https://grabcad.com/library/erebor-dwarf-helmet-1

Originally inspired by the helmets worn by the dwarven warriors of Erebor, I liked the shape of this so I tried my best to make it printable (with permission from the original uploader). I will admit the version shown in pic is the only one I've made, but will upload new pics when I have made the other version. I used this for DND cosplay as my dwarf cleric of Onatar, Runebrand. I hope to revisit this so I can add the ornate details and filigree I feel it deserves.

#General notes
All parts sized to print on a 300x300x400 print bed (but if your head is large you may have issues?). I printed all components with 3 walls, 2-3 bottom layers, 4 top layers, .2mm layer hieght.

I find it's the right balance of speed and strength, but also generally prevents infill patterns from being visible on the skin of a print.

Sizing

I will update in a short bit with the inner dimensions, and you can do your own math to scale the helmet to a size that fits your head. I personally double checked the size of my head using two soda cans on a table top, putting my head between the cans so that they touched the sides of my head, and then measuring the distance between the cans. I repeated this step for both length and width. Using those measurements I then made a mock up of the helmet using cardboard to be reasonably sure the fit would be fine. It's crude, and maybe there's a better way, but hey, it worked for me sizing this correctly. Note: Plastic helmet on scalp is typically uncomfortable. I would add some extra height to the helmet top to accommodate foam padding. Make sure to scale the shroud to the right X and Y percentages for your helmet top.

#Printing notes
###Helmet top
The helmet top is universal to the shrouds.
For my print I used matte black PLA with 11% gyroid infill, and this was more than strong enough. It will need supports to hold up the middle of the dome if printed in the orientation I have placed it in the file.

###New style shroud
I may recommend it be printed with brim to keep it firmly on the buildplate, as I had adhesion problems due to it's small contact surface. Because it is so thin I left the infill hollow (0% infill). Solid infill may work as well, though I think it may benefit from the flexibility of keeping it hollow. Supports are needed.

I have made a version of the new shroud that is split into two halves, this should be able to print on a the smaller 220x220 build plate. Join the two halves using the same peg used to join the shroud to the helmet top. this will also require some glue.

###Classic shroud
This is closer to the armor of the Erebor dwarves though there is a lot of detail left out. Supports enabled and the equivalent of cura's "Supports placement: everywhere" are needed here. There is more density to this component, would use infill, and at a higher percentage than the helmet. I used 20% gyroid infill.

###Nose
Nose doesn't really require any special printing instructions. Nose v2 simply sticks out less than the original.

###Pegs
Pegs should all use 100% infill.

#Assembly
Simply use the correct pegs in the right holes with glue to attach the shroud to the helmet top. Glue on each of the pegs, and I used hot glue all along the inner seam of the joint between the top and the shroud.

special thanks to the "Head to scale with my head" guy, was useful for sanity checking dimensions. https://www.thingiverse.com/thing:4918804

The Beard

Due to popular demand I've linked to the beard and wig I'm wearing in my pictures:
https://www.amazon.com/dp/B076MGLWFV?psc=1&ref=ppx_yo2ov_dt_b_product_details
If this link ever goes down, I would recommend searching for "viking beard".

Truth be told I find it hard to recommend this product because the mustache, which was supposed to be adhesive and separate from the beard, turned out to be some eldritch horror of anti-adhesion and was impossible to attach to my face, other than by copious amounts of spirit gum. In the attached pic I've just temporarily tucked the braided ends of the mustache beneath the beard, and others in the reviews mention sewing the mustache to the beard to hold it up. That is probably the best course of action, but there are probably simply better products out there that don't require such faff.