Arcol blog Just another RepRap weblog


Chrome beauty

Grab one here.

The chrome family:

Here is how the normal mini hyena v2.1 with 8mm bore looks like:

Here is how the mini hyena v2.1 looks chrome plated:

I think the normal hyena looks the most beautiful when chrome plated:

It is really shiny, it is almost like having a brand new bike:)

Here is a comparison photo between the mini hyenas:


Summary of 2012, 220% steam ahead

What a year. Read and remember the biggest moments of 2012.

And at the end get to know of a completely new product, the best way to finish a year.

Lets greet the new family member, the mini-hyena v2.0 and also regular hyena v2.0!

Achievements in 2012

Just a quick recap before we advance to the next big thing:) hotend v4 — 2012 January

Although the initial version of the v4 hotend went live at the end of 2011, many later improvements came this year. So it is a really 2012 product. Grab one here. hyena v1.0 — 2012 April

I started with v1.0, do you remember?:

M8 nut with M3 grubscrew — 2012 April


When a simple nylock M8 nut is not enough, and you need more torque.
Documentation here. Available here. hotend v4.0.5 — 2012 May

Bugfix release over v4.0. Announcement here.

Grooved 608 bearing — 2012 May

Tiny, but useful improvement. Original announcement here. mini hyena v1.0 — 2012 June


Discovering the need a reliable drive gear for direct drive mechanism, I launched the mini hyena campaign.

I gathered many feedbacks from this campaign, which helped to redesign the whole hyena family. See at the end of this article:) hotend v4.1.1 — 2012 October


I improved v4.0.5 more, and came out with v4.1.1:
It is not only bugfix (set screw), but also a real improvement (aluminium mounting) and aesthetic (black tubing) over v4.0.5 design.
Grab one here. hyena v1.1 — 2012 October


It is basically a usability improvement. Now you can counter-tighten with a 6mm wrench instead of a pliers.
For announcement, read here.
Grab one here.

Spring kit — 2012 November


Original announcement here. Grab one here.

Maglev fans — 2012 November


Maglev fans move more air with less noise; a small but nice improvement.
It is available for sale with the complete extruder (see next point).

Complete extruder — 2012 December


Original announcement here. Grab one here.

The Hyena family v2

The campaign helped me get the manufacturing done and gather much feedback.
Which kickstarted the design of v1's successor!

Asymmetric tooth profile - Hyena v2

To come up with this tooth profile it had taken countless hours and numerous versions.

Did you think the hyena was a great product? Then you'll think v2 is the best product ever!

The v2 outperforms v1 by 220%. That means at a given force where v1 has already slipped and chewed up your filament, v2 is still pushing it through happily!



For the tech-savvy out there, here is the drawing:

Unified size

One of the main discoveries from the campaign was
that the four different sizes did more confusion than good.

The conclusion is to make one size with either a 5mm or 8mm bore.
It makes everyone's life easier and one size fits all!

Here is a picture to demonstrate this handy property:

Regular hyena adjusted — Hyena v2.0

This news itself would deserve a separate article, as it is a huge milestone.
For v1.0 announcement, read here, and for v1.1 read here.


The shorter, the better

You don't need worry about the length of your motor shaft. Or particular extruder design,
because the mini hyena was designed to the shortest length possible: 10mm!

One size fits all

A picture worth a thousand words:)


Mini hyena fits on either 5mm or 8mm motor shafts.

Final look

When the extruder is properly set up the hyena accumulates absolutely no plastic chips over time.

Here is a photo after two weeks of continous printing:

If there are some chips inside, clean the Hyena with a needle not a file.
Never use heat especially not a blowtorch.

Printing achievements

I should compile an another article, where we are currently quality-wise, since I teamed up with a professional graphic artist (hey QNLaca!:)).

Until that article, here is a photo for the impatients:

Hall of fame

People, who made the mini hyena and also the v2 development possible:

  • Anonymous
  • dazed.dnc
  • Anonymous
  • atntias
  • Sefi1
  • fdefoy
  • harmonicity
  • hewball
  • houde.jeff
  • Anonymous
  • whosawhatsis
  • Intrinsicallysublime
  • bjoern5
  • contribute1334329857
  • cjmekeel
  • ckaosatom
  • scott.a.maher
  • wat_willy
  • raldrich
  • nop.head
  • device2003-kst
  • RobPovey
  • repraphd
  • justin.hawkins
  • Anonymous
  • contribute1338394611
  • vastempty
  • contribute1338413084
  • Anonymous
  • Inc0me
  • gary.s.hodgson
  • Anonymous
  • Anonymous
  • MattS
  • hoani.cross
  • boman22
  • lincomatic
  • Anonymous
  • colin22
  • m.feherpataky
  • DerekAnderson1
  • proto.user
  • Anonymous
  • SteveKelly
  • contribute1338109472
  • Pazu1978
  • AlessandroRanellucci
  • reprapdiscount
  • paranya2
  • Anonymous
  • Anonymous
  • labmat
  • maxinux
  • kurtis.burr
  • Anonymous
  • maik1
  • clem.taylor
  • Anonymous
  • Anonymous
  • JordanRoss
  • logxen
  • Anonymous
  • Anonymous
  • logxen
  • jax1000
  • reprapdiscount

It's Party-time! See you guys in 2013!:) Can't wait to show you my latest stuffs!:)
I change slightly the commenting policy. I will close the commenting after a week of the date of publishing to prevent spams leaking through.

