Kossel 3D Printer


The idea of building a Kossel came to me after:

  • Seeing on ReprapWiki – Kossel, that the Kossel uses OpenBeam, which is very similar to 2020 extruded aluminium, except that it is 1515, and as I had already sourced some inexpensive 2020 for my Wilson II 3D printer, in Bangkok, it would not be much of a problem to go and get some more;
  • Coming across HTA3D’s Kossel printed parts, on eBay, for €29.99, and;
HTA3D Kossel parts
HTA3D Kossel parts
  • Having watched the following video on the Micromake 3D printer, that uses 2020 aluminium and is similar to the Kossel (inasmuch as it is a Delta printer). See this explanatory video:

However, as I have stated above, the main reason was that I had the idea of sourcing the aluminium for the Kossel, whilst I was in Bangkok, as aluminium is relatively cheap in Bangkok, when compared to Europe.

See also

Points to note

  1. The STL files for the printed parts listed on RepRapWiki – Kossel and on Github: jcrocholl/kossel, are for 1515 Aluminium, as are the HTA3D printed parts. These will not work with 2020 Aluminium.
  2. There are two (or three – if you include the Transportable, Travelling Kossel version) common variants of the Kossel: Kossel Mini and Kossel XL. All of these variants use the same printed parts – the only difference between them are the lengths of the aluminium extrusions used for the frame, and the carbon rods.
  3. Additional Parts: The kit from BuildA3DPrinter has some additional parts, which are not present in the original BOM:
    1. Home point,
    2. Vertical-Rollers carriage,
    3. Groove mount (for hotend)
    4. Extruder mount


Other Kossel Mods


Here are a few:

Printed Parts for 1515

3D Print STL files

Pre-printed kits

Printed Parts for 2020

3D Print STL files

Pre-printed kits

All of the kits below have a downside, be it a missing extruder, or a flimsy extruder, or no vertical v-roller carriage. However, if the seller is contacted directly, they may be able to help you out.

Aluminium Frame


From RobotDigg,


From RobotDigg,

From AliExpress


From RobotDigg,

  • 2040 or 3030 Alu Vertex for Kossel XXL or XXXL, $71/71/73/81 (2040-Nema300/2040-Nema600/2040/3030 – Takes 2040 horizontals (top) and 2060 horizontals (bottom). For builds larger than 1 meter, using a Nema 23 stepper motor recommended, and there are aluminium vertices that support this size stepper motor.

Kossel 25K

Kossel 25k is a set of brackets, made from sheet aluminium, for large extrusions. From google groups – Metal Kossel 25000 Vertices [final version]

Below is a repost from the previous thread which was getting kind of long. Also thought it was worthwhile to condense some of the information about the current version of the aluminum vertices. (You can read the other thread to see how we got to this point.)
The part we are going to production with is detailed here. Our plan is to offer sets of 12-14 (you only need 12 to build a machine, extra parts may be added to compensate for any deficiencies in the initial production run.) The vertices will be compatible with 15x15mm to 20x60mm aluminum extrusions, though they will also work with 30x60mm (at least for the verticals.) They will be made of 2mm thick 5052 aluminum and (hopefully) have a black anodized finish.  The final price for the packaged sets has not yet been determined, however, it should come in at around US$35 (maybe less.) The variables in initial price are packaging, volume of first order, the costs associated with duties, shipping from the factory to the distribution centers, and incidental expenses.

See also, Mount a Kossel XL. The STL file is available here, 25000_final.STL. On Amazon (US only), Kossel Metal Bracket, $51. See also google groups – Kossel 25000 carriages. Apparently in EU email: wb@neuralcloudcomputing.com, but the domain is dead. I ended up contacting Roland Lock <think3dprint3d@gmail.com>.

Aluminium Lengths

The aluminium required is Misumi HFS3-1515:

Misumi HFS3-1515
Misumi HFS3-1515

or OpenBeam:


From OpenBeam 1515 Extrusion, V2

OpenBeam 1515 Extrusion, V2
OpenBeam 1515 Extrusion, V2

The main problem is trying to source 1515 aluminium in Bangkok. It is quite difficult to find 2020. The larger sizes such as 2525, 3030, 4040 and 5050, etc., are not a problem.

See notes 6 and 7  (at the bottom of the page) for four of the different aluminium extrusion profiles (V and T slot, and I-type and B-type).

From ReprapWiki – Kossel, the lengths of 1515 Aluminium Extrusion (OpenBeam from Builda3dprinter.eu or OpenBeam.de or Misumi HFS3-1515) are as follows,

For the Kossel Mini:

  • 3x 600mm vertical
  • 9x 240 mm horizontal

So, a total length of 1800 + 2160 mm = 3960 mm is required.

Fine, if one 4m length is purchased. However, if it is a set of four one meter lengths then three pieces of one meter can provide the three 600 mm lengths and three of the 240 mm lengths. This leaves six 240 mm lengths, which, after the fourth 1m length has given up four 240 mm lengths, would require and additional 500 (480m) length to provide for the remaining two 240 mm lengths.

For the Kossel XL:

  • 3 x 750 mm vertical
  • 9 x 360 mm horizontal

So, a total length of 2250 + 3240 mm = 5490 mm is required.

For the Travelling Kossel:

  • 3 x 550 mm vertical
  • 9 x 210 mm horizontal

So, a total length of 1650 + 1890 mm = 3540 mm is required.

