I have been having issues with my nozzle. It’s clogged up, so I’ve installed a secondary nozzle and put it through its paces. My normal nozzle is a .35 Jhead, my secondary is a .5 JHead. Both are mark V variants. I then printed the same gear, from the same STL, with the same Z steps. Here’s the major differences.
1. Great surface finish difference. .35 has a much nicer finish than .5
2. Noticeable density difference. .5 is far denser, and feels far stronger.
3. In small parts, .35 is faster to finish than .5. Dunno why, but by very small margins.
4. Large parts finish much sooner in .5. A 4 hour print at .35 is 2.8 hours in .5.
5. Predicted reliability. I’ve gotten over a years worth of prints with .35. I’ve also talked to people who can’t get .35 working at all. .35 is a lot higher pressure, and needs a pretty tough Extruder to do reliably. .5, conversely, can basically be hand fed. There’s more room for error in .5, as residue gets left behind. I predict .5 is more reliable.
So, TL;DR — .5 is stronger, faster, and more reliable; .35 is weaker, slower, less reliable, and with a much better surface finish. The pictures don’t do it justice. Surface finish is far superior in .35.