GRAM Slim
GRAM Digital Controllers
GRAM Slim
Overview
The GRAM Slim is a leverless controller developed by GRAM Digital Controllers and released in 2023. It was designed as a low-profile alternative to existing leverless controllers, with a chassis height of 10mm. The controller was discontinued in 2025, though design files remain available for DIY construction.
Development
Open Source Release
On May 24, 2023, GRAM Digital Controllers published the complete design files for the GRAM Slim on GitHub under the GPL-3.0 license. The repository includes:
- STL files for frame and button cap printing
- Fabrication files for aluminum top and bottom panels
- PCB Gerber files
- Assembly documentation
- Template DXF files for panel customization
Technical Specifications
Physical Characteristics
The chassis height of 10mm was achieved through a “floating” switch design, where the switches use the top panel as a mounting plate.
Materials
Frame: Injection-molded polybutylene terephthalate (PBT)
Top Panel: Depending on variant:
- Aluminum PCB
- Powder-coated aluminum
- Powder-coated aluminum with UV Printing (Genesis X2)
Bottom Panel: Depending on variant:
- Aluminum PCB
- Powder-coated aluminum
Button Caps: Injection-molded PBT, 24mm diameter
Switch Configuration
The controller contains 21 mechanical switch positions, all using Kailh Choc V1 switches mounted in PG1350 hot-swap sockets.
Stock Switch: Kailh Choc V1 Red Pro
- Actuation force: 35g
- Switch type: Linear, low-profile
- Hot-swap socket: PG1350
DIY Construction
Bill of Materials
Electronic Components:
- 21× Kailh Choc V1 switches (Red, Red Pro, or Whites)
- 21× PG1350 hot-swap sockets
- GRAM Slim PCB, designed by Quark
Mechanical Components:
- GRAM 24mm Choc Keycap Buttons (3D print from STL files or purchase)
- GRAM Slim Frame (3D print or purchase)
- Top and Bottom panels (order from fabrication service)
- 7× M5×0.8 8mm Low-Profile Socket Head Screws
- 7× M5×0.8 Round-Base Weld Nuts
Optional:
- USB-C to GCC cable
- USB-C to USB-A cable
Recommended Print Materials
Frame:
- LEDO 6060 resin
- Black resin
- PA12-HP Nylon
Button Caps:
- LEDO 6060 resin
- 8001 Transparent resin
Assembly Process
- Frame preparation (print or purchase)
- Insert PG1350 sockets into PCB
- Press switches into sockets
- Attach keycaps to switch stems
- Secure panels using M5 screws and weld nuts
- Flash firmware via USB
No soldering is required for switch installation.
Retail Package
The controller was sold with:
- GRAM Slim controller (pre-assembled)
- GRAM neoprene soft case
- Braided USB-C to GCC cable (1.8m)
- Braided USB-C to USB-A cable (1.8m)
Optional Accessories
- Replacement button sets
- Alternative switches (Kailh Choc V1 variants)
- Printed aluminum top panels
- Replacement frames
- Hard-shell carrying cases
Version History
- GRAM1 - 5 units made
- Firmware: Pico-Rectangle
- GRAM-OF1 (formerly GRAMv2?) - 16 units made
- Firmware: Pico-Rectangle
- Firmware: Pico-Rectangle
- GRAMv2 (rectangle corner release?)
- GRAM Slim Smash v3
- Firmware: Haybox
- GRAM Slim Smash v3.4
- Firmware: Haybox
- GRAM Slim v4 - Screwless?
- Firmware: Haybox
Discontinued (2025)
- Production ceased