514 28byj 3d models found
Download or buy, then render or print from the shops or marketplaces.
3D Models below are suitable not only for printing but also for any
computer graphics like CG, VFX, Animation, or even CAD. You can print these 3d models on
your favorite 3d printer or render them with your preferred render engine.
Please note that the 3D model database is only a Search Engine. You should
visit the original websites. Most of the models can be easily imported and rendered
with Autodesk 3ds Max, Maya, Blender, C4D, and Sketchup. Check for online
3d model conversions tools for your file format.
Shown 1 of
5 pages
thingiverse
free

28BYJ-48 by StudioPieters
...28byj-48 by studiopieters
thingiverse
28byj-48 model
thingiverse
free

COREXY 28BYJ-48 by berezhinski
...corexy 28byj-48 by berezhinski
thingiverse
remix mount for motor 28byj-48
thingiverse
free

28BYJ-48 Turret by acki42
... turret by acki42
thingiverse
turret based on 28byj-48 geared stepper motor.
bom:
2x 28byj-48
3x ball bearings 8/22 (skateboard)
thingiverse
free

28byj-48 box by fcfly
...28byj-48 box by fcfly
thingiverse
box for stepper motor 28byj-48, for time lapse
thingiverse
free

28BYJ-48 Actuator by igortarasiuk
...28byj-48 actuator by igortarasiuk
thingiverse
step motor 28byj actuator. i made for car...
thingiverse
free

Suporte_Horizontal 28BYJ-48 by rdoliveira
...suporte_horizontal 28byj-48 by rdoliveira
thingiverse
suporte horizontal para o motor de passo 28byj-48
thingiverse
free

28BYJ-48 spacer by besalel
...28byj-48 spacer by besalel
thingiverse
1mm spacer for 28byj-48
scale z according to your needs.
thingiverse
free

double 28byj-48 support by kamiserg
...double 28byj-48 support by kamiserg
thingiverse
double 28byj-48 support
thingiverse
free

Wheel for 28BYJ-48 Servo by robotonics
...wheel for 28byj-48 servo by robotonics
thingiverse
wheel for a 28byj-48 servo
thingiverse
free

Wheel for 28BYJ-48 Servo by robotonics
...wheel for 28byj-48 servo by robotonics
thingiverse
wheel for 28byj-48 servo
thingiverse
free

28BYJ-48 Stepper Motor in OpenSCAD
...28byj-48 stepper motor in openscad
thingiverse
28byj-48 stepper motor in openscad
thingiverse
free

28BYJ Flange by GWPM
...28byj flange by gwpm
thingiverse
flange to connect this cheap stepper
thingiverse
free

28BYJ-48 Wheel and Tyre by robotonics
...28byj-48 wheel and tyre by robotonics
thingiverse
wheel and tyre for a 28byj-48 stepper motor
thingiverse
free

28byj-48 support by floflo50
...
thingiverse
it' a support for 28byj-48 stepper motor. for 90° rotation.motor fixation and support fixation are by 4mm screw
thingiverse
free

28BYJ-48 Stepper Motor by lagrockline
...t in every 3d design.
designed according to the following datasheet: https://datasheetspdf.com/pdf/1006817/kiatronics/28byj-48/1
thingiverse
free

28BYJ-48 to nema 17 adapter by genovese
...28byj-48 to nema 17 adapter by genovese
thingiverse
28byj-48 to nema17 adapter
thingiverse
free

skoba-der.28BYJ-48 5VDC by EkaterinaZ
...skoba-der.28byj-48 5vdc by ekaterinaz
thingiverse
model 28byj-48 5vdc.
thingiverse
free

28BYJ-48 motor housing by ChrisLX200
...motor housing by chrislx200
thingiverse
housing for the ubiquitous 28byj-48 stepper motor that can be screwed to a flat surface.
thingiverse
free

28BYJ-48 Stepper Motor Model by MattGree_
...28byj-48 stepper motor model by mattgree_
thingiverse
a model of the 28byj-48 stepper motor
thingiverse
free

Stepper Motor 28BYJ-48 Arrow by Bojar10
...stepper motor 28byj-48 arrow by bojar10
thingiverse
stepper motor 28byj-48 arrow
thingiverse
free

