the Heavy Grail

The Heavy Grail is an aftermarket upgrade kit for the HHKB Pro 3 Classic keyboard from Topre/Fujitsu. It includes a CNC-machined housing and custom injection-molded switch plate.

The Heavy Grail story

I've been at the business of making aftermarket keyboard housings for nearly eight 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 I am happy to say that I now have an answer to that recurring question: today.

At every step in the process of its creation, I've chosen the pursuit of perfection over cost or expediency, because there's no sense 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.

It has, happily, been very well received by the keyboard community.

Critical acclaim

Technical background

Custom injection-molded, hand-polished switch plate

Made in the USA.

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 plastic 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 radically alter the feel and sound of a switch mechanism.

The geometry of the Norbauer HHKB switch plate (included with each Heavy Grail) 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.

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 and limits external sound transmission from the interior chamber of the housing.

External sound transmission and internal sound reflections are further mitigated by a natural merino wool felt dampener that rests on the rear cover plate.

Complex compound geometry that can only be milled on a 5-axis mill

People who have followed the inspiration and philosophy behind my designs know that I'm particularly keen on midcentury-style retro-futurist shapes, and in particular housings that have my trademark taper along the side. However, combining that taper, a rounded edge, and an inherent slope angle means that the Heavy Grail can't be cut on a conventional 3-axis CNC mill. Instead, a much more costly milling machine (and and much more complex CAM program) must be used to for the process that carves the housing out of a solid block of metal. This roughly doubles the milling cost compared to a traditional 3-axis housing like the Norbaforce.

Customizable aesthetics

Material and finish options to suit your workspace and personal style.

Year-of-the-Dragon Edition. Aluminum plated with a vibrant red finish. Rear cover plate is stainless steel in a textured white powder coat. White switch plate.

Silver Bells Edition (a.k.a. Mendacity Steel) Aluminum plated with a bright chrome finish to look like our popular (and relatively rather expensive) Veracity Steel designs. While it weighs less than Veracity Steel because the housing is actually aluminum, the surface finish is typically actually a bit more cosmetically uniform and bright due to the use of fluidic plating rather than mechanical polishing. Rear cover plate is stainless steel in a textured black powder coat.

Aerospace The quintessential retro-futurist finish, in clear anodized aluminum. Black switch and rear cover plate.

Tactical Understated gravitas, in black anodized aluminum. Black switch and rear cover plate.

VHS A vaguely Vaporwave white and light-gray textured finish. Rear cover plate is texture white.

K2 This minimalist textured white over machined aluminum pairs perfectly with anything. Option for a pink or white switch plate. Rear cover plate is texture white.

Aperture This unique metallic gray textured powder coat over machined aluminum is similar to the type used on some limited-edition Leica cameras and other high-end photography equipment. Comes with a black switch plate. Rear cover plate is texture black.

Sunset Blvd This matte (very faintly textured) pink over machined aluminum has a satisfyingly chalky pastel look. It is very challenging to apply and often requires multiple coats (hence its higher price), but the result is dreamy. Comes with a white switch plate. Rear cover plate is texture white.

Veracity Steel Hefty stainless steel meticulously hand-polished in the heart of Los Angeles by skilled metal artisans. (Like any hand-polished stainless piece, microscopic polishing lines and depressions will be visible up close at certain angles in bright light, but I work with a firm that gets the parts as close to a true mirror as humanly possible.) The Veracity option nearly doubles the weight of the Grail. Comes with a black switch plate. Rear cover plate is texture black.

Tech specs

Thanks to the steel rear cover weight (even on models with an aluminum housing) and thick internal geometry, the powder coated Heavy Grails weigh in at around 3.3 pounds (1.5kg) when fully built, and the Veracity Steel at an astonishing >5.5 pounds (2.5kg).

Dimensions: 320mm long x 129mm wide x 33mm tall (at back). Typing angle: 8 degrees.

HHKB compatibility

The Heavy Grail supports the HHKB Pro 3 Classic series (the current, USB-C form sold by Topre/Fujitsu). Note that it 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). An earlier Heavy Grail version supported the Pro 2 HHKB (USB-Mini), but that is no longer supported.

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. You can watch my full build instruction video here.

Arcane technical notes

(Don't worry if you don't know what any of this means.)

Pro 3 Hybrid models If you venture to use a "Pro 3 Hybrid" model with a Heavy Grail, you'll lose the battery functionality, 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 (the metal housing may interfere with the bluetooth range), but hobbyists who have experimented with this usage report that it's feasible. YMMV.

Use without gasket You can use the Grail without the isolation mount gasket, 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 from Topre that have extended length to offset for silencing rings.

Dip switches The dip switches are accessible through the rear cover plate, as shown below.

Nota bene

This is a DIY kit for keyboard tinkerers and hobbyists. It is an aftermarket upgrade housing and does not include the keyboard itself or keycaps (even though product images may show it with those for illustrative purposes). While the build isn't difficult, it does require taking apart your OEM keyboard. This may invalidate your keyboard warranty, and by purchasing you agree to take on that project and its results at your own risk. (But, of course, that's also part of the fun.) Of course, I'm always here to answer any questions by email if any arise during your install.