For the Kossel XXL:

  • 3 x 1000 mm vertical 2040
  • 12 x 500 mm horizontal 2020

If using Robotdigg’s 2040 aluminium corners, for larger frames, then the horizontal frame requirements become:

  • For the top:
    • 3 x 500 mm horizontal 2040, or
    • 6 x 500 mm horizontal 2020
  • For the bottom:
    • 3 x 500 mm horizontal 2060 (fully enclosed), or
    • 3 x 500 mm horizontal 2020 and 3 x 500 mm horizontal 2040 (fully enclosed), or
    • 6 x 500 mm horizontal 2020, (all round gap), or
    • 2 x 500 mm horizontal 2040 and 2 x 500 mm horizontal 2060 (for one gap at front), or
    • 1 x 500 mm horizontal 2040 and 4 x 500 mm horizontal 2060 (for a gap on two sides)

For the Kossel Large:

  • 3 x 1000 mm vertical 2020 (or, preferably, 3 x 1000 mm horizontal 2040)
  • 5 x 355 mm horizontal 2020 and 2 x 355 mm horizontal 2060 (or 9 x 355 mm horizontal 2020)

If using Robotdigg’s 2040 aluminium corners, for larger frames, then the horizontal frame requirements become:

  • For the top:
    • 3 x 355 mm horizontal 2040, or
    • 6 x 355 mm horizontal 2020
  • For the bottom:
    • 3 x 355 mm horizontal 2060 (fully enclosed), or
    • 3 x 355 mm horizontal 2020 and 3 x 355 mm horizontal 2040 (fully enclosed), or
    • 6 x 355 mm horizontal 2020, (all round gap), or
    • 2 x 355 mm horizontal 2040 and 2 x 355 mm horizontal 2060 (for one gap at front), or
    • 1 x 355 mm horizontal 2040 and 4 x 355 mm horizontal 2060 (for a gap on two sides)

Aluminium Extrusion kits on eBay

  • Kossel mini delta 3D printer 20mm x 20mm 4-slot Aluminum Extrusion Cover Kit, US, US $42.95 (THB1,481.34) offer, normally $54.95 + Free (UK/Thailand)
    • L600mm*W20mm*H20mm aluminum profile vertical beam x3
    • L240mm*W20mm*H20mm aluminum profile horizontal beam x9
    • M3*8mm hexagon socket head cap screws x35
    • M3 thread slim T-nuts x35
  • From BuildA3DPrinter nuts and bolts, The kit consists of:
    • 1x M2.5×12
    • 10x M2.5×16 (plus 1 spare)
    • 100x M3x8 (you need about 63 so enough spares)
    • 1x M3x16 (plus 1 spare)
    • 6x M3x20 (plus 2 spare)
    • 12x M3x25 (plus 3 spare)
    • 3x M3x35 (we don’t use it for tensioning but you may choose to do otherwise)
    • 100x M3 Nut (you need most of them)
    • 1x M3 Nyloc nut (plus 1 spare)
    • 100x M3 washer (you need about 60 of them)
    • 12x M4x20 grub screw (plus 3 spare)
    • 1x M5x20
    • 1x M5 Nyloc nut
    • 1x M5 washer

Sourcing the aluminium in Bangkok

From Building a Wilson II in Bangkok, I had some issues locating a supplier for 2020 aluminium.  I found a supplier behind MBK, in the Pathum Wan/Chula area, P.M. Metals & Tools LTD., Part., 163/2 Charoen Mueang Road off Banthat Thong Road (the number 73 bus passes within 50 m of the shop), which had some 2020 extruded aluminium at 750 baht for 6 meters. However the profile of the aluminium was not exactly correct, as it will not accept T-nuts, and uses regular M5 nuts instead, which would be fine but not perfect. The stress of a tightened nut would not be distributed so evenly, and over a lesser area.

They also sell 2525, 3030 and 4040 and 4080, but not 2040.

In the end, I went there and got the lengths cut for a Kossel XL. The owner, Prachak, and his son are very helpful and are interested in 3D printing projects.

Ban Mo was the only place that I found supplying the correct extrusion. One shop (Thai Robo Shop) on the second floor (south end of eastern corridor) of BanMoh Plaza had it at 250 baht a meter, and another, SangTaWan,  in a parallel corridor (North end of Western corridor) for 200 baht a meter (note that this shop has moved, and is on the corner of Ban Mo and Thip Wari Alley. ThaiRoboShop supplies inner brackets, bolts, T-Nuts and washers for 50 baht, but SangTaWan sells them for 45 baht.

Carbon Rods

Outside Diameter (OD) 6 mm, Inside Diameter (ID) 4 mm. However, stronger tubes can be used, on larger builds, Outside Diameter (OD) 7 mm, Inside Diameter (ID) 5 mm, from Upgraded arms for the large delta printer

For the Kossel Mini from Builda3DPrinter, 20 €, much cheaper from 3DPrinterComponents, €17.50:

  • 6 x 180 mm

For the Kossel XL from Builda3DPrinter, 30 €, much cheaper from 3DPrinterComponents, €20.50:

  • 6 x 300 mm

For the Travelling Kossel:

For the Kossel XXL

  • Magnetic rods are 410mm, 475mm or 500mm axis to axis

For the Kossel Large:

  • 6 x 315 mm

Note from the BOM on Tri D Printing the rod lengths are:

  • 180.4 mm – Makes 215 mm rods
  • 253.4 mm – Makes 288 mm rods

The 180.4 mm is good for the Mini, but the 253.4 mm is rather short for the XL. Both sizes are $39.95 assembled, $20.95 for a kit, $11.95 for only the rods

Complete Rod Kits for Kossel Mini:

Complete Rod kit for Rostock:

Complete Rod Kits for Kossel XL:

Carbon tubing:

Kossel Specific Rods:

For information on calculating the rod lengths, see Kossel – The Ratio.

Rod ends

Traxxas 5347 rod ends

These Traxxas 5347 rod ends are commonly used for the push arms

Traxxas 5347 rod ends
Traxxas 5347 rod ends

For the Traxxas rod ends:


  • Material: nylon+metal
  • Color: Black
  • Product size:
    • Length: 22mm
    • Width at ball joint:10mm
  • Typer:M4
  • Compatibility Traxxas 5347

Package Included:

  • 1 bags (12 Rod Ends,12 Pivot Balls)

The distance from end of external end lip to center of ball joint is 17.3 mm, see Note 9, at the bottom of the page.

