Informational guides for custom mechanical keyboards and related hardware

Graystudio Think6.5

Key Information

  • Type: 65%
  • Vendor: Graystudio
  • Designers: Airpotter and Oldcat
  • Interest check: Geekhack
  • Group buy: Geekhack, 13th to 30th April 2019
  • Price: $299.98 (normal version), $650 (brass version)
  • Units: 650 (normal), 25 (brass, not all shipped), unknown number of extra special editions
  • Shipped: late October through early December 2019 (normal version), January 2020 (finished brass plus special editions)
  • Community: Discord
  • Firmware: QMK, hotswap PCB configurator, solder PCB configurator, VIA
  • Connector: USB Type-C


The Think6.5 is a custom mechanical keyboard from Graystudio, offered in a number of different configurations, and in large numbers compared to most group buys. Interest in the board started in late February 2019 and built strongly over the next 6 weeks as new renders and pictures of prototypes were made available on Geekhack and Instagram, showing off the board's myriad configurations and how it might look with popular keysets.

The board combines a fully-integrated switch plate, brass bottom weight, badged blocker (although the board was also offered in badgeless form), top and bottom PCB-based lighting, 6.5° typing angle, and support for a number of fairly standard 65% layouts.

Graystudio were ambitious with the amount of potential customisation in materials, colours and layout support, letting users pick from 4 different switch plate layouts, 2 different coloured polycarbonate versions, 5 different coloured anodised aluminium versions, 2 extra weight colours with matching brass badges, and 9 other anodised aluminium badges which were available separately or as a collection in a custom storage case.

Allowing users to put together almost 800 different combinations of the Think6.5 normal version resulted in a complex buy for Graystudio to manufacture and ship. All were eventually shipped, but it wasn't without difficulty for the studio to complete.

The end result is a warmly received 65% board that users seem to really like, especially in terms of the look and feel, the sound, and the potential for customisation to match keysets and the user's other aesthetic desires.


Graystudio have been active since early 2018 and designed 3 other boards prior to the Think6.5. The COD67 is a 60%-ish with a unique layout, innovative RGB underglow and a striking angular case design. Limited to 75 units worldwide, the group buy started in February 2018 and started shipping in June that year. The HB85 is a proper chonker with an almost full-size layout that began manufacture in late 2018 and was shipped via ZFrontier starting in January 2019.

The Space65 was Graystudio's most recent board prior to the Think6.5, and at the time of writing has just sold out of the very last special production run in a number of exclusive and very limited colour finishes. It's a 65% board inspired by the launch of the Voyager 1 space probe, and by the designer's love of the Apple II. It started the group buy process in very late 2018, and the first batch started shipping worldwide in mid-June 2019.

Group Buy Options

The normal Think6.5 could be ordered with a wide range of extras, on top of the default gold PVD-coated brass back weight and badge that came with all boards:

  • Aluminium badges (all $25 each)
    • Midnight Blue, Tiffany Teal, Wavez Green, Rose Gold, Black, Grey, Silver, Red
  • 9-piece badge set plus case ($110)
  • PVD coated back weight and badge (both $50 each)
    • Rose Gold, Black
  • Extra PCB ($50 each)

7 different case colours, 4 different layouts, 9 different badges and 3 different back weights mean that there are 756 different normal Think6.5 combinations that can be put together. A small number of orders of the base model Think6.5 were actually unique, yet well over half of the possible combinations were ordered just 10 times or less.

There are 4 boards that were uniquely ordered, all aluminium badgeless with compatible PCBs: just one each of those exists, in Rose Gold, Tiffany Teal, Midnight Blue and Wavez Green. There are some other interesting statistics from the public order tracking data:

  • 76.2% chose polycarbonate over aluminium
  • 75.4% chose ANSI over compatible
  • 81.8% chose badge over badgeless
  • There are only 70 black polycarbonate boards with badge
  • There are only 10 black polycarbonate boards without badge
  • There are only 9 Tiffany Teal boards
  • There are only 30 Wavez Green boards
  • There are only 24 Midnight Blue boards
  • There are only 28 Space Gray boards
  • There are only 27 Rose Gold boards
  • There are 297 frosted polycarbonate boards!

There were also two potential aluminium layout/badge/colour combinations that nobody ordered: ANSI badgeless Tiffany Teal, and compatible badged Tiffany Teal. Tiffany Teal was the least ordered colour in general, contributing just 1.8% of the order volume.

The biggest seller was ANSI frosted polycarbonate with badge, which makes sense since it was the leading configuration pushed by Graystudio during the interest check and group buy phases.

Brass Problems

The original plan for PVD coated brass special editions fell apart in early 2020 with the announcement from Graystudio that only the black version was produced. The studio's PVD factory wasn't able to produce the gold and rose gold brass versions to a high enough QC standard, so only the black version shipped to buyers of that variant. Customers for the gold and rose gold colours were offered a full refund and discount on future Graystudio products.