But in all occasion, please prefer the mailing list.

After the above deadline, any further discussion can only happen on the mailing list, in this thread.


Recommended extruder setup


Grab the complete setup here.

Many people ask me what setup I am using with the v4 hotend,
or what setup I recommend for it.

I bit the bullet, and I wrote this detailed article.

I am always trying to push the envelop of 3D printing, therefore my machine
is evolving all the time, so you can expect more articles in the future:)

The extruder shown here will also be available as a kit through the website.

This recommendation is for 2012 december, although it could have been built since around 2012 march.

Partlist (with pictures) hotend v4.1.1:

Go grab one! or Grab the complete setup! hyena v1.1:

Go grab one! or Grab the complete setup!

M8 nut with M3 grubscrew:

Go grab one! or Grab the complete setup! spring kit:

Go grab one! or Grab the complete setup!

40mm fan:
Are you wondering why is a cap there?: Maglev carriage fan

Wade's accessible extruder body:

Carriage with 2 fan holders:

Satchet of nuts and bolts:

608 bearings and linear bearings (LM08UU):

Just to see it in perspective:)

Downloading the .stl file of the RP parts

All of the RP parts, are from thingiverse.
However I have modified almost all of them. I will publish one .stl file per
week on thingiverse, referring back to the original thing and its author.

Assembly of the carriage

Here is the carriage one more time:

The linear bearings goes in there:

The two fans on the sides, and it looks like this when mounted on a machine:
(Note: There is one bar clamp missing from the above picture)

The modell of this print is available on thingiverse, as thing:39923. It is basically a touchup of thing:15534, which is based on thing:9869.


This is the idler of the Wade extruder pusher:

It has an integrated guide, so you dont need the grooved 608 bearing,
to guide the filament, its mere cost saving.
You can still have the grooved 608 bearing, it does not make things worse, this idler just duplicates the grooved 608 bearing feature.

The modell of this print is available on thingiverse, as thing:39933. It is basically a touchup of thing:17030 and thing:6703.

I have RP parts available in three different colors: white, green and black.
Here is a comparison between green and white print:


Here is the gears I use:

You may be wondering why I am not using herringbone gears.
Herringbone gears run a little quiter, and have a tiny bit less backlash.
Also they can handle higher torque.

However it does not affect print quality.
The filament has a backlash due to its inertia, and we compensate
for backlash anyway. It has the same number of teeth, so no additional
resolution either (not that we need it).

But the main reason is that it is more troublesome to print out, for no real
advantage, so I kept the traditional spur gears. You can print a
herringbone if you wish as an upgrade.

Wade pusher (extruder upper body)

Here we go:

It is a modified Accessible Wade extruder, mainly the holes were adjusted.
It is more accurate and compatible with
v4 hotend.

Here is how the gears, idler and wade upper body will come together:

The complete setup

The complete extruder assembled with carriage. Everything mounted:

You can see the setup is standing on two M8 nuts, so the
hotend is lower by just enough distance then the two fans.
It is optimised for the minimum height, so you have the
maximum printing height possible*.

Here are some more pictures, it is kind of rotating:)


You could have build this extruder setup from about february of this year (2012).
If someone would have published this extruder setup back in time, it
would have saved me some unnecessary circles.
So I hope you (dear Reader) find this article equally useful,
what I would have found it, if it was existed back then.

Printing quality

If you want to check what is possible
with our v4
hotend in regard of printing quality, or you want a trouble free
extruder setup, then go get one!

As a remainder, here it is the wade pusher printed in white:
(the white is the easiest to photograph, every irregularities are shown)

Im fairly happy with the overall printing quality, you can see it as
our current state of the art at 0.3mm layer height.

No worries, even finer layer height is possible, so it is not the
limit of what v4 is capable of.


Grab the complete setup here.

I think Im able to print one full set per week, and for start I have
3 full sets. I know it is limited, but it is not intended for general
public, just for the quality enthusiastic and those who want
a working printer first and a DIY machine second.

I have some leftover pictures, which would be too bad to miss out:)

And even moar:

I change slightly the commenting policy. I will close the commenting after a week of the date of publishing to prevent spams leaking through.

But in all occasion, please prefer the mailing list.