Wheel and Tyre for 28BYJ-48 Servo by robotonics
...wheel and tyre for 28byj-48 servo by robotonics
thingiverse
wheel and tyre for 28byj-48 servo
thingiverse
free

28BYJ-48 by Jordan_Doerksen
...things that will use this motor i also print this out to use in place of the stepper motor while i design the rest of the device.
thingiverse
free

gauch arrow for a steppermotor 28BYJ-48 by DRN76
...gauch arrow for a steppermotor 28byj-48 by drn76
thingiverse
this is a simple gauch arrow for a 28byj-48 steppermotor.
thingiverse
free

28byj-48 Parametric Peristaltic Pump by ysahin
...28byj-48 parametric peristaltic pump by ysahin
thingiverse
i added adapter for 28byj-48 stepper motor
thingiverse
free

28BYJ-48 Stepper Motor Wheel by Magdel16
...28byj-48 stepper motor wheel by magdel16
thingiverse
wheel designed to attach to a 28byj-48 stepper motor
thingiverse
free

MOTOR MOUNT 28BYJ-48 by drjcpp
...cpp
thingiverse
motor mount for 28byj-48 used on 2 wheel robot platform, but may be adapted to others. second variation shorter.
thingiverse
free

76mm -28BYJ-48 Stepper Motor Wheel by mr2quik
...per motor wheel by mr2quik
thingiverse
76mm x 32mm / 28byj-48 stepper motor wheel
attach to a 28byj-48 keyed stepper motor shaft
thingiverse
free

28BYJ-48 spacer (pulley version) by besalel
...8byj-48 spacer (pulley version) by besalel
thingiverse
1mm spacer for 28byj-48 (pulley version)
scale z according to your needs.
thingiverse
free

28byj Cover With Tabs by jcane86
...28byj cover with tabs by jcane86
thingiverse
added fastener tabs to secure the stepper holder.
thingiverse
free

Stepper motor 28BYJ-48 by nospoon
... modeling robots https://cad.onshape.com/documents/3eec06b9baf0ee438c7b74eb/w/d5e83df0ce3d40a3bc9a68c6/e/b9a2031d665c8df30c1a3ca0
thingiverse
free

Pulley for 28BYJ-48 stepper motor by matteneder
...r by matteneder
thingiverse
fits perfectly on the shaft of the 28byj-48 stepper motor (no gluing). can be used as a rope pulley.
thingiverse
free

28BYJ-48 Stepper Motor Cover by superwoodle
...r by superwoodle
thingiverse
a simple slide on cover for your 28byj-48 stepper motors. no other hardware necessary for mounting.
thingiverse
free

O-Ring Wheel for stepper 28BYJ-48 by MightyBird
...o-ring wheel for stepper 28byj-48 by mightybird
thingiverse
this is a wheel for an o-ring to be mounted on a stepper 28byj-48.
thingiverse
free

28BYJ-48 Stepper Car by OT12345
...giverse
make your own stepper car with 28byj-48 steppers. im using doubble sided tape to get more grip on the tires, works well.
thingiverse
free

Lego to Stepper 28BYJ-48 Adapter
...simple lego axle to 28byj-48 stepper motor adapter. snug but not too tight fit.
if it doesn't fit your printer over-extrudes.
thingiverse
free

Step Motor 28byj-48 Knob by JohnPhamous
... knob is attached to the spinning axle of a 28byj-48 step motor. the knob was designed to be able to support shortening a string.
thingiverse
free

Stepper 28BYJ hull by hilderonny
... (see testbox.scad)
use <stepper.scad>;
difference() {
cube([40,50,4],center=true);
translate([0,0,2.5])28byj();
}
thingiverse
free

Holder for 28BYJ-48 by Druidosh
...holder for 28byj-48 by druidosh
thingiverse
based on http://www.thingiverse.com/thing:1017109/#files stepper holder.
thingiverse
free

28BYJ-48 by WAIT24
...ing, those for incorporation confirmed at design time.
the design tools read as an additional object, to confirm the final image.
thingiverse
free

Customizyble mount for stepper 28BYJ-48 by MightyBird
...erse
tis is a mount for the cheap stepper 28byj-48. you can customize the open scad file by editing the values of the variables!
thingiverse
free

Mockup stepper 28BYJ-48 by JobSmolders
...mockup stepper 28byj-48 by jobsmolders
thingiverse
for designers. 123d file included :-)
thingiverse
free

