I did the conversion last weekend, will post build pics below.
I am currently fighting the BTT Octopus Pro with TMC2240 drivers. The documentation is hard to find, multiple revisions, and they changed pin outs. First board was bricked, couldn’t even get it into DFU to redo the bootloader. Second one suddenly decided to stop connecting. Idfk
I will say that the klipper part of the conversion, from Creality board to a controller board, is far far more daunting than the physical conversion from Cartesian to corexy. Mind numbing my difficult with no sample configs to even base settings off and no prebuilt firmware.
I am going to return the BTT Octopus and use a Fystec Spider 3. Much better documented and by all reports more robust and durable. Not sure I would ever buy another BTT board after this. Also switching to TMC5160t Pro drivers for xy and 2209 for z & e after this.
Just too many undocumented settings for the 2240 drivers that make it a nightmare. Apparently the Klipper team got in a pissing match with BTT over how they went about releasing a product before securing support in the community for it. Much like how the Voron community stopped support for Slice Engineering which has resulted in using community, poorly QA’d designs for the print head.
This has resulted in me designing my own print head specific for my use case with the hardware I have. My goal is to use the Voron Stealth burner and make it stronger, smaller, and have better parts cooling. I want to maximize my print area so an ungainly modular print head is an impediment to that. I have a good idea what to change and how to accomplish my goal, will share my development.
I also had a problem with the Mini Sherpa extruder, where I ordered the 8 tooth and got the 10 tooth. Well, the 10t does NOT work with the 8t settings and it took a few days to try the other gear ratio as I chased down other possible culprits.
Then once I get that all sorted and the rotation distance right, it kept crapping out on the UART connection between Octopus & Pi. Idk if my jury rigged cable is too long, too much interference, or what but I will be using usb on the next setup. UART is fine for drivers but not communication over distance.
Anyway, here are some disassembly pics:
Took it down to the studs. Then reinforced the snot out of it with corner brackets and braces in every corner. The stock blind screws had it out of square so I replaced many of those with mlok t nuts that depend less on the angle of the threaded hole.
This was 1-2 days of straight work.
Then began assembly, where I discovered that most of my parts were over extruded and needed to be “adjusted” for fit and fasteners. I should have done all this work ahead of time. =\
Corexy system coming together:
And finally electronics, where I discovered that the stock creality 4.2.2 board has a setting called stealthchop that doesn’t work with extenders for some ungodly reason and can’t be turned off. So I had to scrap the stock board and use the Octopus, which has had a massive massive slew of its own issues.
It was at this point that Belt tuning occurs. And where I discovered that if your belts aren’t IDENTICAL LENGTH, your gantry won’t be square no matter what you do. So apart it came and I redid the belts. Three times. Then clamped the gantry to the front towers and finally got it right, using a sound app to tune the frequency of the belts for tension.
That’s where the Octopus saga begins and I won’t bore you with that.
Hopefully my next update will be more positive.