After the above deadline, any further discussion can only happen on the mailing list, in this thread.


Maglev carriage fan

Why do you need a fan?

As many of you may know, I have been using a double carriage fan (modified thing:9869) for my printer.

If only the hotend needed the air movement,
a single carriage fan would suffice, yet I get better results with double carriage fan.

So first and foremost the print itself needs the fan.

Buying fans for the carriage

Choosing the right fan is not easy. The ideal fan must be able to be driven directly from a PWM output of the RAMPS.

Many fans are not capable of be driven from a PWM output,
so it's mostly a hit and miss when buying small fans.

Why is a MagLev fan cool?

Well, the magnetic levitation itself is cool:) Also it is more efficient per watt (has more air blow power) than a ball bearing or bushing fan.
In my case the ball bearing fan can blow a lit match from 14 cm away, while the MagLev fan can blow it out from 41 cm(!) away.
So roughly 3 times more blowing power.

What to do if the fan is not able to be driven from PWM output?

Modify it like this:

I discovered my Maglev fans are not able to be driven from PWM output, they only work
with M104 S255, and not any value from 0-254.
Issuing a command less than S255 makes a strange pitch noise instead of turning the fan.

So I started experimenting, and I figured that I only need to add a small capacitor (any electrolite type capacitor works) between 4.7 uF and 100 uF.
(YMMV and also warning: some type of fans does not rotate even with this modification)

Also watch out for the polarity, here there is a pic showing how I modified my two maglev fans:


I think the capacitor is small enough not to destroy the aesthetic looks of things:

An example of these small fans on the carriage:

(note the superbright yellowish green clamp in the background:)

I closed down the commenting on this webpage due to the enormous number of penis enlargement suggestions.

If you have any thoughts to share about this article, please discuss it on's mailing list,
in this thread.

30Oct/12Off hotend v4.1.1.


For previous announcement please read here:

The v4.1.1 version

Im really proud to announce hotend v4.1.1:

In a nutshell:
- v4.1. - aluminium mounting plate (that also means integrated setscrew in the heatsink)
- v4.1.1 - firesleeve

Aluminium mounting plate (v4.1.)

I replaced the wood mounting plate with an aluminium one.

Just to recall here is how the v4.0.5 looked like:

Here is the v4.1:

I also added an M3 setscrew, to fix the heatsink to the mounting plate
(prevent rotating the whole hotend at high speed).

Also here is how the hotend looks after 6 months of printing:

So the firecement is quite good solution, once it is applied.

Firesleeve added (v4.1.1)

To prevent skin burn, protect heater block against fan blow, and last but not least looks awesome:

Machine compatibility

This hotend is designed for reprap machines (or compatible).
However I had success reports from customers using in 24VDC system, like R2C2 electronics (you need different resistor, so definietly say it before purchase).

I would be really interested how others have mounted or adapted this hotend for their machine,
like or

If you happen to have a machine like the above, and you want assistance,
just drop me an email through preorder(at-arcoldothu.

Go grab one:

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If you have any thoughts to share about this article, please discuss it on's mailing list,
in this thread.


Arcol Hyena v1.1

Available at:

History (v1.0)

For previous v1.0 announcement, read here:
and here:

V1.1 update

This is a minor, but really handy upgrade to hyena.

At one end it has 6mm flats for wrenches. So no more pliers to holding while putting the big gear onto the shaft.

This is how it should be mounted (flat end is the opposite one from big gear):

Here is a closeup of the two flat sides:

Here is how you should put the big gear onto the hyena:

Also here it is mounted on the extruder pusher:

(Note the M8 nut with M3 grubscrew! It is *really* useful)

M8 nut with M3 grubscrew:

I closed down the commenting on this webpage due to the enormous number of penis enlargement suggestions.

If you have any thoughts to share about this article, please discuss it on's mailing list,
in this thread.


IKEA drawer

Last December I was approached by a friend to do a joint build on a better printer.

I took them up on the deal, because I had an IKEA drawer, where the plastic rail guide had broken, and I was unable to print a replacement part with either of my 3D printers.

I think it is fairly reasonable deciding to build a whole new 3D
printer to repair a piece of furniture which only cost 18EUR originally.

Here is the furniture in question:

We set many goals for our ultimate finished machine,
but the first milestone was to be able to print out this replacement

This model is an excellent stress test, because:
1. it is 200mm long, so with the pads it only fits diagonally on the heated print platform
2. has thin walls
3. well calibrated bridging is necessary
4. retraction is really critical (the small cylinders at the top)
5. relatively fast to print
6. it is big only in one direction, so wants to curl up enormously
7. perfectly levelled bed is necessary. PCB alone does not work.
8. we wanted to print it with ABS plastic (the more difficult one)

Here are some pics to back up the above claims.
It fits only diagonally onto the heated print bed (point 1.)