Worm drive for 28byj-48 stepper or flex3drive shaft by revillete
...worm drive for 28byj-48 stepper or flex3drive shaft by revillete
thingiverse
this worm drive has a flex3drive or 28byj-48 mount
thingiverse
free

Robotic Arm 28BYJ-48 by dmclark
.../youtu.be/kyrb0abdwichttps://youtu.be/oylz2islxoihttps://youtu.be/t3hfwljj1bo
githubhttps://github.com/clarkdm/group-12-connect-4
thingiverse
free

Wheel ( roda ) and support for stepper motor 28BYJ by profjr
...fjr
thingiverse
these are a wheel and a support for stepper motor 28byj
printed on pla using 2.0 layer height and 20 % of infill
thingiverse
free

Model stepper 28BYJ-48 by siderits
...r with uln2003 driver board (without driver board.
used in modeling enclosures.
included an indicator for this stepper motor.
thingiverse
free

Spiral for Step motor(28BYJ-48) by park1107k
... fits in a stepper motor (28byj-48)printed with raft and no supportprinter: maker select 3d printer v2filament: pla 1.75mm, black
thingiverse
free

28BYJ-48 motor mount makerbeam
...28byj-48 motor mount makerbeam
thingiverse
bracket to mount a 28byj48 stepper motor on makerbeamxl.
thingiverse
free

Stepper Bracket (28BYJ-48) by ewoud_design
...stepper bracket (28byj-48) by ewoud_design
thingiverse
stepper bracket designed for the 28-byj-48.
thingiverse
free

GT2 Pulley for 28byj-48 stepper by Arkh01
...y for 28byj-48 stepper mottor.
includes two slots for m3 nuts and set screws but can also be used without with only pressure fit.
thingiverse
free

Gear for 28BYJ-48 stepper motor by makerbard
...ck and pinion gear set example" by dreyfusduke. i altered the gear so that it fits on the shaft of a 28byj-48 stepper motor.
thingiverse
free

Maze mouse wheel for 28BYJ-48 stepper motor by markbenson
...stepper motor by markbenson
thingiverse
a wheel for a maze mouse to fit stepper 28byj-48 http://www.thingiverse.com/thing:122070
thingiverse
free

SMARS - 28BYJ-48 by unclejeff
...e using the code from this link "https://www.thingiverse.com/thing:2312476".
video and files will be updated very soon.
thingiverse
free

28BYJ-48 stepper motor mount by daniovv
...28byj-48 stepper motor mount by daniovv
thingiverse
fits very tight
thingiverse
free

28BYJ-48 5V Stepper Motor Housing and Bracket by robotonics
...ing and bracket by robotonics
thingiverse
housing and bracket for 28byj-48 5v dc stepper motor to be used to add to robot frame.
thingiverse
free

Omniwheel - penplotter -28byj
...-stepper-multiaxis/un2003-stepper-multiaxis.ino for other 28byj stepper projects because of the torque it provides over stepper.h
thingiverse
free

28BYJ-48 Stepper Model by laurb
...28byj-48 stepper model by laurb
thingiverse
this is a model of the common 24byj-48 stepper to use for carving enclosures.
thingiverse
free

stepper 28BYJ T-Slot by tintinz
...stepper 28byj t-slot by tintinz
thingiverse
tslot for smallstepper
p.s i haven't test it yet!
thingiverse
free

gearbox for 28BYJ-48 - 1:4 ratio by Marek_Iksinski
...erse
simple 1:4 ratio gearbox for 28byj-48 stepper motor. output is 5mm shaft (square). need supports on both gears and plate b.
thingiverse
free

China-Stepper for negativ forms 28BYJ-48 / Placeholder by TeeZee
...thingiverse
this is the main part of the 28byj-48 stepper motor. i need it for my projects.
feel free to remix and complete it.
thingiverse
free

Solder Dispenser on 28BYJ-48 by Smoria
...
1x 28byj-48 motor
2x 3mm od teflon tubing
1x 5x20.4mm spring
2x m4 screw
5x m3x8 screw
1x m3 nut and washer
3x m4 nut and washer
thingiverse
free

Drawing Robot 28BYJ-48 Motors by halfluck
... to @henryarnold for his work on the project, @unclejeff for the clever ideas and @3dprintingworld for use of their pulley design
thingiverse
free

