Following a very brief exchange with Dabinielson after discovering his latest design, I decided to try converting my E2 over to direct drive. Well, technically short drive - there's still a few cm of bowden involved - but it's close enough that it doesn't really matter. The short of it is that I'm extremely impressed, and I also feel somewhat enlightened.
Firstly, it works. I had my doubts with the extra weight going onto the cantilever but I'm not seeing any indication of sag across the X axis. Layers are incredibly even, corners are outstanding, and there's basically zero ringing to speak of (though my acceleration is a very modest 600m/s²). Longevity remains an unknown but I'm extremely optimistic.
As for the enlightening part, however, take a look at the attached image. The cube on the left was printed with the exact same settings I used with a bowden. Note in particular the coarseness on the right-hand side of the Z on top. The one on the right has just 2.5% less extrusion, achieved by adjusting my e-steps (I realised I'd never calibrated my BMG). There is still a little bit of roughness (I might drop it another 0.5%, or 3% overall) but that's a significant difference, especially for an issue I'd never noticed with the bowden.
Also worth pointing out is that the seam is in view, on the left-hand side of the X face. It's only barely visible on the over-extruded cube, and you have to get it under the right lighting to even make out the seam on the right. I can honestly say I never even saw anything close to that with the bowden, and those corners are nothing short of amazing.
Unfortunately I can't say that I used Dabinielson's design. I have a BMG clone, which I wanted to keep using, so I've instead opted for a SpeedDrive (the V2 remix, so if I switch to a pancake stepper later I get back my X space). But if you don't have a BMG (or a separate part cooling fan) than it could be worth at least experimenting with. After all, it's a non-destructive and completely reversible modification (provided you have a little bit of spare bowden tube, at least).
I'll touch back on this in a few weeks to let you know how (if) it's still going. Meanwhile I just need to get this extrusion wound in!
SpeedDrive by Sashalex007:
5mm/s square corner speed
0.08 pressure advance
Been an Ender 2 owner, I wanted to know from everyone if you have had success with printing the Makerbot T-Rex?
I've been finding it very difficult to print with a 0.4 nozzle and adjusting my printing to 0.15.
Should this print require a 0.2 nozzle?