The Traxxas ball joints are M3. 6 x M3 25 mm bolts are required for the effector.

Tie rod ends

These rod ends are a bit more expensive than the Traxxas, but have a different ball coupling, Tie Rod n Ball Joint Pack Set – 12 Pieces – Kossel – Delta – 3D Printer, £12.99

Tie rod ends
Tie rod ends

Igus rod ends

See Google Groups IGUS ball joints (was Re: Linear Slide Question). For David Crocker’s arm modification. These are expensive, KBLM03 is required for the 3 mm bore.


Other suppliers:

  • One drives – KBLM-03, an absolutely laughable £14.14/13.43/12.72/12.02/11.31/9.90 each for 1/5/20/40/60/100

Grub Screws

Used to join the Traxxas to the carbon rods: M4 x 20 mm


Steel arms

These are not recommended, the rod ends are too large and can bind at the effector, although Sintron dispute this. See Sintron Quality Issues, at the bottom, for further details.

Stainless Steel Diagonal Push Rod
Stainless Steel Diagonal Push Rod

Push Rod Damping Springs

Magnetic Push Rods/Effector/Carriages

See also Magnetic personality

An interesting, yet expensive, Kossel Mini /XL magnetic effector+carriage+ Diagonal push rods f/ V5 V6 Hotend, £85.20/92.90 180/300 mm

Magnetic Effector and Carriages
Magnetic Effector and Carriages

One wonders how effective the magnets work in the effector when hot.

Delta Kossel Rostock magnetic SET 1x Effector, 3x Carriages, 3x rods – MAGNETIC, £75.96 (€90) Comes with complete carriages. Unclear if all aluminium.

Magnetic Full Carriage and Effector Set
Magnetic Full Carriage and Effector Set

Magnetic ball carbon arms

Magnetic Holders

Magnetic Holders
Magnetic Holders

Tapped balls

Drilling Balls
Drilling Balls

Threaded balls

12 mm Ball Screws
12 mm Ball Screws

Complete ball and socket sets

Magnetic cup, ball and screw
Magnetic cup, ball and screw


See Choosing stepper for a delta:

Delta printer have a kinematic very different from Cartesian printers as due to the geometry, while one carriage is in low position, the speed and acceleration of this carriage is nearly three times higher than the effector speed. So, at maximum printable diameter, the stepper shall run three times faster than for a Cartesian printer.

Axis stepper motors (1.8°)

For the Kossel kits supplied by BuildA3DPrinter.eu, the steppers used are Wantai 42BYGHW811 (Link, PDF: Wantai_42BYGHW811)

47.0 N·cm 3.1 V Ø 5 mm 1.8° 48 mm 2.5A 1.8 mH

Cheap Stepper on eBay: 2 phase 60 Stepper motor 1.8° 1.5A 2.7V for Kossel Delta Rostock 3D Printer,  $18.00 (£13.96)

HYBRID stepper motor 42HSC8402-25B
  • Step angle:1.8°
  • Rated voltage: DC 3.0V
  • Number of phase:2
  • Rated current: DC 1.5A
  • rotation direction:A-AB-A-clockwise
  • Resistance per phase:2.0±15%ohm(20℃)
  • Insulation class:B
  • Inductance per phase:4.5±20% mH(1kHz)
  • Rotor inertia:100 g.cm²
  • Holding torque:≥600mN.m
  • Weight: 0.5Kg
  • Dimension:42x 42 x 60mm (without shaft)
  • Length of wire:120cm

I ended up buying Wantai 42BYGHW609, 5X(42BYGHW609 Stepper Motor Laser Grind Foam Plasma Cut Silver black) GX2555, £33.58 + Free. Very cheap, and they recommended on the RepRapWiki, Nema 17 stepper motor. I am not entirely sure what the difference between the 609 and the 811 is… maybe they are not suitable for a Delta printer..? We shall see…

For the Kossel Large: 17HS19-1684S (1.8°)

17HS19-1684S 55 N·cm 2.8 V Ø 5 mm single 1.8° 47 mm 1.68A 2.8mH

Axis stepper motors (0.9°)

For greater precision, you could upgrade to a 0.9° stepper motor. However, 24 V is advisable (in order to give the speed equivalent to that of a 1.8° stepper motor)  and therefore, you would also need a 24 V heater for the hotend, 24 V hotend fan and a 24 V heatbed:

Similar Steppers:

For larger builds, over 1 meter, Nema 23 stepper motors may be used. I found some in Ban Mo, at ThaiRoboShop, for 380 baht with 9.9 kg•cm torque. These can be used with the larger aluminium vertices from RobotDigg, see the section Aluminium Frame, above. See also Do you really need a Nema 23?

Other second hand Nema 17 steppers, from Ban Mo, the shop on the corner, SangTaWan, 435B$:

  • Minebea (PDF link23km_k), It is virtually impossible to find the specifications of these motors, apart from their stepping angle of 1.8°:
    • 23KM-K036-P10V

    • 23KM-K036-P13V
    • 23KM-K036-G9V
    • 23KM-K035-58V
    • 23KM-K379-G2V
    • 23KM-K036-P10V
    • KH56JM2UO14A06/PF2274K530A
    • KH56JM2UO14A05/PF2274K531A

Extruder stepper motor

There is an additional planetary gear box attached to the extruder stepper motor, see Identify the parts, @ @5:05. This gives an incredible torque of  16.2 kg•cm (158.86 N•cm, 224.98 oz•in). See The extraordinary extruder for more details, or 3317_1 – NEMA-17 Bipolar 5.18:1 Planetary Gearbox Stepper – Discontinued. However, this stepper has been replaced by 3325_0 – 42STH38 NEMA-17 Bipolar Stepper with 5.18:1 Gearbox, and costs $40.