28BYJ Stepper Motor Ready Gears Different Sizes by Bojar10
...y gears different sizes by bojar10
thingiverse
8 teeth gear
10 teeth gear
12 teeth gear
gears perfectly fits 28byj stepper motor
thingiverse
free

A simple stand for Stepper motor (5V 28BYJ-48) by orsonyang
...onyang
thingiverse
a simple stand for stepper motor (5v 28byj-48)
its a simple parts could beside breadboard.
all the best :)
thingiverse
free

28byj-48 Stepper Motor Wheel V2 by Magdel16
...28byj-48 stepper motor wheel v2 by magdel16
thingiverse
lighten the load
thingiverse
free

Fish feeder(28BYJ-48)
...
i use this model with esphome for my smarthome. if you want arduino firmware write down in comments. i will add stand and cover
thingiverse
free

Step motor 28BYJ-48 holder for turntable
...step motor 28byj-48 holder for turntable
thingiverse
stepper holder for https://www.thingiverse.com/thing:3723618
thingiverse
free

28BYJ-48 stepper motor by jeremy2nis
...byj-48 stepper motor by jeremy2nis
thingiverse
stepper motor model without driver card.
generaly used in my case with an arduino
thingiverse
free

Lego Case for 28BYJ-48 Stepper Motor by mrhill_icb
...upport brim which can be snapped off after printing.
cut off screw lips from 28byj-48 motor and file flush with the metal housing
thingiverse
free

Pully for 28BYJ-48 Stepper motor by sjhar3d
...pully for 28byj-48 stepper motor by sjhar3d
thingiverse
this is a pully i made for a stepper motor for my robot.
thingiverse
free

Fan duct with a rotating single flap (28BYJ-48)
...youtube.com/watch?v=zkbijifk3dg
it can be printed without support. works with an 120 mm case fan and a 28byj-48 stepper with 12v.
thingiverse
free

Linear mechanism for stepper motor 28BYJ-48 by Trigubovich
...outube.com/watch?v=qyq4cytmsnkhttps://youtu.be/wonaokmsweshttps://youtu.be/9vfqiy_q_j0https://www.youtube.com/watch?v=e2nytcrssvc
thingiverse
free

28BYJ-48 SCAD model by jbeale
...tepper motor at http://arduino-info.wikispaces.com/smallsteppers
slight update 21 july: wire diameter variable name typo fixed.
thingiverse
free

Carusel espacios interactivos - Carousel Motor 28BYJ-48
...carusel espacios interactivos - carousel motor 28byj-48
thingiverse
carusel para espacios interactivos.
thingiverse
free

5v stepper motor for prototyping - 28byj-48 by carlesoriol
...5v stepper motor for prototyping - 28byj-48 by carlesoriol
thingiverse
5v stepper motor for prototyping
thingiverse
free

Dual 28byj-48 Stepper Motor Mounts by Magdel16
...dual 28byj-48 stepper motor mounts by magdel16
thingiverse
2 mount with one print
thingiverse
free

Direct Drive 28BYJ-48 by biocode
...ght, this motor is suitable for very light duty only.
read the instructions for some important considerations before making this.
thingiverse
free

Stepper Motor 28BYJ-48 by RGriffoGoes
... use it to model your stuff!
modeled after real measures and this data sheet: http://robocraft.ru/files/datasheet/28byj-48.pdf
thingiverse
free

Stepper motor base ( 28BYJ-48 ) by Senzu
...ou wish i can create another model with a larger base.
!! in the photo, the holes were drilled after printing !!
hope you enjoy !
thingiverse
free

MK8 extruder with 28BYJ-48 stepper by Branez
...tant by objects, where we have some long overhangs. inside i made some changes to allow printing even soft materials (ninjaflex).
thingiverse
free

28BYJ-48 Extruder by Tinkering_On_Steroids
...5 x2
pneumatic pushfit 4mm / m5 thread x1
mk8 extruder drive gear 26 tooth copper 11 x 11 mm x2
tension spring od 8mm, 14mm x2
thingiverse
free

Tri-Track Robot 28byj-48 Motor Sprocket by ralpha
...me 28byj-48 stepper motors so i made sprocket to use in the tri-track robot.
features:
m3 nut slot
tight fit
reduced shaft length
thingiverse
free

