The idea is to click on a link.

I am looking at M1897 type Helmets. The development of Pickelhaube over time is in another section. The identification guide below is just a broad generalization.  One thing that makes this hobby so much fun is that it has so many nuances. The following example is a  sample only. There are MANY variations on a theme.  I'm just building a generalization out of popular demand. 

Infantry Man

Cockade 

There are many color charts of landes cockades.  This is just one. I have an entire article on the so called "NCO  Cockade" at http://www.pickelhauben.net/articles/NCOCockade.htm. I plan another full article on the landes cockades. There were two styles of cockades. Serrated and Non-serrated.  In addition there were little holes and big holes.  Small holes were for use with with chinscales on screw post rosettes. "Big Holes" handled M91 posts. 

Serrated (pointy things all around)

Non serrated

Little Hole for use with with chin scales on screw post rosettes

Big Hole for Knopf 91

Sometimes an OR cockade for a Knopf 91 

had a "slot" cut in it like the one below:

Chin Scales or Chin Strap

Two basic styles convex and flat.  Sometimes it is REAL hard to tell. Chin scales were made by alternating 2 and 3 finger links with a leather strap on the inside.  the chin scales fastened in the front and there was a buckle on the leather. Chin scales were capped by the rosettes. Width of scales 13mm in front and 23mm in back for flat scales.  Width of scales 14mm in front and 26mm in back for convex scales. If no rosette you have an OR set of chin scales to fit the M91 post like the one below. Each half of the chin scale was  were 16.8 CM long. M91 posts used a leather chin strap with a metal fastener instead of chin scales in 1891 and beyond.  Mounted troops did not even adopt the M91 until 1894. Chinscales were used by mounted troops and Guard units. Straps were only used during field maneuvers. 

The cockades changed to accommodate the larger M91 posts. However, a Canadian collector made an absolutely brilliant discovery that the thickness of the hooks and posts also varied. He showed conclusively that chin scales were 3mm thick as were mounted "field use" straps. Posts were longer to fit these, Infantry strap hooks were only 1.5 mm thick. Thus you can pay close attention when cockades "wobble" when they shouldn't ... perhaps they have the wrong thickness of hook. This discovery was shared at the forum at www.pickelhaubes.com   Always good to learn from other collectors.

Kügel 

All balls are not equal.  Similar to spikes they ranged greatly in size. The official regulation size was 4.5CM but like spikes no one listened to the regulation.  The biggest difference in balls, spikes, and trichters is thread match. There are at least three different thread sizes. Tops and bottoms had to match and the DOV catalog warned buyers that spike base had to be provided if they didn't make the helmet if you wanted a ball or trichter.

Pearl Ring

There are two kinds of pearl rings.  Old style which were discontinued officially for many units in the 1895 pattern OR helmet. OR pickelhauben are often called "NCO pearl rings" in error. Every OR had them up until 1887 and some unit types retained the old style pearl ring right to the end. It is possibly an NCO but more probably an OR. If you have a 48mm cockade with a silver ring it could well be a Feldwebel.  The Officer or private purchase pearl ring was the egg and dart variety. 

Rear Spine

Supposedly 430mm long and 14 mm wide. Most had vent sliders as pictured but artillery ones in 1903 and some later did not. 

The 1903 Bekleidungsordnung is clear about no ventilation but I do not know when or if it changed. 

Next 4 pictures with permission from the Bellars collection.

Shell or Corpus 

The helmets were, by regulation, supposed to be 1050 mm-1250mm high.

Most issue shells were marked. This was not uniform but often contain maker marks and depot marks.

Spike

OR Spikes were shorter and squatter than their officer counterparts. All Spikes are not equal.  They ranged greatly in size. The official regulation size was 6 cm. If the regiment wore a parade plume the top of the spike would unscrew. If no parade plume most enlisted issue spikes would not unscrew.  The biggest difference in balls, spikes, and trichters is thread match. There are at least three different thread sizes. Tops and bottoms had to match.  Notice there are no two rings at the base of the spike. This is an officer standard for round spikes.  Lack of these rings means not commissioned. There were also different types of fluted spikes.  

Spike Base

There are multiple types of these.  The two basic styles are round plates and cruciform bases. Round bases are simple.  Round with four domed studs attaching the helmet to the shell. Cruciform bases have two different styles based around the front leg.  Hessian cruciform bases have equal length legs. Bavarian Cruciform bases have a shorter front leg.  Long legs 70mm short leg 40 mm. 

Round

Cruciform

Dome Studs 

Those not commissioned normally had "dome studs" in place of the star studs. Fähnrich often used dome studs as a way of marking their helmets as "not quite officer yet.)

Vent Holes

The Model 1895 helmet increased the number of vent holes in the spike base from 2 to 5. 

Visor 

The brass colored trim is supposed to be between 380-400 mm wide and 8mm thick for issued OR helmets (top photo). This is significantly thicker than private purchase trims (bottom photo).

Visor Studs

These were stuck through holes on the visor trim through thru visor.

Wappen (Helmet Plate)

Lots of wappen obviously.  Below is a short diagram of different types.  In General Officer Wappen are "pierced" That means the crown on the eagle is voided and has holes in it. There are exceptions like Mecklenburg-Strelitz but it is a rule of thumb.  A Voided crown does not mean commissioned officer. It means privately purchased higher quality plate.