On eBay, Extruder Gear Stepper Motor Ratio 5:1 Planetary Gearbox Nema 17 Step Motor New, £20.99 + Free (UK only). Note that it has a 8 mm shaft (and not 5 mm which is the usual shaft diameter of a Nema 17 stepper motor. The stepper motor itself is a 17HS15-1684S-PG5:

17HS19-1684S 55 N·cm 2.8 V Ø 5 mm single 1.8° 47 mm 1.68A 2.8mH

Stepper Anti-Vibration Dampers

Vibration dampers for stepper motors – use the pair of open holes to attach to the motors, use the pair of threaded holes to the frame.

These are very useful as they reduce vibration and hence significantly reduce noise. See BuildA3DPrinter’s videos Identify the Parts at @11:35, and Mounting the motors – #7: Motors at @0:09. Mount the dampers to the motors first, using the open hole (not the threaded hole – these threaded holes are used for mounting to the frame), before mounting to the frame. Use M3 x 6 mm, or M3 x 8 mm with a couple of washers.

In Ban Mo, from the corner shop, SangTaWan, (corner of Ban Mo and Thip Wari Alley) I managed to find dampers for 30 baht a piece, and, in fact, the shop owner discounted them so that I got 4 for 100 baht.

Nema 17 Anti-Vibration damper
Nema 17 Anti-Vibration damper

I actually went back and got twelve more, at the same price. Unfortunately, once I had got home, and paired them up with a Nema 17, it turned out that they were for a Nema 23 – with the bolts being 5 cm apart rather than 3 cm:

Extruder gear

It must be noted that if the stepper motor with the attached planetary gearbox is used, then a bore of 8 mm is required, as the shaft of the gearbox is 8 mm. Worth a read is the Extruder Drive Gear Shootout, which compares ten of the most commonly used extruder gears.

On eBay: 8 mm bore

On eBay:

On eBay: 5 mm bore

Similar to above, but 38T


Cooling fans on each side of the print, see #19 – The first print, @59:55. Or, have a fan attached to the hotend/printhead

Aluminium Effectors

There are three main types of aluminium effector:

The M3 threaded holes are only 8 mm long.

In addition, there is an alternative dual M4 effector for separate hotends, as opposed to the E3D Dual hotend, which has three holes, with the third hole for the wiring.

Some of the cheaper effectors, do not come with a collar.

Dual Effector

From eBay, Compatible with Dual E3D V6:

Dual Effector
Dual Effector

For two independent hotends:

M4 Effector
M4 Dual Effector

Single Effectors

M3 Effector
M3 Effector
Lighter M4 Effector
Lighter M4 Effector

Effector connectors

Fisheye Effector Connector For M3 Aluminum Alloy CNC Fittings For 3D Printer, £1.22/£3.65 (1/4 pcs)

Effector Connector
Effector Connector


If you need both types of collar, it can work out cheaper to buy an effector with a collar already and then just purchase the additional collar separately, rather than an effector without a collar and then buying the two collars.

Of course, if you only need one collar, then, depending on whether the effector that you want has the correct collar or not, getting the collar separately and the effector alone could work out cheaper.

Note: The E3D V5 version has a indent in the collar, the E3D V6 version does not.

From eBay, V5 V6 Heat Aluminum Oxidation for 3D Printer Reprap Kossel, £1.38

Aluminium Rectangular collar

Plastic Effectors

Aluminium Hotend Cube

Kossel Delta Robot Aluminum Cube Fan and hotend mount – RepRap 3D Printer, £14.99, available in blue or black.

Kossel Aluminium Cube
Kossel Aluminium Cube

Effector and Hotend kits

Dual Hotend kit
Dual Hotend kit

V6 Double Extrusion Head With M4 Effector Aluminum Fisheye Deck For 3D Printer, AU $62.38 (£35.70) + Free

These could be considered expensive, when you take into account the cost of the hotend, see the section on Hotends, below.


There are, essentially, three different dimensions that you are looking for, depending on the vertical carriages that you use. The Inner diameter (ID) is defined by the size of the bolt holes on the vertical carriage, the Outer Diameter is defined by the spacing of the wheel mounts, from the extrusion, on the vertical carriage:

  1. The dimensions of the Sintron V-rollers are ID=6mm, OD=22.5mm, width=7mm
  2. The dimensions of the BuildA3DPrinter rollers are ID= 3 mm, OD= 15/15.5 mm, width= 11/12 mm
  3. The STL file’s rollers, which uses ID= 5 mm, OD= 22 (up to 25) mm, width= 7 mm

IMPORTANT NOTE about 5 mm bore rollers: The bearing, in all of these cheaper rollers, is a 625 (5 x 16 x 5 mm), with an axel diameter of 5 mm. However, the printed v-roller carriages are either 6 mm for the Sintron, or 3 mm for the BuildA3DPrinter, so it will be necessary to change the bearing to a 626ZZ (6 x 19 x 6 mm) (696ZZ (6 x 15 x 5 mm)) or 623ZZ (3 x 10 x 4 mm), respectively. However, the inner diameter of the nylon wheel is 16 mm, and therefore none of these bearings will fit correctly – the 696ZZ is closest (at 15 mm) but it is still 1 mm too small. Therefore, these wheels/bearing combination is not suitable. However, a 616zz bearing has the correct dimensions, 6 x 16 x 5 mm. However, removing the 625 bearing is not easy, and damage to the outer surface of the wheel can occur, thereby rending the wheel useless as the smoothness of the wheel is lost and the travel of the wheel becomes jerky, or lumpy.

