The Pitan Geared Extruder

02 January 2022
_The Pitan is still the lightest and most compact 3d printed Geared Extruder on the net.
_Both my extruders are still going strong after 5 years. In the spring of 2020, the printer worked nonstop and without issues for 2 months printing hundreds of face shields.

22 January 2020
_This has become the most popular among the easy-to-print, lightweight geared extruders on Thingiverse.
_Both my extruders are still working after close to 3 years, printing 18h a week on average.
_The latest version has some small updates, including Tehmillhouse suggestion regarding the small gear (It goes in teeth side first, everything else gets assembled the same way)

06 October 18
_Had both of mine printed in PLA and still going strong after close to 1.5 years of almost daily printing.
_Just make sure the gears are aligned well
_Also, don't use a lot of idler tension. If your MK8 skips you most likely trying to squeeze too much plastic for that particular speed/temperature/nozzle combo.

03 June '18
_I've been using two of them for a year now and never had any issues.
_If you are looking for an easy way to source the parts, dbgeorge now has hardware kits for sale. https://www.thingiverse.com/dbgeorge/about

31 Jan '18
_Fusion files included. They are a mess sorry!
_Corrected the spring size to 6mm OD, 12-15mm length and 0.8-1mm wire thickness

11 Jan '18
_Updated to v1.1 with smaller 695zz bearings (there are smaller 5mm ID bearings out there but they will not last long), smaller bolts and a lighter, more compact body. Using two mirrored Pitans, direct to E3D v6, we can have the nozzles as close as 22.8mm. Mirrored files are included

The E3D Titan is arguably the lightest end smaller standalone Geared Extruder you can buy.

The Pitan is a cheap and easy-to-print geared extruder inspired by the Titan.

_With no discernable performance differences between them, the Pitan has the same 3:1 gear reduction, the same footprint and overall size, easy-to-see/clean drive gear, supported path for 1.75mm and 3mm filaments and it can be used with any Titan mount, bowden or direct drive. The filament feed path is on the idler arm and just as easy to load as the original Titan and It has virtually the same number of parts.

Couple of recommendations:

_I strongly recommend the Mk8 Hobb-Goblin sold by E3D https://tinyurl.com/2382n7ve They are £4 but you will get almost double the pushing force of a clone Mk8 (see Troubleshooting below )

_Also, get a good stainless steel M5 bolt with a partial thread. It will all but eliminate the wobbling you get from a cheap, out-of-spec bolt.

BOM:

1x Nema17 12.7N-cm stepper motor
1x M5x35mm Hex Head Bolt
1x M5 Nylon Nut
1x M5 Washer OR a just print one
1x 11mm Mk8 Drive Gear - Recommended E3D https://tinyurl.com/2382n7ve
3x M3x30mm Hex Socket Bolts
1x M3x15mm Hex Socket Bolt
1x M3 Nut
1x M3x10mm Bolt OR 1x 3x10mm Screw for the Idler
1x M4x10mm Bolt (Hex Socket or Button Head) OR E3d Thumbscrew
1x M4 Nut
1x 6x15x0.8mm Spring - eBay https://tinyurl.com/4xt8p8ju
2x 695zz Bearings
1x 623zz Bearing
And either
1x Bowden plastic coupling - like this one from https://tinyurl.com/4mam95kb
Or
1x Bowden Groove Mount

A typical Pitan has the following printed parts:

_Body
_Cover
_Idler Lever
_Gear 1 (small)
_Gear 2 (big)
_1mm Washer
_Filament Guide (1.75 or 3mm)
_Base ( ie "2-3mm Base" for the standard Titan holder, "45deg" for a Delta printer etc)

_Same goes for a Mirrored extruder, except you will obviously need the parts with "Mirror" in the title.
_On my Kossel I'm using the two 2020 45deg mounts on X and Y towers. In the files, you will also find a universal base and one straight mount
_Parts with "Logo" in the title have the Making'Bug logo on them

Printing:

_Supports are needed only for the Idler Lever
_I've printed everything with a 0.4mm nozzle, in PLA (including gears which had lasted for hundreds of hours and counting).
_Print the small gear at 0.4mm extrusion width and 3 perimeters (see the pictures for how it should look in your slicer).
_Print gears and filament guide at 80% infill, 150u layer height and everything else at 250u, 50% infill.
_To check your sizing, test print 5mm of the "Body" first. It should be 42x42mm if you don't measure the corner where the bearing goes. There are 0.1mm tolerances on each side where a part touches the other. That means a 12.2mm hole for a 12mm E3D V6 and the V6 fits well with a bit of pressure. Step files are included if you need to change sizes to suit your printer.

Assembly:

Pictures should make the assembly pretty clear.
1- The small gear goes on the motor shaft teeth side first. It is tight and it needs to be forced on the motor axle down to about 1mm from the bottom. It has to be solid. If you find it too loose check your printing size.
2- Fit the 623zz bearing on the Idler Lever using the M3x10mm bolt. Then fit the Idler Lever in the Body
3- Fit the spring, M4 nut and M4x10mm button head bolt ( or E3d Thumbscrew) in their place
4- Next the Filament Guide goes in the Body; it has a notch on the tip that has to face up
5- You need to file flat a bit of the M5 bolt thread so that the drive gear grub screw could hold. Then slide it in the Big Gear
6- Then the M5 washer goes on the M5 bolt followed by the first 695zz bearing and after that Mk8 drive gear (grub screw first).
7- Align the grub screw with the flat bit of the M5 bolt and tighten it just so it stays put.
8- Fit the other 695zz bearing to the Cover.
9- Fit the M3 nut in its place in the Body
10- Place the Cover over the Body and do the M3x15mm bolt
11- Slide the assembled M5 bolt and Gear into the body and secure it with the M5 nut
12- Undo the drive gear grub screw a bit, then tighten the M5 nut and then do the grub screw as tight as it goes. Then loosen the M5 nut until you can move the gear easily by hand. I like to make a mark on the M5 bolt and nut to see if it moves
13- Use the three M3x30 bolts to fix the Pitan to the motor with the Base bracket between them
14- Chamfer a bit the inside of the PTFE tube end and push it all the way in the filament guide. It will help when loading the filament.
15- Fit a small piece of PTFE tube in the Idler Lever.
17- Set the idler tension by turning the bolt (or E3D thumbscrew) CCW until the M4 nut ends up in the middle of the Cover window. This is a good place to start but it will depend on different springs. There is no need for a lot of idler tension. See Troubleshooting if your drive gear skips
16- Set up your extrusion steps. See your printer manual or search online on how that is done for your particular printer.

Troubleshooting

Mk8 drive gear skips =
You most likely trying to squeeze too much plastic for that particular speed/temperature/nozzle combo. Use a printing speed calculator to check your flow speed. Remember that a Genuine E3D V6 0.4mm has a flow rate of about 12mm/s and a clone hotend less than 10mm/s. Also, expect a 45% lower pushing force and hence printing speed from a generic Mk8 compared with an E3D Hobb-Goblin (source: https://www.instructables.com/id/Extruder-Drive-Gear-Shootout )
Mk8 drive gear wobble =
This has no impact on the printing quality and it's mostly from a cheap M5 bolt but also from generic Mk8 drive gears that can have an ID of up to 5.4mm.
__Noisy retraction =
You can see on the videos how loud should be at 100mm/s retraction.
If your printed parts are well printed and assembled it can only be the bearings.
Most no-name bearings have large tolerances and very little grease.

https://www.facebook.com/MakinBug/

Kudos go to E3D for the Titan https://goo.gl/fcBWLu and to AxMod3DPrint for his Drakon Extruder https://www.thingiverse.com/thing:2172854

https://youtu.be/MrS9Yidgano
https://youtu.be/2xWi5pUNDr8

Enjoy :-)