3mm vs 1.75mm

Hi guys,

I am currently building a Prusa I3, everything has been going fairly well so far.

I was assembling the extruder, made a hobbed bolt and put it all together. As the hobbed bolt was fairly rough, I thought I would go out and buy some filament and feed it through to make sure that it gripped well and works ok. So I went and bought a roll of 3mm filament, when I came back I realized that it didn't fit through the hole in the extruder body, or the hole in the hotend.

The extruder body obviously isn't a problem because I could always drill that out to 3mm.

I had it in my head that I had purchased all the components for a 3mm extruder when I bought them quite a while ago, but I'm guessing as the hole for the filament on the hotend is smaller than 3mm, that I have a 1.75mm hotend?

So my question is this. Am I better off sticking with what I have and getting some 1.75mm filament and using that instead, or should I get a new replacement hotend for 3mm?

I have done a bit of research online on the advantages and disadvantages of both but I haven't really found anything definitive.



Photo of what I'm talking about is attached.

Thanks in advance!

This is a personal choice

Though in some places. like here, they try and sell by the meter so 1.75 is expensive...

Main difference is you can direct drive 1.75 without any gearing, with 3 you really need a geared extruder

Print quality is the same.

At this time, even though i'm a very strong 3mm supporter, 1.75 seems to be the way everyone is going.

I use both, and have a firm preference for 1.75. 3mm is much harder on the extruders and also a major pain for general handling - it's much more likely to throw a loop off the spool, and 3mm pla is more likely to snap while you're trying to feed it into the extruder (or if you look at it funny). The only time I prefer 3mm is for flex filaments where the 3mm is less likely to buckle in the extruder than 1.75. If it wasn't for that, I'd probably dump the 3mm capability and move entirely to 1.75.

I strong disagree regarding throwing a loop, at least in regards to PLA.

I find 1.75 is constantly trying to unspool in weird and random ways, where as 3 just stays put.

Edited 1 time(s). Last edit at 05/02/2016 05:24PM by Dust.

That's interesting, must be a difference in the layout of the filament feed. My setup is a bit cramped with the spools mounted on top and a relatively short path to the extruders, especially when it's at the top of the Z travel.

Thanks for the information guys, very helpful.

I am thinking I may stick with the hotend that I have then, and buy some 1.75mm filament and use that instead of the 3mm I already have.
Once I have it up and running, I may look at making a separate setup to run the 3mm filament and see how it goes.