However, as there are so many 5 mm bore rollers, there must be a vertical carriage that uses M5 bolts… and apparently this does, Carriage Roller for Kossel w/ OpenBuilds 2020 V-Slot Extrusion & Mini V Wheels

Use of spacers

It is possible to use wheels which have 5 mm bearings, with M3 bolts by the use of spacers, aluminium or nylon, assuming that the outer diameter (OD) of the spacer is 5 mm. The width of the two 625zz bearings is 8 mm:



Nylon Rollers

From eBay: 9Pcs 21.5mm * W7mm V-Roller Wheel Mini Kossel Delta 3D Printer 625ZZ 5*21.5*7mm, $14.99 (£11.58) + $19.08 (£14.74) (p + p)


9Pcs 21.5mm Dia * 7mm Roller Wheel

Outer Diameter approx. ∅21.5 (mm)
Width approx. 7 (mm)

Usable with : Alu Extrusion Kit 2020 with the gap width approx. 6.23mm

As above, but cheaper, from China, 12pcs Kossel nylon plastic Wheel with Bearing 625ZZ POM roller wheel 5*21.5*7mm, £4.98.

Even cheaper, in black, 10pcs POM/Rubber Coated Pulley Tire Wheel Arc R Type Ball Bearing, $3.07 (offer, normally $3.49) (£2.40) 5x23x7.5, in white 5x23x7 $5.10 (offer, normally $5.70) (£3.99), in white 5x18x6 $5.01 (offer, normally $5.69) (£3.92)

Also, there is the (19 mm) K800 wheel

Delrin Rollers

Far stronger, but more expensive than nylon, are v-rollers made from Delrin, or POM, see Wikipedia: Polyoxymethylene.

There are three common types of Delrin roller used with 3D printers/CNC:

  1. Mini roller (sometimes called “Single-V”) OD = 15.3 mm
  2. Solid roller/Big roller (sometimes called “Single-V”) OD = 23.9 mm
  3. Dual-V (or V-type) roller OD = 23.9/24.39 mm

There is an additional, more expensive but superior, mini roller type, used by the BuildA3DPrinter Kossel, OD = 15.5 mm.

Lastly, there is the I-type OD = 19 mm

There are also the Sintron Delrin wheels, available separately for $5 + $5 (p +p) for 9 wheels – contact the vendor, sintron_tech_usa.


  • Delrin Wheels
    • OD = 22.5 mm, ID = 14 mm,
    • Width = 6.75 mm (max) / 3 mm (min)
  • Bearings 696ZZ
    • OD = 14 mm, ID = 6 mm ID.
Sintron Delrin Wheels
Sintron Delrin Wheels

There is this supplier, 9Pcs Black 21.5mm * W 7mm V-Roller Wheel 3D Mini Kossel Delta 625ZZ 5*21.5*7mm, US $14.99, Approximately £11.65 + US $19.14 (approx. £14.88) – not cheap at all.

Mini Roller

This mini roller is suitable for the Kossel Vertical carriage, used by BuildA3DPrinter. It is usually supplied with a MR105 bearing (5x10x4 mm), but a 623zz bearing (3x10x4 mm) will also fit in the cavity. Generic Delrin Mini-rollers dimensions for 2020 aluminium:

Delrin V Roller dimensions
Delrin V Roller dimensions
Big wheel

This is a larger version of the mini roller. It is about 10 mm bigger in diameter than the Delrin mini wheel, 24 mm as opposed to 15 mm (although this is fine for the Sintron vertical carriages):

Delrin Dual-V rollers

There is a “Dual-V” (or V-type) version of this wheel (also available in steel!). However, it is about 10 mm bigger in diameter than the Delrin (“Single-V’) mini wheel, 24 mm as opposed to 15 mm (although this is fine for the Sintron vertical carriages):

Dual V wheel dimensions
Dual V wheel dimensions

Note that these wheels are made from POM, but it is listed as Polyformaldehyde.

See, on eBay, 6 mm bore dual-v rollers

However, it is well worth noting that, for these prices (9 x £1.74 = £15.66), it would be cheaper to buy the complete Sintron V-roller kit, Kossel Mini Prime Line Roller Carriage Wheel + 696ZZ Bearing, linear rail MGN12, $14.95 (normally $29.95) (£11.69) (which works out at £1.30 each wheel, plus carriages and bolts)

Other 5 mm ID/bore dual-v rollers

Steel Dual-V

“Custom” v-rollers

There are some other Delrin v-rollers, which have a different format. The printer kit from BuildA3DPrinter.eu, uses “custom” v-rollers which are made from Delrin, see Identify the parts, see @6:58. The instructor clearly states that these are custom made for BuildA3DPrinter kit. This is not true, as they are available on AliExpress!

Delrin V roller
Delrin V roller

However, they are rather expensive, even a bulk purchase from China:

These V rollers are designed to roll in the t-slot of the smallest size commercial aluminum extrusions. The stepped Vee shape allows these rollers to fit into the t-slot of extrusions with widths from 3mm up to 6mm. The flat outer surface means you can also run these on smooth surfaces without the need for rails, such as camera dolly, etc.


