How to identify nozzle size?

I think my printer may have come with a larger nozzle than the standard .4mm nozzle - when trying to calibrate flow it seems like I’d have to drop it to like 73% which seems out of whack. But I don’t want to take the nozzle out if I can avoid it. Is there a test I can do to identify the nozzle size so I can set it up in my slicer properly?

I had that same issue trying to calibrate value pla. I gave up since it still didnt print well and i went back to 100% flow.

Your nozzle could be worn or damaged if its heavily used or smashed into the bed too hard/many times. Which means youll have to change it.

You could retract the filament and try a .4mm acupuncture needle and see if it goes in. Or just try 0.5mm/0.6mm nozzle sizes in your slicer though id be surprised if you did get a different sized nozzle in your printer.

With the nozzle clear of obstruction (and hot), push a bit of filament through it. The filament should hang free. Not too much though. if the filament strikes something before it hardens, it will create a bit of back pressure that will cause it to thicken. If it is allowed to grow too long, the weight of the filament will stretch filament still coming out of the nozzle, making it thinner.

Use a decent set of calipers a micrometer to measure the thickness of the extruded filament. If it hasn’t been stretched or squashed it should be very close to your nozzle diameter.

And yes, as Dr. Marvin pointed out, nozzles, particularly brass ones, can wear down surprisingly quickly depending on the type of filament you print with. And by wear “down” I mean that they wear from the inside out making the hole larger and usually less rounded.

Some nozzles have the size etched on them on the hex flat. They can wear very quickly, one 2-3 hour print can eat a brass nozzle (carbon fibre, any ‘fill’, glow in the dark…) The worn nozzle prints badly generally, more stringing, blobs, and so one.

If you have been making a bunch of prints and it has changed, just swap out the nozzle. If you suspect it is off, swap it out. They are a disposable part and a wear item. On occasion you get a bad one where there is a burr or something as well, even new ones can be bad.

I tend to use stainless steel, hardened does weird things with temps, and brass for me don’t last very long I get tired of swapping.

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I’ve done that test. I measured the extruded filament with my verner calipers and it’s 0.85 which is why I came to the conclusion that the nozzle is bigger than 0.4 which i expected.

I’ve only run through the one roll of ABS that came with the printer so I can’t believe it would have work out the nozzle…

Where do you source your nozzles from? If I have to buy some I might as well get a few different sizes…

By the way, I didn’t give the obvious answer to your question: the nozzle size is usually printed on the nozzle. If you take the silicone sock off, it should be printed on one of the six sides. Mind you, I have a few nozzles that don’t have it printed.

3DPC has nozzles. Amazon has nozzles. As I say, and especially if you are getting a variety of sizes, try to only buy nozzles that have the size stamped on them.

Most of my nozzles are brass, but I did buy some hardened steel ones as well in case I ever print anything abrasive. I find the idea of filament being abrasive, given that it’s a liquid and coming out at a very slow speed, to be very counter-intuitive. However I’ve seen enough people talk about it and posting pictures of worn nozzles, that I’m inclined to believe it. I have no first-hand experience with this yet.

One minor point to make that I discovered when I was nozzle shopping: most printers use the same semi-standard nozzle size. And by size, I mean how long the tip is (short and blunt vs. long and pointy), and how long the thread is which affects how far up into the printer it can go. Be sure to stick with a nozzle of the same dimensions as the printer manufacturer’s originals.


I removed the fan shroud and silicone sock to check that nozzle and sure enough it’s a 0.4:

I have no idea why it would be extruding as much as it is but I guess I’ll order some new nozzles. Are there any favorites you have? What do you use various sizes for (aside from, I presume, printing larger pieces faster)?

Would it maybe have something to do with the fact that I’m running a micro swiss direct drive and hot end? Would that somehow push out more? Though you’d think that it’d still be roughly a 0.4" extrusion as opposed to closer to 0.8"…

I figured I’d better test it before replying. My 0.4 nozzle extrudes into air between .38 and .55. I hadn’t realised there would be so much variability. I’m really not sure why. I would have expected it to be more consistent. The .38 is probably where the filament was starting to stretch under it’s own weight and I suppose the .55 could be because I’ve been using this nozzle for a few weeks? I don’t have enough experience to know how fast a nozzle should wear.

Anyway, I don’t have a “favourite” nozzle. You’d have to ask someone with more experience printing a variety of material.

I don’t think the MicroSwiss has anything to do with it.

Also, with respect to nozzle sizes, I’ve experimented with sizes up to 0.8 with fairly good results. Yes, you can print much faster and apparently layer adhesion is better (I haven’t noticed myself) but it does come at a loss of fine detail.

I haven’t printed with anything smaller yet. I’ve read they are prone to jamming if there are any impurities in or on the filament. On the plus side, apparently they are good at printing fine details.

I did the teaching tech flow test for something a little more reliable to measure and my wall size, which was expected to be 0.4mm was between 0.52 and 0.59 mm. Using his calculator at an average of 0.55mm it says my flow rater should be at 73% which seems really weird.

I’m hoping to get things dialed in tight for dimensional accuracy (as much as possible anyway) so this seems like it needs more.

Change the nozzle to a brand new one then re-do the flow test.

Gotta order some new nozzles…

Hello Moose.

I’ve come across this issue Before where Orifice hole was larger than Spec.

I have Several Pin drills for Nozzles. I just Warm Nozzle and push one of these in it to check what
the orifice diameter truly is.

I also keep these Drills (Pin/Finger/Thumb drills) around to re-drill worn out nozzles to the next larger size.

0.4 => 0.6 => 0.8 By this time they’re worn right out oval and not worth drilling to 1.0mm. I have tried going from 0.8 to 1.2 for testing, however you have to print so slow with Creality hotends (Flow melt restrictions cm3) that it’s not worth such a large hole.


I Hold no Ownership of these Pictures, they’re ones I’ve pulled from internet for teaching Customers.


That’s a neat idea! I’ll have to get me some of those pin drills. At the very least I’ll know what the heck size this actually is. Thanks for sharing that!

So in your opinion are the only nozzle sizes to consider .4, .6. and .8?

I Mostly Buy (A360 Brass) 0.4mm Official: E3D, Creality, Ultimaker Nozzles. Then just drill them out as they wear.

Hardened Nozzles, Toss when worn out, the drilling process changed the heat treating on the tips, making them too soft!
For hardened I normally Buy 0.6, 0.8mm

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Thanks Keith! Can you tell me a bit about the different situations where you’d use the various nozzle sizes and types? I’m still new at this but would like to learn when different nozzles would be advantageous.

Brass nozzles for regular PLA and PETG
Stainless for constant PETG, ABS and Nylon (any higher heat filaments)
Hardened for PLA carbon fibre, wood, glow in the dark and any metal filled filament. Same goes for PETG carbon fibre, ABS carbon fibre and Nylon carbon fibre.

With any abrasive filament, I use a .6 nozzle. Seem to clog less than the .4.

If you put on a hardened nozzle, then print a couple of jobs in PETG carbon fibre, then are going to print PLA for the next number of jobs, you do not have to change the nozzle back to brass.


That’s awesome info! Thanks!!! What about when you’re printing larger pieces (helmets, etc)? Do you stick with .4 or is it better to go bigger?