Arcol blog Just another RepRap weblog


New: Grooved 608 bearings

This is the new 608 grooved bearing:

It has an awesome half circle groove which is a perfect fit for the filament.
I use a normal 608 bearing, so it fits to a Wade style filament pusher exactly, like
the Greg's accessible extruder body (thing:8252). Here is a closeup picture:

Here is how the filament would look like on the bearing:

And also a picture with the hyena:

Oh wait, I can do a better photo, to see from the front (notice the match for frame of reference):

Why is it an awesome thing to have?

  • It prevents filament twisting
  • It is a guide in itself, Accessible Greg's extruder, needs one I believe, at least for me its needed. (accidents happen:-(

Im collecting ideas here. Im recently trying out many methods to raise funds to manufacture the newest gadget for 3D printing world:)

Well, this small improvement may not deserve a full campaign, like the awesome mini hyena, but still what do you think what would be an adequate price for it?

If you have a thought about pricing, or more what price is it worth for you, just put it in the comment. If we can agree on a sane pricing, I will list at that price on the webshop:)

Lets do it folks!

Some of you were wondering how much flesh rest at the bottom of the groove.
So I destroyed one for ya:)

And here is a better view from the front:

Im not worried about wall thickness here, it is imho pretty strong still.
If you have any other question just shoot it in the comments:)

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!


Another planet update (article updated)

I have been working on the planet furiously during the whole week.


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?




Filed under: Uncategorized No Comments

Blender broke – Epilogue

My article titled "Blender broke" drew more media attention, than anything I've written lately. This is strange, as much cooler things have been happening around me:) Many sites picked it up.

I later read on a forum (I've forgotten which one), that the printed replacement part will break as it could not possibly be as strong as the original one. That did had some truth to it...



When a compiler reach the state, when it can compiles itself, it's called self-hosting.
My Hot-end v3.0 reached that state, and more:-)

30Oct/10Off Hotend v3.0 dummy model

This is a dummy model of Hot-end v3.0 to get a feeling of the actual size. A real hot-end cant be printed using plastic:)

28Oct/10Off Hotend v3.0

This is a really big announcement.:-) The new hot-end has been born, and rocks!