  • Incredibly small and lightweight for making the lightest possible linear carriage
  •  Fits IN the t-slot groove of 1515 and 2020 extrusion
  •  Comes with two ABEC3 precision high quality greased deep groove 623 bearings for increased rigidity and resistance to wobble
  •  Overall dimensions: 11mm wide | 15.5mm outer diameter
  • Requires a 3mm bolt or shaft

I-Type slot v-roller

There is yet another roller type, mentioned in Kossel Large, which are Roller Ø 19mm I-Type slot 5, €2.14, from Motedis:

Roller I-Type slot 5
Roller I-Type slot 5

Vertical carriages for 1515

3D Print STL

Vertical carriages for 2020

3D Print STL


Side holes for joints are M3
This set has 3 PCS of aluminum sliders for Mini Kossel that uses MGN12 linear rails.
Each part matches hole pattern on the MGN12 carriage.
Part is compatible with 6mm wide 2mm pitch GT2 belt
(it has matching 2mm spacing ratchet to mount GT2 belt).
Screw pattern is 20x20mm. Use M3 screws to mount pulley to the MGN12 carriage.
Package contents:
3 x Mini Kossel Aluminum Slider with M3 threaded holes for joints.
Much cheaper, 3pcs Aluminum Delta Kossel Mini Carriage Belt Slide M3 Tackle Effector Hammock, £12 (option of 3 or 4 mm rod threads):
Aluminium Carriage
Aluminium Carriage


There are three commonly available printed vertical carriages, see below. However, they all use differing methods to secure the GT2 belt. The Sintron has teeth in the grip, but the GT2 belt is secured not in the vertical carriage. The ABS Kossel has teeth  and the belt is secured in the vertical carriage. The Micromake has no teeth but the GT2 belt is secured in the vertical carriage:

Printed Vertical Carriages
Printed Vertical Carriages

On eBay

Vertical Carriage kit with Delrin rollers
Vertical Carriage kit with Delrin rollers


MGN Dimensions
MGN Dimensions

In Ban Mo, these rails are not cheap:

  • 370 mm for 700 baht (with two carriages) per rail
  • 700 mm for 1900 baht (with one carriage) per rail



This section has been moved, see Hotends


The BuildA3DPrinter has a very good printed extruder, which is Johan’s extruder from his Github: Kossel repo, but it is not available separately. It is designed to work with a stepper fitted with a planetary gear box. Here is another example from Kossel mini 1.75mm Extruder Kai:

Kossel Extruder
Kossel Extruder

However, it is available in this kit: Kossel Mini Delta 3D RepRap Printer Printed Parts kit ABS, Colors Available.

ABS Kossel
ABS Kossel

Standard Bowden extruders

A note about right and left and normal: Right is the same as normal but has a longer lever, with a thumb indentation at the end. Left is the same as right, with the thumb indentation, but the mirror image.

It is unclear, yet unlikely, whether these extruders below will work with the planetary gear box:

3D Printer Remote Aluminum Extruder 1.75mm NEMA 17 RepRap Prusa i3 kossel Mk8, $13.99 (£10.86) (without bracket, $9.99 (£7.76))

Aluminium Extruder
Aluminium Extruder

New 1.75mm Filament Extruder Kit For 3D Printer Kossel Mini Delta Bowden RepRap, $17.62 (£13.67) (on offer, normally $18.55)

Another Aluminium Extruder
Another Aluminium Extruder

Without the bracket, nor pneumatic connector,

Cheapest extruder
Cheapest extruder

Without the bracket, with pneumatic connector,

Without the bracket, with 2 x pneumatic connector,

With bracket, 2 x pneumatic connector,

Extruder and bracket
Extruder and bracket

Universal Feeder

PC Universal MK8 Feed Device f/ Delta Kossel prusa I3 Hbot ultimaker 3D Printer, US $11.80 (£9.15), PC Plastic injection

Universal MK8 Feed Device
Universal MK8 Feed Device

All Metal DIY Reprap Bulldog Extruder Wire Feeder Kit Extruder For 3mm 1.75mm, £45.48 + Free (UK only)

All Metal extruder
All Metal extruder

For the cheaper/cheapest extruders, looking at the costs of the missing additional parts, bracket and pneumatic fitting, separately:

Stepper motor bracket,

Stepper Bracket
Stepper Bracket
Pneumatic connectors

PC4=M6 is used for some hotends, the Kossel printer extruder uses the PC4-M5, the MK8 extruder uses PC4-01, at least the Sintron Kossel kit uses that:

one end is : PC4-01 , and another end is PC4-M6.


PC4-M6 Pneumatic Straight Fitting for 4mm
PC4-M6 Pneumatic Straight Fitting for 4mm

With O-ring,

PC4-M6 Pneumatic Straight Fitting for 4mm with O-ring
PC4-M6 Pneumatic Straight Fitting for 4mm with O-ring




So, the cheapest extruder, 3D Printer MK8 Remote Extruder Aluminum Kit All-metal Frame For Makerbot Reprap, 2.75 + bracket 1.75 = £4.50, plus PC4-M6 = £5.00, but seems to be lacking a few screws, although the toothed gear seems better.

PTFE Tubing

PTFE Connector

XYZ Da Vinci Pro 4mm Push In PTFE Tube Straight Connector Joiner Bowden Extruder, £2.75/4.25 (2/4pcs)


Electrical Connectors

DuPont pins male and female (2 and 4 pins):

Wiring Cables and DuPont connectors

Print bed

The print bed sizes are as follows:

  • Mini – 170 mm
  • XL – 250 mm

Heated Bed

Diameters vary from 330 mm to 220 mm for round, or 170 mm for hexagonal

Round Aluminium


Hexagonal Aluminium

170 mm across, for Kossel Mini

Hexagonal FR4

Hexagonal Heatbed
Hexagonal Heatbed


FR4 Hex Heatbed Dimensions
FR4 Hex Heatbed Dimensions




Rockwool insulation

Hexagonal Rockwool
Hexagonal Rockwool

Glass Plate


From BuildA3DPrinter.eu:

  • 170 mm – €17
  • 250 mm – €25

From RobotDigg, Round Glass 180mm for Kossel, $8

The cheapest glass pates are:


Printing Bed Tape





Aluminium disk

For mini, 170 mm

For XL, 250 mm

Combo bed deal

For Mini, Mini Kossel RepRap 180mm Bed Setup Borosilicate glass, PrintinZ Zebra and Heater, for US $55.00, Approximately £42.32. Consists of:

  • 2 x Glass plate 180 x 3 mm (worth 2 x £10)
  • Aluminium plate 177 x 2 mm (worth £10)
  • Kapton heater, 170 mm (worth £14)
  • PrintinZ bed, 170 x 4 mm (worth $24 £20)

Spool guide

Leveling Sensor

3D Printer Film Leveling Pressure Sensor For Kossel Delta Leveling Base Plate, €11.28 (£9.56) + €3.50 (approx. £2.97)

Leveling Sensor
Leveling Sensor

3D Printer Film Leveling Pressure Sensor For Kossel Delta Leveling Base Plate, €16.26 (£13.78) + Free

GT2 etc.