The black brass version looks fantastic!

Black brass Think6.5 wearing SA Olivia from Discord user Audiobs!

Black brass Think6.5 wearing SA Olivia from Discord user Audiobs!

Special Editions

In early January a number of limited availability special editions were made available on the Graystudio online store, to mark the successful completion of the group buy after the black brass edition was finally shipped. Only a small number of boards were made available, with the most sought after being colours not produced during the original group buy, including an e-yellow version with black badge, and an e-white version with black badge.

e-yellow Think6.5 wearing GMK Metropolis from Discord user Moridin!

e-yellow Think6.5 wearing GMK Metropolis from Discord user Moridin!

Box Contents

While the Think6.5 could be ordered with a large potential combination of extras, the base contents of the custom Graystudio packaging were the same. You got the board with PCB pre-installed and the case pieces pre-attached, at least one set of hex key wrenches for the associated M2 and M3 bolts, a set of clear bumpons, plastic washers to go under your stabiliser screws, and the standard gold coloured PVD-coated brass weight and badge (if ordering the badge version) already fitted to the board.

If you ordered any extra badges or weights, they came outside of the main box packaging. The box was also shipped in an impressive outer bubble protection to avoid box damage during shipping, which worked really well, along with a note about not overtightening the bolts due to the receiving thread in the polycarbonate case being weaker than something machined out of metal.


The Think6.5 is a 2-piece 65% design with 6.5° typing angle in a classic wedge-like shape. The top case features an integrated 4.5mm switch plate and badge blocker on the rightmost edge of the board (badgeless version also available).

RGB lighting is only completely visible on the frosted clear polycarbonate version of the board. The black polycarbonate and aluminium cases do show diffuse light above the badge, and light from the Escape key is visible depending on your switch housing, but the underglow is sadly invisible.

The case has rounded corners with a small bevel around the outer edge of the top case, and a more pronounced beveled area on the right hand side, running parallel to the right edge of the badge. That bevel is present even on the badgeless boards, slightly distracting from the otherwise clean design of the board. Other than the badge area detailing the board is clean on the top.

The bottom of the board shows off the PVD-coated brass weight, which is most completely visible on the frosted polycarbonate version. On the black polycarbonate and aluminium versions, only the lower badge section will be visible through the cutout. The case screws are around the bottom edge, and the left and right edges get a fairly pronounced bevel to give the bottom case design a little bit of visual distinction. They arguably make it ever so slightly easier to pick up, too. Underneath the logo you'll find “©OLDCAT AND AIRPOTTER” engraved.


The PCBs were designed by DEMO, and feature an Atmel/Microchip ATmega32U4 MCU, USB Type-C connector (although it's just USB 2.0 mode when connecting to the host) and a chain of 22 WS2812 LEDs for lighting. If you look at the pictures in the Build section, you can see there's a reset button (circled in orange) and a set of pads you can temporarily bridge to debug LED issues (marked JL and ringed in green, on the left).

The ATmega32U4 powering the PCB runs the QMK firmware, and the PCB has VIA support.


The WS2818 LED array on the PCB allows the firmware to address each LED individually. At the time of writing the currently available QMK firmware the board has all of its LEDs controlled as a single group, however in-development firmware for the board allows each LED region to be addressed separately with static lighting configurations, as you can see in the image below.

The board has 14 LEDs on the bottom of the PCB for underglow (originally just 8, but Graystudio increased it after initial prototypes came back), 4 under the Escape key, and 4 above the badge which diffuse through the top case above the badge.


The Think6.5 supports 4 basic layouts, ANSI and “compatible” (basically European ISO) with and without a badge. The solderable PCB is the only one to support non-ANSI layouts, so be sure and get that version if you're looking for a Think6.5 that's configurable like that.

The solderable PCB is also the only one to support split backspace and split left shift, and a 7U spacebar with appropriate bottom row. The hotswap board is much more limited in comparison with the choice of standard or stepped caps lock the only thing you can influence.


The build procedure is straightforward on the Think6.5 and is effectively the same whether you're building with the solderable PCB or the hotswap PCB. The key thing to note is that the board uses different bolt threads, lengths and head sizes in different places on the build.

If you misplace the 2 different sized hex key wrenches you get with the board, Torx T6 and T8 bits will also work just fine. Check the following images if you're not sure what goes where. The board uses two 6mm M3 screws to retain the badge (not pictured).

If you're building one of the polycarbonate boards, be very careful screwing in the retaining bolts that hold the top and bottom case together. The bolts all go through the PCB and screw into a threaded hole in the top case. Because it's plastic and the bolts are metal, it's very easy to overtighten which will rethread the hole and stop it retaining the bottom to the top.

The bolts go through the outer holes in the PCB, but they don't thread through them. But, because the clearance tolerance is quite small it can feel like you're threading through them, and it's also easy for the bolt thread to get caught on those holes when unscrewing making it hard to get the bolt out. When opening the case, always make sure that the 8 bolts are completely free of the PCB holes before attempting to separate the top and bottom case.

