P3STEEL by HTA3D - DIY Kit

The HTA3D P3STEEL is a customisable DIY 3D printer kit with a steel frame, direct drive and an open architecture based on the RepRap/P3Steel family. Developed by HTA3D around 2015, it remains a functional, repairable machine and a particularly valuable way to learn how 3D-printer mechanics, electronics and firmware work.

Its single-extruder configuration has aged especially well: it avoids the complexity of aligning two fixed nozzles, keeps the filament path short and makes each system understandable to build, calibrate and modify. The kit is supplied unassembled, with firmware loaded and the drivers adjusted for the selected configuration.

Main features

Build volume and external dimensions are nominal. Actual usable travel may be affected by the assembled parts, build-surface clips, origin, firmware and assembly tolerances.

Why it still makes sense

• Genuine learning: assemble, wire, configure and calibrate every subsystem.
• Rigid frame: the steel structure provides a stable, durable base.
• Open architecture: Mega, RAMPS, Marlin, V6, NEMA 17, GT2 and 8 mm guides are familiar, repairable technologies.
• Direct drive: the short path aids filament control and can handle flexible materials well when the hotend and profile are suitable.
• Extensive documentation: HTA3D maintains illustrated instructions and an assembly video series.
• Customisation: choose the frame, Z drive, hotend, nozzle, bed and linear bearings.

It is not a current high-speed printer and does not include automatic levelling, networking, an enclosure or modern compensation systems as standard. Correctly assembled and tuned, it remains capable of producing useful, good-quality parts, especially with common materials and speeds appropriate to its architecture.

Available options

The combination selected when ordering takes precedence over photographs and documents from previous batches.

Printed parts can be selected in black, blue, red, white, green or yellow in the current selector. Colour availability may vary.

Kit contents

The kit groups the modules required to build the printer in the selected configuration. Specific components may change with options and stock evolution.

For repairs or partial rebuilds, see the original HTA3D P3Steel direct extruder, HTA3D P3Steel hardware kit and galvanised P3Steel frame. Compatibility with modified community machines must be checked part by part.

Direct extruder, hotend and materials

The extruder motor moves with the X carriage. The MK8 gear pushes filament directly into the V6 through a short, constrained path. This simplifies retraction and can provide good control of flexible materials, although it adds moving mass compared with a modern Bowden system.

• PTFE-lined V6: offers a tightly guided path for common and flexible materials, but the tube approaches the hot zone. Respect the thermal limit of the installed PTFE.
• All-metal V6: removes PTFE from the melt zone and can support higher-temperature materials when the sensor, heater, wiring and rest of the system are also suitable.
• Titanium and Brass: a titanium heatbreak changes the thermal transition, while Brass components provide greater mass and conductivity than aluminium where included. Neither removes the need for cooling and calibration.
• PLA, PETG and common materials: natural applications with the correct profile and surface.
• ABS, ASA, nylon or PC: may require drying, a dedicated surface, higher temperatures and environmental control. The printer is open by design.
• Flexible filament: direct drive is beneficial, but hardness, guidance, idler pressure, nozzle and flow still determine performance.

There is no universal maximum temperature for every option. The safe limit is set by the lowest-rated component among the sensor, PTFE, heatbreak, heater, wiring, fan, block and firmware.

M5, coupled T8x8 or integrated T8x8

• Original M5: retains the historical solution and suits faithful builds or maintenance of an existing unit.
• T8x8 with couplers: uses separate lead screws joined to the motors, allowing either part to be replaced independently.
• Motor with integrated T8x8: removes the rotor-to-screw coupler but requires replacing the complete assembly if either element changes.

Each variant requires matching printed parts and configuration. Never copy M5 steps per millimetre to T8x8 or assume every lead screw sold as T8 has the same lead.

Assembly and commissioning

1. Assemble and square the frame and Y axis before locking and tensioning the system.
2. Install the selected Z variant and make both sides of the X axis level.
3. Prepare the bed for its exact model and wire it for 12 V according to the matching diagram.
4. Assemble the extruder, orient the MK8 gear and V6 block correctly, fit both fans and leave enough cable for full travel.
5. Install the PSU, earth, switch and electronics with power disconnected.
6. Power on to inspect the LCD and fans without requesting full movements.
7. Test the hotend at a low temperature and the bed at about 40 °C, confirming that the correct sensor responds.
8. Check each axis direction and endstop separately before full homing.
9. Level both Z sides, manually level the four bed corners and test the full travel without collisions or cable tension.
10. Calibrate extrusion, flow, PID, first layer and the material profile before increasing speed.

Marlin configuration

Marlin on Mega/RAMPS is the original and most natural configuration. Historical M5 and T8 downloads remain available, but firmware supplied with the kit and prepared for its options takes precedence over old files.

1. Physically identify RAMPS 1.4 or 1.5 and the installed Z transmission.
2. Check the board, EXTRUDERS 1, volume, motor directions, endstops and limits before movement.
3. Do not copy Z steps between M5 and T8x8. Confirm the actual lead of the installed screws.
4. Select temperature tables for the installed sensors. The documented bed uses a 100K Beta 3950 NTC and commonly corresponds to table 11 with a 4.7 kΩ pull-up; do not apply that setting to the hotend without identifying its sensor.
5. Calibrate extruder steps with M92 and PID with M303. Review values using M503 and save with M500 when EEPROM is enabled.
6. M600 requires advanced pause and related functions to be enabled in the build.

Converting to Klipper

Mega 2560 and RAMPS can act as a Klipper MCU, but conversion is not part of the supplied configuration. It requires a host, reflashing the board and creating a configuration for the actual revision and wiring.

Pins, directions, thermistors, rotation_distance, PID and limits are not universal. In the original architecture both Z motors usually share one driver; do not define independent channels without rewiring and verifying the electronics. Klipper can provide a current interface and tools, but it does not turn the mechanics into a high-speed printer.

Assembly documentation

HTA3D maintains an illustrated series covering the frame, M5 and T8 variants, bed, extruder, PSU, electronics, commissioning and flow calibration:

• Frame and Y axis.
• X/Z axes for M5 or X/Z axes for T8x8.
• Direct extruder.
• Electronics and wiring.
• Commissioning.

The tutorials cover several historical revisions. Follow the branch matching the supplied options and ask before changing power wiring or loading different firmware.

P3STEEL, P3STEEL DUAL or 3DSteel V2

It is for you if

• You want to learn 3D printing from mechanics and wiring through to firmware.
• You value a steel structure, familiar components and a repairable machine.
• You prefer the simplicity and short path of a single direct extruder.
• You enjoy tuning and improving an open project.
• You need an original HTA3D P3Steel or want to maintain an existing unit.

It is not for you if

• You require a ready-to-use printer with automatic levelling, networking and automated profiles.
• Your priority is high-speed printing or a factory-enclosed build chamber.
• You do not want to assemble, verify wiring, level manually or learn calibration.
• You prefer a more modern platform for a moderate additional investment; in that case, consider the 3DSteel V2.