The Happy Hacking Keyboard has a new wintery home.

An aftermarket upgrade kit for the HHKB Pro 3

This is a special limited-edition holiday 2021 offering, made in frosted polycarbonate with a textured white rear cover plate. It also happens to be the last batch of Heavy Grails that will ever have been produced. Manufacturing is already complete on the housings themselves, so when these sell out, they're gone for good.

Reviews and praise for the original Heavy Grail (currently sold out, but with some extras anticipated in early 2022)

"...a massive feat of engineering and a spectacle to behold..."
—Material Journal

"It far exceeds my expectations!! I am so impressed by how high level everything is: the box, the product credential folio, the grail itself, all the little parts gathered together. ... The Heavy Grail is a homerun!"
—Official HHKB Evangelist @dhoboy

"As ever, the product and packaging are unmatched. Immaculate."
—@jblanton on Twitter

"I am in love with it."
—Ral on Keebtalk

"probably the most premium feeling kit I've had the pleasure of laying my hands on"
—winbear.builds on IG

"The piece that elevates this board to the unequivocal pinnacle of my collection (with no exaggeration) is the nearly obsessive extent to which Ryan invokes the HHKB typing experience with this case’s acoustics and flexibility."
—bongounicorns on Keebtalk 

"Ooh lala. It sounds perfect and is a great weight. ... How could I not love it?"
—Olivia (of GMK Olivia and Olivia++)

This is a limited pre-order. Manufacturing of the housings is complete, but we are still waiting on retail boxes and some small hardware components, which aren't due to arrive for a month or more (thanks to persistent disruptions at the ports here in Los Angeles). Units ordered today are expected to be assembled and ship the week of 08/07.

Note: All crystal polycarbonate switch plate units have been allocated at this point with possible extras to come.

Background

My job is to take the most beloved keyboards in the world and design their dream homes: housings that upgrade humble stock injection-molded encasements into meticulously crafted, CNC-machined art objects.

I've been at this for nearly 8 years, and whenever I go to keyboard meetups, speak at events, or otherwise interact with my fellow typing nerds, I've gotten one question more than any other: when will I offer a case for the venerable HHKB? It has seemed an almost insurmountable technical challenge, but the Heavy Grail is its ultimate answer.

At every step in the process of its creation, I've chosen the pursuit of perfection over cost or expediency, because there is no point investing so much into solving one of the hardest problems in the keyboard world and not doing it properly. The result is a quixotic exercise in lavish keyboard overkill—but that, of course, is just as I would have it.

Custom injection-molded, hand-polished switch plate

The most difficult part of making an HHKB housing is that, unlike all other Topre keyboards, its stock plate is integrated with its stock housing; they're a single piece of plastic. The HHKB switch plate thus can't simply be transplanted into one of my housings like the switch plate for others of my aftermarket housings.

This has meant my needing to re-create an entirely new plate from scratch with all the features of the original, minus the surrounding thin-walled housing. The only hitch is that the original part is one of the most intricate, fussy, hyper-engineered, and complex single-piece injection-molded parts I've ever seen. And when it comes to the feel of using a keyboard, my tests show that measurements off by even 0.1mm can perceptibly alter the feel and sound of a switch mechanism.

The geometry of my switch plates includes "slider housings" with mating surfaces that the HHKB sliders rub against during each keystroke. I have insisted that these be as smooth as physically possible to provide the optimal tactile and acoustic experience. In order to achieve this, I've had to work closely with the makers of the steel injection tooling (here in the USA) to create a special complex mold with 120 removable inserts that allow us to get deep inside the recesses of these slider housings to meticulously hand-polish each mating surface up to an uber-smooth mirror finish. Not only was this stupid expensive; developing this plate took literally years.

Extra switch plates are available separately here. (currently sold out, but likely some extras in early 2021.)

Comprehensively engineered acoustic system

Each Heavy Grail comes with a gasket system die-cut from vibration-dampening Poron. This soft upper gasket forms a full seal around the switch plate, which helps to simulate that soft bouncy feel that is characteristic of the original HHKB's injection-molded housing while also limited external sound transmission.

Sound transmission and internal reflections are further mitigated by a natural merino wool felt dampener affixed to the rear cover plate.

This kit for the ultimate HHKB build requires a bit of DIY assembly.

This is a kit for serious keyboard enthusiasts. While the build isn't difficult, it does require taking apart your HHKB and a bit of patience to transplant some parts from one plate into the other. The following video walks you through the process in full detail.

Arcane technical notes

Compatibility This version of the Heavy Grail is designed to support HHKB Pro 3 Classic series (the current, USB-C form sold by Topre/Fujitsu). Note that the Pro 3 version of the Heavy Grail can also technically house a PCB from a "Pro 3 Hybrid" HHKB in addition to the "Classic" models, but with slightly reduced functionality (see next section below). 

Pro 3 Hybrid models If you venture to use a "Pro 3 Hybrid" model with a Heavy Grail, you'll lose the battery functionality—unless you undertake some serious DIY modding, as some clients have— but the bluetooth should still work if you attach a powered USB cable. (The use case here is if you use your HHKB to switch typing inputs among multiple devices.) This isn't per se an offically supported scenario, but hobbyists who have experimented with this usage report that it's feasible and works well. YMMV.

Use without gasket You can use the Grail without the isolation mount gasket, as the white-plate product image shows, but your keycaps will sit slightly higher (just over 1mm) relative to the housing face.

Silencing rings If you use silencing rings with the Heavy Grail, your keycaps will sit slightly lower than normal (by the same amount as your rings are thick), unless you're using the purple sliders that have extended length to offset for silencing rings.

Dip switches The dip switches on on the Pro 3 model are accessible through the rear cover plate, as shown below. (However, the Ghost of Christmas Future Edition housings will all have a white rear cover plate rather than the black one shown below.)