SD4 Dual Extruder Mod Sponsored! Ready to begin. Need community Input.

Consider using a geared setup with those motors in a bowden setup to get more torque.  There are several geared greg wade extruder variations on thingiverse.  I also like the herringbone or fishbone gears.  You will need to get a very high quality gear print to avoid excess noise.  If you find a geared setup that you like and it is a direct drive setup, E3D makes an adapter that you can use to convert it to bowden.

I have one printer with a bowden extuder and a geared NEMA 17 extruder motor.  I have not tried it with a direct drive setup,  so I'm basing this advice on what I have heard from others but it seems to make sense.

Can you link to The .Stl files and threads for those? The thing I'm most concerned with is mounting the extruders to the Solidoodle Carriage once I take the motor off. I think either finding or creating a piece to do that as fluidly as possible is what will make this build really easy for allot of people.

Also please let me know what you think of what I have chosen so far and if there is something you think I should change.

I currently have a .25 nozzle on my E3D V6 and that is giving me some amazing detail.

Yeah I wrote that last post in a hurry. I wouldn't dare try this if I wasn't sure I could do it...(Not that I want to jinx myself!)

Thank you for those......I still have to decide on whether or not to actually print the gears or not. I'm going to  print a couple in a bit while I'm running this .25 nozzle. I'm planning the extruder location now and I'm trying to decide where I want to put them. People with the open frame models mount them (from what Ive seen) hangin over the top rails, but of course they kinda have to. I was toying around with idea of putting them below the spools and printing a spacer to go in between the spools since 90% of the spools are the thinner type that allow you space for 3 on the back of a solidoodle 4.

You do bring up a good point about the mounting of the hot ends.  Personally Ive always turned down the mounting rings and used the original mount but I don't want to do that with this build. I did notice when I changed the nozzle that what stops the barrel from threading in is when it hits the nozzle so Ill have to wait until I have them to tell whether or not I will need to make the height adjustable to account for that. Technically only one would have to be adjustable so that it meet the fixed one if that is indeed a problem.

In the future I could see a really precise stepper motor on one that could almost double the printing speed by laying down one layer right after another......Albeit with some creative engineering and software algorithms. Would work great for some objects but not others.

I don't think Ill go as far as this but I think what your talking about could be achieved fairly easily if you used a couple gears to get a ratio that would allow you to make those kind of adjustments.

As for this one It should be easy to get them aligned by loosening the one that can move and raising your z axis up to the nozzles and then tightening it down. (assuming your bed's level)

Although I'm sure this would involve some pretty major adjustments to the RAMPS 1.4 firmware. (Although someone may have already tackled that I'm sure)

As far as where I am at in the build I have a couple of decisions to make....3 Actually.

1.  being whether to keep the board inside the print chamber like it is now where everything is already ran to OR on the back of the printer. IT will still be in roughly the same location so a couple holes and gromments and the wires should reach without any problem. The new power supply will go on the back or side depending on a few other things.

2. Is the location of the Extruder motors AND whether or not to keep the lid on the printer or to take it off. Taking it off would allow me to put the extruders on an overhang mount like I have seen people do with there Solidoodle 2 and 3's. Ive completely nixed the idea of mounting the extruder motors on the carriage because the S4 is already finicky enough with just 1 stepper motor. So I have to decide whether to mount the extruder motors Below the Spools or to take the top off the printer and hang them over the side.

3. Mounting the Hot Ends on the carriage. This is probably my foremost question. I can easily print a piece to sit on top of the existing y axis carriage once the motor has been removed. But I also think printing a single piece carriage with the mounts already on it would be a good idea. Currently Im looking into the carriages made for the S3 dual extruders and as long as the spacing is the same using one of those.

If anyone has any ideas or has done a similar mod themselves please let me know what you think.

Yes thats what I was talking about by remote mount extruder motors. The cariage is way to finicky to have the weight of a second motor so it pretty much has to be bowden.  But Normally on the SD4 you mount the hot end to the parts that are attached to the extruder motor, but once I remove the extruder motor I have to decide whether to  design a kind of bracket to mount the hot ends to or just design a whole new carriage. I'm really interested in how people have done this in the past with SD2 and SD3 printers.

The other thing is where to remote mount them. I was going to mount them above or below the the filament spool, but I am considering the the "Over the side mount"  without the lid so there is more room to work with.

I'm currently doing the research on this but I thought I would update the thread and see if anyone had some input that might help.