My Prusa i3 came with the Mk7 extruder. It works ok, but the roller assy isn’t so great. I’m looking at upgrading to the Mk8. I only print in ABS and PLA at this time. For $40 is it worth it, or should I look at something else?
MK8s don’t actually have a better drive gear than MK7s: AFAIK they use the exact same one. The main advantage that MK8s have over MK7s is the lever idler, which allows for quick adjustment of filament grip strength as well as quick releases of filaments, but you could actually just print a new MK7 block with that better idler. Of course, MK8s are made of aluminum rather than plastic.
If you’re okay with just upgrading your MK7 instead of replacing it with an MK8, MK8 extruder blocks are extraordinarily cheap, and should be directly compatible with all of the other MK7 parts.
IMO the biggest difference you could make in your extruder without going with a geared extruder is swapping out the drive gear for an MK8 drive gear (which confusingly isn’t the same drive gear used in the MK8 extruder). The smaller effective diameter gives you more precision as well as surprisingly better grip. However, that means you’d have to find a compatible extruder design, and that extruder design may not actually be compatible with your existing hotend.
Hope this helped!
-Karl
