

Stuff you will need:

A stamp set like this one:

Amazon Basics - Letter Punch Kit ~ 18€
(stamp size of the set i received from Amazon: 6.3 x 6.3 x 60 mm)

then the metal parts for the phrase stamper:

• 1x M10 nut (DIN934)
• 4x M3x20 bolts (DIN965)

Instructions

3D-Printing:

The gcode-files are sliced for a Prusa i3 MK3S.  There are two files, seperated by color. 

If you want to use the .3mf-files instead, print all the parts with standard settings. Works fine with PLA. No support needed. Just align the parts to the bed correctly.

Assembly:

The stamper jig consists of four parts: bottom, top, ring and the clamp. Take the clamp first, add some grease to the areas that have friction against each other. Then screw the clamp into the ring. Next you take to top part and align it with the ring and clamp. After that you can screw all parts with the M3x20 bolts together. Finally add the M14 nut to the bottom.

Stamping:

After you generated your seed phrase with you hardware wallet, stamp the letters into the washers. Lock the washer in place using the outer ring of the jig. Then take the guide and use the two notches for stamping the numbers and the other eight notches for the letters. 

And then finally keep everything at a safe place.