28byj-48 stepper motor holder Crayford/Skywatcher focuser by castropic
...skywatcher 25,5mm focuser
motor control:
arduino ascom focuser pro diyhttps://sourceforge.net/projects/arduinofocuscontrollerpro/
thingiverse
free

Test rig for 28BYJ 5V stepper motor by Badgerbreath
...no.
the purpose of this test mount was to enable test runs of code to check on accuracy of the movements via the 12 raised marks.
thingiverse
free

28byj-48 Motor Halter (Remixed)
... original version which was easily broken because the base was too thin, fixed an issue which caused the stepper cables to break.
thingiverse
free

Robot platform for 28BYJ-48 stepper motors by jdude
...on the other end. put stepper drivers on one mini breadboard and an arduino nano on the other. this is still a work in progress
thingiverse
free

28BYJ-48 Stepper Motor Angle Indicator by TyrannicalTy
...otor, and then pop on the indicator arm.
some people just tape a toothpick to the motor shaft, but this is a nicer solution imo.
thingiverse
free

Robot Wire Lift (28BYJ-48 step motor) by Nessim
...need
28byj-48 step motor
4* m3 screw
m3 tap ( or powerful hand )
usual skate bearing ( ⌀ 8 and 22 by 7 mm )
a controller
thingiverse
free

28BYJ-48 Stepper motor 2 wheel proto platform. by Non-ICE
... wheel cart kit with mounts for 28byj-48 stepper motors. all the mounts are pressed onto the main plate.
nb: not self balancing!
thingiverse
free

28BYJ-48 Stepper Shaft - z-axis Coupler by Solarmax
...herry-60-3d-printer/ by vulcaman. however, they could be used for other printers using the 28byj-48 stepper and 5mm threaded rod.
thingiverse
free

28BYJ-48 Stepper motor holder and top plate by lambros_x86
...s://www.instructables.com/id/automatic-turntable-with-shutter-release/
github: https://github.com/vitaliiuspalenko/turntable_v1.0
thingiverse
free

Stepper motor Part No: 28BYJ-48 by markbenson
...t with the ultrasonic sensor model http://www.thingiverse.com/thing:122136
updated scad as shaft has two flats rather than one.
thingiverse
free

28BYJ-48 Stepper Shaft Coupler M3 by marph
...yj-48 stepper shaft coupler m3 by marph
thingiverse
it works with my print-settings very good. please try and give me a comment.
thingiverse
free

flat 2d plotter for 28BYJ stepper motors
...r-mit-hebel-printmontage-1a/250vac-on-40-on-41-1-stellig?c=86). so it can calibrate itself. no screws are needed but recommended.
thingiverse
free

Step Motor 28BYJ-48 Attachment by GameShifterG
... then simply import the thing you want to move with the step motor, and put this object where you want the step motor to go into.
thingiverse
free

85MM 28BYJ-48 Wheel by Humanisticnick
...enough torque but lack in the speed department. so by making the wheels bigger you can make your little stepper robot run faster!
thingiverse
free

28BYJ-48 stepper to 5/16th in Rod Coupler by papyrus_
...ested, if anyone wants other specific parts for the 28byj-48 steppers just get in contact with me, i would love to talk about it.
thingiverse
free

28BYJ-48 to M4 Coupling by duisenberg
...ce, depending on the application a drop of glue might be needed to keep them in place. the m4 is meant to be fixed by double nut.
thingiverse
free

soporte motor paso a paso pequeño 28byj by Ramos00
...oporte motor paso a paso pequeño 28byj by ramos00
thingiverse
soporte para el motor paso a paso que viene en muchos kits arduino
thingiverse
free

Robot wheel for 28BYJ-48 stepper motor by MakersBox
...r motor by makersbox
thingiverse
based on http://www.thingiverse.com/thing:122305
added thicker hub and hole for m3 set screw.
thingiverse
free

Base for arduino duemilanove, small prototype board and 2 mounts for 28BYJ-48 and ULN2003 by DavidMcDermott
...ingiverse.com/thing:122305 with this board.
this thing is just a simple board to mount two 28byj-48 steppers and arduino board.
thingiverse
free

Polea GT2 de 90 dientes para motor 28BYJ-48 by tximy
...t2 de 90 dientes para motor 28byj-48 , acabo de subir una nueva version que mejora el agarre del eje.https://youtu.be/813-nv2rkyc
thingiverse
free