Bridging is necessary, and has thin walls, so only two filament width.
(point 2. and 3.)

Retraction is really critical (point 4.)

And also another cylinder at the top of the model:

No curling occured (point 6.)

And as a bonus I compiled a calibration object, which is even faster to print:

This model was successfully printed on 5 of March, and here it is installed:

And it has not broken since then, so holding up fairly well
(5 months already!), and we use it daily.

One last photo to show the drawer in action:)

I also published both models on thingiverse, as thing:31115.
Maybe others will find them equally useful.

Technical infos:
1. The model was printed on March 5 using slic3r 0.7.0.
2. We used a 0.5mm v4.0.1 hotend at the time. (currently 4.1.1 is on the sale)
3. Red ABS from reprapsource.

The slic3r config.ini

Layer H 0.4mm
E multi 1
bottom_layer_speed_ratio = 0.3
bridge_flow_ratio = 1.4
bridge_speed = 30
duplicate_distance = 6
duplicate_x = 1
duplicate_y = 1
end_gcode = M104 S0 ; turn off temperature\nG28 X0 ; home X axis\nM84 ; disable motors\nM107 ; Fan off
extrusion_axis = E
extrusion_multiplier = 1
extrusion_width_ratio = 0
filament_diameter = 2.95
fill_angle = 0
fill_density = 0.3
fill_pattern = rectilinear
first_layer_height_ratio = 1
g0 = 0
gcode_arcs = 0
gcode_comments = 0
infill_every_layers = 1
infill_speed = 50
layer_height = 0.4
nozzle_diameter = 0.5
output_filename_format = [input_filename_base].gcode
perimeter_speed = 40
perimeters = 3
print_center = 85,65
retract_before_travel = 2
retract_length = 1
retract_lift = 0
retract_restart_extra = 0
retract_speed = 6
rotate = 45
scale = 1
skirt_distance = 6
skirt_height = 1
skirts = 1
small_perimeter_speed = 25
solid_fill_pattern = rectilinear
solid_infill_speed = 50
solid_layers = 3
start_gcode = G28 ; home all axes\nM106 S150 ; Fan on
temperature = 248
travel_speed = 120
use_relative_e_distances = 0
z_offset = -0.2


I closed down the commenting on this webpage due to the enormous number of penis enlargement suggestions.

If you have any thoughts to share about this article, please discuss it on's mailing list, in this thread.

14May/12Off hotend v4.0.5 v4.0 hot-end for 3.0mm filament (works also for 1.75mm filament too).

It has been a long time since I announced v3.0.

The new features:

  • - Hot-zone is completely metal.
  • - high temp extrusion should be possible, like pp, hdpe, plexi, polycarbonate, nylon (hopefully, this will be confirmed within a month)
  • - shorter, more compact, a comparison photo between v3.0 and v4.0:
  • - easier to assemble
  • - reworked nozzle
  • - laping for wrenches on nozzle, on stainless steel, heatsink
  • - built for easy maintenance
  • - self cleaning (you can remove the hardened plastic using two wrenches:)
  • - built with dual extruder in mind
  • - mounting compatibility for the average/stock reprap hotends
  • - 100k thermistor (which seems to be a more common preference)

For assembly instructions please read here:

Regressions/future adaptations:
Dropped compatibility for Rapman, Makerbot. A new mounting needs to be designed for these machines.
For rapman a 200k thermistor also needs to be sourced to be electrically compatible.


Hobbed bar, hyena v1.0

This is my take of a new hobbed bolt replacement :)

I call it the hyena, because hyenas have the strongest jaw of all mammals.
All teeth are cut individually:

Here is a comparison photo with one of my hobbed bolts:

The brass one is the new version:)
You mount it with a M8 nylock nut, so the width of your extruder does not matter.

Key advantage over the old version

  • It's machined from straight, round brass stock. Regular bolts often have large tolerances and are not entirely straight. The hyena is guaranteed to be straight.
  • Each tooth is individually machines, so there is no "orphan tooth". An orphan tooth is an incompletely cut tooth that occurs during hobbed bolt production with a tap, because the teeth of the tap do not match the diameter of the bolt while cutting. This is a problems because it's the spot where filament begins to slip. It tends to bite a small piece of plastic off the filament as it does not reach deep enough to grip. The next (normal) tooth continues eating into the filament, resulting a complete filament strip, and no printing. The hyena prevents this by making sure every tooth grips by the same amount.

Installing on a Wade style extruder

Some pictures, from the top:

Also when opened (please note the washers around the bearings!):

(Also take note the really useful and special M8 nut. It will be the subject of an another announcement:)

Im a technical guy, any drawings?

Here it is:

Enough talk, I want one!


Guest article: Tiny’s first experience with Hotend v3.0

It was announced as "really big", but is the Hot-end v3.0 is that great?