- Stock: 50
- Model: Airtripper Bowden BSP
The Airtripper V3 BSP is a direct-drive Bowden extruder for 1.75mm filament. Its MK8 drive gear mounts directly onto the NEMA 17 motor shaft without reduction gears, while the extruder remains attached to the printer frame and feeds filament to the hotend through a PTFE tube.
This arrangement reduces moving mass on the toolhead and is particularly useful on delta printers, fast machines and multiple-hotend configurations. The Airtripper design was historically used on the Sumpod and Rostock delta printer, although it can also be adapted to other Bowden machines with a suitable mounting bracket.
The motor is optional. The main photograph shows the assembly fitted to a NEMA 17 motor, but the motor is included only when the corresponding option is selected.
How it works
The MK8 drive gear feeds the filament directly as the motor turns. A 608ZZ bearing presses the material against the toothed groove, while two springs allow the pressure to be adjusted. An MR105ZZ bearing supports the outer end of the 5mm motor shaft.
The outlet uses a 1/8 BSP pneumatic fitting for 4mm outside-diameter tubing. For 1.75mm filament, a 4 × 2mm PTFE tube is recommended and sold separately.
Main specifications
| Design | Airtripper Direct Drive Bowden Extruder V3 BSP |
|---|---|
| System | Remote Bowden feeder with direct drive and no reduction gears |
| Filament | 1.75mm |
| Drive gear | MK8 for a 5mm shaft |
| Idler bearing | 608ZZ, 8 × 22 × 7mm |
| Shaft support bearing | MR105ZZ, 5 × 10 × 4mm |
| Outlet fitting | Male 1/8 BSP for 4mm tubing |
| Recommended tube | 4mm OD × 2mm ID PTFE, not included |
| Motor | NEMA 17, optional according to selection |
| Printed-part material | ABS |
Compatibility
The Airtripper can be installed on a 3D printer using:
- 1.75mm filament.
- A Bowden extrusion system.
- 4mm outside-diameter tubing.
- A NEMA 17 motor with a 5mm shaft.
- A rigid mounting point compatible with the printed body.
- A controller and stepper driver configurable for the selected motor.
The design is historically documented on Sumpod and Rostock printers. It may be adapted to other delta, CoreXY, Cartesian, Prusa or P3Steel machines, but mechanical compatibility is not automatic. The mounting bracket, available space and filament-path orientation must be checked.
It is not designed for 2.85 or 3mm filament. It should not be regarded as an extruder optimised for very soft flexible materials, because there are short unsupported sections around the MK8 gear and the Bowden system itself adds friction and elasticity.
Assembly and adjustment
- Attach the printed body to the NEMA 17 motor using the appropriate screws.
- Fit the MK8 drive gear for 1.75mm filament and align its groove with the filament path.
- Tighten the MK8 grub screw against the flat section when using a D-shaped motor shaft.
- Position the MR105ZZ bearing so that it supports the end of the shaft without forcing or misaligning the motor.
- Install the 608ZZ bearing, its axle, the moving idler housing and both springs.
- Adjust both springs evenly and use only enough pressure to prevent slipping.
- Install the BSP fitting without overtightening it, as excessive torque may crack the printed socket.
- Cut the PTFE tube square and insert it fully into the fitting.
Excessive idler pressure may mark or deform the filament, increase motor load and reduce feeding consistency. If the gear slips, also check the hotend temperature and condition before increasing spring tension.
Motor selection and configuration
The kit can be selected without a motor or with a 17HS4401 NEMA 17 motor. Any alternative motor must have a 5mm shaft, NEMA 17 mounting geometry and enough torque for ungeared extrusion.
Driver current must be configured for the motor actually installed and for the regulation method used by the controller. Do not directly copy a current setting from another printer, as RMS and peak ratings and available cooling may differ.
Marlin calibration
There is no universal steps-per-millimetre value for this extruder. Effective drive-gear diameter, microstepping, idler pressure and the selected motor all affect the result.
With the hotend heated, mark the filament, command a slow extrusion of a known length and measure the actual movement. Calculate the corrected value with:
new_E = current_E × commanded_distance / actual_distanceApply and store the value with:
M92 E<new_value>
M500M500 requires EEPROM support. Repeat the measurement until extrusion is consistent.
Klipper calibration
As this is an ungeared direct-drive feeder, a gear_ratio setting is normally not required. Calibrate the rotation_distance parameter instead:
new_rotation_distance =
current_rotation_distance × actual_distance / commanded_distanceUpdate the value in the [extruder] section, restart Klipper and repeat the slow extrusion test. The value must be measured on the actual unit rather than copied from another MK8 extruder.
RepRapFirmware calibration
Configure extruder microstepping with M350 and steps per millimetre with M92 E.... Use the same correction formula as for Marlin:
new_E = current_E × commanded_distance / actual_distanceOnce verified, enter the final M92 E... value in config.g. RepRapFirmware generally recommends 16 microsteps with interpolation when supported by the driver, but the installed electronics must be checked.
Kit contents
- ABS printed parts.
- 1 × MK8 drive gear for 1.75mm filament.
- 1 × 608ZZ bearing.
- 1 × MR105ZZ bearing.
- 4 × M3 washers.
- 4 × M3 nuts.
- 1 × M3 × 25mm screw.
- 2 × M3 × 30mm screws.
- 1 × M3 × 6mm screw.
- 1 × M3 × 10mm screw.
- 2 × M3 × 40mm screws.
- 2 × pressure springs.
- 1 × 1/8 BSP pneumatic fitting for 4mm tubing.
- 1 × 17HS4401 motor only when that option is selected.
PTFE tubing is not included.