Telescope Motor Drive using 28BYJ-48 by orly_andico
...10850
a large transfer gear is also required on the equatorial mount's worm shaft - https://www.thingiverse.com/thing:2910620
thingiverse
free

28BYJ-48-5V Scara Bot by 103798
...ect:
arduino with 8 digital pins
4x 28byj stepper
4x driver board uln2003
some nuts & bolts
4x 623zz bearing
4x 608zz bearing
thingiverse
free

Stepper Motor Base for 28BYJ-48
...ted to, amazon.com, smallparts.com and banggood.com. as an amazon associate, i earn a small commission from qualifying purchases.
thingiverse
free

LEGO Controller for stepper 28BYJ by Eisbaeeer
...eer/esp8266-lego-control
https://www.youtube.com/watch?v=qve3-qj_wt8
my son creates his first vehiclehttps://youtu.be/yph7fdz5nrc
thingiverse
free

28BYJ-48 5V based extruder by Vladimir_Trondin
... stepper motors bases extruder.https://www.youtube.com/watch?v=u_v9kl5oibi
hints:
current 120ma/motor
don't use microstepping
thingiverse
free

Gears GT2 for 28BYJ-48 Stepper Motor by Zmei242
...
this gear was created for the stepper motor, it has a landing under its shaft. if the belt slips, then increase the gear by 0.1.
thingiverse
free

28byj-48 Stepper Motor Wheel - 10 cm Circumference by Magdel16
...28byj-48 stepper motor wheel - 10 cm circumference by magdel16
thingiverse
wheel should move object 10cm with every turn
thingiverse
free

Small Gear for 28BYJ-48 Stepper Motor
...rduino cheap stepper motor. driver board included. if you still need to buy the motor, use my link to support me - thank you!! :d
thingiverse
free

Rotating fishing lure dry rack coupling for stepper 28BYJ by nijotak
... torque to rotate the dry rack, and some tweaking on the arduino code may be necessary. motorspeed at around 8 works best for me.
thingiverse
free

2" smart blinds mount 28byj by Clynchp
...55mm wide. the coupling may be different depending on manufacturer but this one will fit a 7mm rod measured from point to point.
thingiverse
free

IKEA Tupplur wall-mount bracket for 28BYJ-48 stepper motor by oyvindkinsey
...from https://easyeda.com/oyvind/28byj-48-motorized-roller in the main housing, avoiding the need for additional boxes and wiring.
thingiverse
free

28BYJ-48 Extruder Ramps Combo Mount by percaine
...rked out great for my mini delta but i made it so it can also work for other printers as well. hope it will be useful to someone.
thingiverse
free

5.5 inch Table for FreeLSS Scanner using 28byj-48 stepper by phiatt
...ulley from vertical mirobot by aut0mata (1017109). the table is on the printer now, i will update this post when it is complete.
thingiverse
free

28BYJ-48 5V Geared Stepper Motor by eeKnud
...th or without a driver board. provided to anyone needing a model. for example, i use it to check my designs for mounting systems.
thingiverse
free

28BYJ-48 Mounting Bracket by jbeale
.... v4 adds a front flange to resist down-tip when pulley belt exits below.
the scad files are provided so you can adjust to suit.
thingiverse
free

28BYJ-48 wheel with set screw (42mm radius) by dacb
...rt. see the attached image of the graph.
for use with something like the apogee robot: http://www.thingiverse.com/thing:648394
thingiverse
free

28BYJ-48 Stepper motor model by B737_400
... motor, so it would be easier to predict needed dimensions.
feel free to message me if there is an error in the drawing or model.
thingiverse
free

Linear actuator with the cheap 28BYJ-48 Steppermotor for litle cabinet doors by BigFunkyMan
...ion of the bearins is bearing is 3x10x4 (623)https://youtu.be/linjw7yttuyhttps://youtu.be/rfw-yclrlvkhttps://youtu.be/anxi_ufbxbo
thingiverse
free

Rotating Platform: Arduino meets 3D Printing | Stepper Motor 28BYJ-48 + ULN2003
... i use the beginner friendly and cheap stepper 28byj-48 with the uln2003 module. i hope you like it.
https://youtu.be/dzgewmql20k