GT2 Belt


Toothed Gear

20 Teeth 5 mm
16 Teeth 5 mm
20 Teeth 8 mm



  • See section on Bearings, above


Complete Kit


See separate article, Kossel 3D Printer – Fasteners

That’s all folks!


  1. Planetary gear box for the extruder stepper motor, Identify the parts, see @5:05. See also The extraordinary extruder.
  2. Note that the HTA3D kit does not come with the v-roller carriage. See these examples:
    1. Kossel carriage truck for 2020 extrusion and V rollers;
    2. Kossel Roller Carriage (only suitable for 1515 aluminium)
    3. Other examples: Kossel mini v roller
    4. Carriage Roller for Kossel w/ OpenBuilds 2020 V-Slot Extrusion & Mini V Wheels
  3. From Will standard M5 T-slot nuts fit these different 2020 aluminium extrusions?, the openbuilds v-slot is another alternative extruded aluminium.
  4. Note Johan’s offer of free printed parts, mentioned on Github: jcrocholl/kossel.
  5. For a 2020 Kossel, see Kossel Frame 2020
  6. Compare T-slot and V-slot, see T SLOT ROLLER WHEEL

    T-slot and V-slot
    T-slot and V-slot
  7. I-type and B-type, from Motedis – Slot Profiles:B-Type Slot 6andI-Type Slot 5
  8. For larger printers, see
  9. The distance from end of external end lip to center of ball joint is 17.3 mm, based on TriDPrinting BOM:

    Given that,

    Carbon rod length (180.4 mm) + 2 x Traxxas joint length = Total rod length (215 mm)


    Traxxas joint length = (Total rod length – Carbon Rod length) / 2

    Traxxas joint length = (215 – 180.4)/2 = 34.6/2 = 17.3 mm

  10. See on hackaday – Kossel Xl – A delta 3d printer, using 2020 vslot extrusion

Build videos

See Kossel construction videos.

Vertical movement

There are three methods of vertical movement:

  1. Pulley – Using the aluminium extrusion and a roller carriage
  2. Axis – Using rods and linear bearings
  3. Linear –  Using MGN-12 rails

From converting the FLSUN’s carriage into a MicroMake D1 type:

Pulley, Axis and Linear vertical carriages
Pulley, Axis and Linear vertical carriages

Sintron Quality Issues

Here are a few threads that do not recommend the Sintron build – FolgerTech appears to be a better choice.

Thread #1

From this review, 2 thoughts on “[Sintron] 3D Printer Kossel Mini Prime Line Roller Carriage Wheel + 696ZZ Bearing, Replace Linear Rail MGN12 for RepRap Rostock Delta Kossel Mini”:

Printed with very ridged, brittle, plastic, does not fit the rail snugly even at it’s smallest setting. I assembled one carriage to see how it would do replacing my home-printed carriages. It was far too big; so loose that the rollers don’t even roll, it just falls straight down. I then left it on the bench for a week until I had time to play with it again. Came back.. and it cracked in three places. Between the slop in the hole position, and the brittle plastic, it was too much…

Thread #2

A long list of complaints in this tale, Sintron Delta Build – Buyer Beware!

  • As with most things, You get what you pay for – the plastic parts leave a bit to be desired. they range in quality from excellent (left) to unusable (right) …
  • but the thing that bothers me the most is they are printed in PLA… Ok, so new printed parts are in order.
  • Got all of the frame corners re-printed with no major problems. started putting in the screws & T-nuts to start assembly… test fit a piece of the 2020 to one of the frame corners and our first problem showed up… the T-nuts were bottoming out against the plastic and were no where near being tight on the 2020… so, had to modify each corner piece to reduce the amount of plastic where the T-nuts fit…
  • We are having to reprint the wheel carriages and the belt/arm assemblies, as well as the effector plate – apparently there is no quality control when it comes to the plastic bits. One of the belt holders had obviously shifted during print, making it useless. another had bad sagging of/around the arm mounts. Cant fit the locking nuts in the holes on the effector plate for mounting the arms… and the list goes on.


  • The build instructions are a bit of a joke… plagerized from another kit retailer (Blomker Industries). They cut out a lot of stuff, and changed only what they absolutely had to. There is nothing in the instructions about the heated bed, or about hooking up the LCD screen it came with.
  • And here is the best part – they have completely blocked being able to print the instructions! no printing, no copying, nothing but viewing them on your computer screen, and you have to have a password to do that!
  • The instructions for this thing are basically useless. As I noted before, they were plagiarized from Blomker Industries, with major sections cut out completely. The sections that replaced the cut parts (different assemblies) are little more than “gather these parts” and “assemble them” with pictures of the parts needed, and the fully assembled parts – no direction on what to assemble in what order… roll you basically have to make a semi-educated guess as to what needs to be done in what order.

STL files

  • Had emailed Sintron to get the software/firmware bundle and build instructions – got those in no time. Asked for the .stl files for the parts, and they happily obliged – so far so good with customer service…
  • the zip file we were given for the stl files? yeah… only parts out of that we can use were the upper & lower frame parts… no other parts actually in this kit are included in that file, everything else is different… (the file is the Kossel 2020 master originally from github – found it while looking for stl’s for the other parts we need. Thank goodness for thingiverse!)