As you can see from the picture of the PCB above, the two screws holding the badge are accessible (coloured red and on the left in the picture) without having to remove the PCB.

It's a straightforward build if you're mindful of that, and ongoing maintenance to change the badge or get access to the reset button on the bottom of the PCB is easy enough.


The Think6.5 runs the popular QMK firmware, with online configurator support for the hotswap PCB and the solder PCB in ANSI layout in the mainline branch of QMK for a while now, courtesy of MechMerlin!

There are user contributed keymaps for the Think6.5 QMK that also support the ISO layout that's possible on the solderable PCB variant, and that have more control over the static lighting configuration of the board. The static lighting control continues to be developed and test firmware is available:

For that test firmware the following static lighting control is available (look at the layouts for the location of the Fn key):

Fn + A/Z   = Escape hue +/-
Fn + S/X   = Escape saturation +/-
Fn + D/C   = Escape value +/-

Fn + F/V   = Badge hue +/-
Fn + G/B   = Badge saturation +/-
Fn + H/N   = Badge value +/-

Fn + J/M   = Underglow hue +/-
Fn + K/,   = Underglow saturation +/-
Fn + L/.   = Underglow value +/-

Fn + Up    = Range cycle
Fn + Left  = Toggle Escape LEDs
Fn + Down  = Toggle Badge LEDs
Fn + Right = Toggle Underglow LEDs

If you'd like to get started with QMK but you aren't sure where to start, try the excellent documentation or ask the user community. In particular, look at the section on flashing with the QMK Toolbox software.

VIA Support

VIA support for the Think6.5 was added in v1.2.5, so download VIA for your preferred operating system and install it. Make sure your Think6.5 is flashed with the firmware listed on the VIA website, then launch VIA, where you can switch to the Configure tab and configure your board.

If you want to enable split backspace, ISO Enter, split left shift or a 7U bottom row for your board, if that's how you've set it up, check the Layouts section in the Configure tab. You can see below that ISO Enter and Split Left Shift are enabled, and the layout below reflects that.

Adjustable Layouts

Adjustable Layouts

While VIA support doesn't allow you to control each of the individual LED ranges on the Think6.5, it does let you control all of the LEDs together, with full RGB and brightness control.

Potential Issues

There is one small potential issue that you might encounter with your Think6.5, but thankfully it's rare. If you aren't able to fix it yourself then you can get support from the user community and Graystudio directly. On some PCBs, because the LEDs are connected in a chain, one of the LEDs can have poor contact to the PCB and therefore it stops working and also stops every other LED in the chain from working correctly too.

If that happens on your board, you can try briefly bridging the pads marked JL (circled in green on the picture of the bottom view of the PCB in the Build section). Bridging those pads temporarily pulls all of the LEDs to ground, resetting them. Experiment with bridging JL to try and debug the issue.

If that doesn't help, it's possible that the first affected LED has a bad contact with the PCB. You can reflow the affected WS2818 LED to remake its connection to the PCB, which should fix the issue. If that doesn't help, join the user community and they'll help you out.

The clearance between the PCB and the bottom case when fully assembled is very small, so make sure you fit your PCB as tightly as possible with your switches in as tightly as you can get them. At least one build reported by a user was off by enough to permanently hold down the PCB reset button when the top and bottom case were assembled, causing him to have to remove the PCB's reset button.

Support and Community

The Think6.5 has an active community on the Graystudio Discord in the #think65° channel, where you can find many Think6.5 users who have built their boards ready to help out.

Frosted polycarb, gold PVD badge, GMK Wavez from Discord user add1ct3dd!

Frosted polycarb, gold PVD badge, GMK Wavez from Discord user add1ct3dd!

Frosted polycarb, rose gold anodised badge, GMK Olivia from Discord user rys!

Frosted polycarb, rose gold anodised badge, GMK Olivia from Discord user rys!

Frosted polycarb, gold PVD badge, GMK Minimal from Discord user sandrasays!

Frosted polycarb, gold PVD badge, GMK Minimal from Discord user sandrasays!

Frosted polycarb, gold PVD badge, PBT Heavy Industry from Discord user Treezussaves!

Frosted polycarb, gold PVD badge, PBT Heavy Industry from Discord user Treezussaves!

e-yellow, GMK Metropolis from Discord user rys!

e-yellow, GMK Metropolis from Discord user rys!

Build Streams

Typing Tests

  • Walker's Keyboard Science - Polycarb Think6.5 + switch filmed T1s lubed with Krytox 205g0
  • Parke Mech - Polycarb Think6.5 + vintage Cherry MX blacks, spring swapped to 63g slow curve, thin lubed with GHv4
  • Didier Bouchard - Polycarb Think6.5 + Tealios v2 67g lubed with Tribosys 3204


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