Steel rods – the ends are so large that they bind

  • got the carriages reprinted and assembled, and a new effector piece printed up… go to assemble the rods to the effector and gee, isn’t that interesting – the huge rod ends they shipped with this thing bind up… (even without the washers next to the plastic they still bind)
  • and, they don’t fit the other end either…

Washers for the rollers

  • Got the effector assembly mounted on the frame and found that the carriages are rubbing ever so slightly on the frame rails… a washer between the carriage and wheel solved that problem… (no, washers were not provided in the kit for this)

Effector/Hotend mount

  • need to modify the effector & find another hotend mount/clamp (and/or modify it to fit right), and probably reprint the probe mount as well.

Stop mounts

  • Have already hunted down and printed up some new end stop mounts for it. What they provided was a joke – basically 2 layer thick pads to keep the circuit board from shorting out against the frame – not a “mount” at all.

Power supply/Extruder/firmware issues from another user

  • auto leveling hooked up (but not working due to a firmware issue), and upgraded to traxxas rod ends. Then I realized the extruder was backwards in the firmware. There seems to be no way of fixing it other than editing the firmware itself. Somebody else bought the printer and sintron refuses to send me anything since I have not purchased a printer myself. I am currently lost in editing the delta printer version of marlin off of github. Does anybody have the stock configuration.h?
    Oh and the stock power supply is crap. Once I put any kind of current draw on it, it stays at 9v, even if I unplug everything. The heated bed never got to 120c because I canceled it after sitting at 70c for 5 minutes.
  • I had to change the Invert_E setting in marlin to true


I finally got my printer running! After about 3 weeks and at least 20 hours of work, I got my sintron kit to run the way it’s supposed to:

Unfortunately, it is nearly impossible to get it running with just stock parts. Here is what you need:
– washer/spacers for the wheels so the sliders don’t rub
– a newer version of marlin. Use the config from the sintron firmware to fill out a new one. I used https://github.com/RichCattell/Marlin  Which is built specifically for deltas
– Either a working auto level probe, or different bed mounts that allow you to adjust it manually. The stock version of marlin always crashed into the bed or would not work in some other way.
-turn down “duty cycle” for the bed in the firmware, otherwise the polyfuse overheats. Even with the 30amp power supply I am using.
– the switch to change from 220 to 110v is inside the power supply. It took me a while to figure out why the voltage was at 9v, but then I found the switch.
– READ AT LEAST MOST of the reprap.org forum topic on the sintron kossel. It is extremely useful.

I also made these mods:
– (fake) e3d Volcano for $8
– e3d v6 clone heatsink and throat (so I can print polycarbonate), still in the mail
– fan mount that also blows on print. Greatly increases the quality of PLA parts. Mine doesn’t fit (see pictures) because the spacing isn’t right on the heatsink/throat
– replaced the z probe Allen key with an inductive sensor from aliexpress for $2
– geared extruder. The stock direct drive would kink ABS filament and stop constantly while I was using the stock e3d v5, and it didn’t run the volcano at all. Http://www.thingiverse.com/thing:1185662
– Ramps & LCD case (yet to be printed at the time of the writing of this article)
– In the video above, I am printing a new spool holder.

I am using Repetierhost Host with Slic3r. I can share config files if needed. Feel free to ask any questions!

Another user

I bought this kit in November last year and still trying to get it to work. Had dodgy RAMPS board and defective thermistor on extruder. Managed to break one of the main printed junctions at the bottom while putting the frame together that’s when I discovered all parts are made from PLA (what would it have cost them to make it in ABS, a few cents more?) was able to glue it back together with epoxy but one day might reprint the whole thing myself in ABS. Fan housing was missing from the kit. Could not find website that showed assembly instructions, mostly I just used pictures from their ebay shop. Asked Sintron about instructions for the fitting of the Z probe (so what do you do with 2 safety pins?) and they replied that the instructions were on page 72. Page 72 of what? They could not tell me and used the old “me no speak English” trick. For wiring the RAMPS they referred me to a website with diagram that was for totally different board. I downloaded the firmware and installed after many difficulties, one being that it instructs the user to replace the config.h file and config.adv with another version from a directory that downloads with it. NO! Sintron says not to do this, so why could they not just delete this information and save days of wasted time while following erroneous information?

So now I have semi functional printer, extruder and hot bed work, motors work, end stops have power but no functionality. Dived into the firmware again and on close inspection found command lines incomplete regarding max end stop inverting. So now end stops will stop motors but!!!!

I have a notion that all axis should rise, hit end stops to set the height above the bed, maybe wrong about this, as there are no instructions for the setup its hard to tell. Anyway only the Z axis works on the end stop and shut off other axis so I can’t home the printer; anyone out there knows where I can find information on the homing and calibration of this printer?
  Think I just answered my own question, check out the following website.
http://www.think3dprint3d.com/3D-Printer-Kits/ go to Kossel Mini and then Documentation tab. Very detailed description of Z probe setup and calibration of Delta printer, not specifically for the Sintron but close enough. Also used this site to put the thing together plenty of good images and useful information.

Associated downloads from Github: gpfwestie/kossel_2020_sintron – Includes Marlin and STL files

Thread #3

A very long and informative thread can befound on the RepRap forums: Ebay SINTRON Kossel Mini full kit.

On page 2, there is a reply from Sintron that disputes the issues with the steel rod ends. The reply also contains many useful links, although the link to the PDF is broken. However, as the Sintron guide is a rip off of the Blomker Industries guide, here is that PDF from link to RobotDigg (Kossel Mini Build Guide By BLOMKER INDUSTRIES)

Other threads


See Kossel Guides and Documentation

One thought on “Kossel 3D Printer”

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