Understanding the parts manual: Nuts & Bolts

[Dan Macdonald]

Gents,
Can you explain to me the nomenclature of the bolts and washers in the parts manual. I understand "M8", but where is the length, thread size/type and plating?
I would like to buy some at the hardware store, or elsewhere.
Do our regular parts suppliers sell normal nuts and bolts?
See below for an example.

[Martin Bruechle]

You might be better off making a list and hitting a VW shop up for some old German hardware vs Chinese at the hardware store.
Many old established shops have buckets of hardware.

Pretty sure 8mm is the thread and 12mm is the length.

[Mike Wilson]

Martin is correct. M8 is the diameter; 12 is the length.

Mike

[Jeffrey Leeds]

There are a number of excellent suppliers of metric nuts, bolts, washers, and whatever. One good choice is BelMetric. https://www.belmetric.com/ They specialize in same day shipping orders.

[Dan Macdonald]

Thanks you all for your replies.

Now how can I tell if they are COARSE or FINE. threads?

[Richard Shilling]

I got this from a hardware supplier on the web: M8 x 1.25 x 150 MM (PT) Coarse Thread DIN 931 Class 8.8 Hex Cap Screw (Bolt) Medium Carbon Steel Black Oxide.
M8 is the diameter in millimeters
1.25 is the thread to thread distance in millimeters. 1.0 is also common and is finer than 1.25.
150 mm is the length of the bolt.
DIN is the older technical standard: Deutsche Industry Normung. Now replaced by CE European Community standards.

[Paul Lima]

Most of the hardware in the 356 is coarse thread. M8-->8 mm diameter, coarse thread--> 1.25 mm pitch, and the manual usually shows length in mm. The DIN number shown will reference a spec that includes the coarse v. fine, the bolt strength, head width across the flats (the wrench size...), and for washers, the ID and OD.

[WilliamVaughan]

Several people have posted to this list in the past regarding Porsche 356 nuts and bolts and their specified surface finishes. I am pretty sure Brad Ripley did at least one post where he related the nomenclature in the service manual to the surface finish type. For example (not necessarilly an acurate example) cadmium or zinc or phosphate. Search the list and you may find more than you wanted to know. Try "fasteners" and "cad" or "yellow" or "accross the flats" or "thread" or "verbus" (or other manufacturers names) or "pitch" (spelled correctly of course). You will start seeing the various message threads.

[JohnPierce]

The bolts, nuts, and washers each have a DIN characteristic. If you Google that DIN you will find what it means. As Richard stated, DIN is an older standard, but still applicable.

[Tom Scott]

This information may help you to understand German hardware:
Definitions

DIN – Deutsches Institut fur Normung (German Institute For Standardization)

How To Describe Metric Hardware

DIN – A Unique Number For The Type Hardware (Hex Bolt, Nut, Washer)

Dimensions – Diameter, Length, Size

Property Class – Tensile Strength

Type Material – Steel, Copper, Brass

Plating – Type Plating Used

Manufacturers Id – NSF, KARRO, F*H, KAMAX, VERBUS

Plating Abbreviations Found In 356 Parts Manuals

Ver – plated

Verzinkt – plated using zinc could be black or silver

Verzchromt Or Verchr. – plated using chrome

Ver Phr E Or Phr B – plated using phosphate, aka Black Oxide

Ver Cad or Cadminum – plated using clear (silver) Cad

Ver Gal Zn – plated using galvanized zinc

Hardware Material Abbreviations

St – Steel

Alu – Aluminum

Cu - Copper

Example – M 6X12 DIN 933-8G phr E - A hex head bolt, 6mm diameter, 12mm long, tensile strength 8G, phosphate plating.


DIN numbers and description

84 Machine Screw, Cheese Head Slotted
85 Machine Screw, Fillister or Pan Head Slotted
86 Machine Screw, Oval Head Slotted
94 Cotter Pin
124 Rivet, Round Head
125 Flat Washer, Standard Size
127 Washer, Lock
137 Washer, Spring
603 Bolt, Carriage, Oval Head
660 Rivet, Round Head
912 Machine Screw, Allen Head
931 Bolt, Partial Thread
933 Bolt, Full Thread
934 Nut, Hex
935 Nut, Hex, Castle Head
936 Flat Washer, Medium Size
960 Bolt, Partial Thread
961 Bolt, Full Thread
963 Machine Screw, Flat Head Slotted
964 Machine Screw, Oval Head Slotted
965 Machine Screw, Flat Head Phillips
966 Machine Screw, Oval Head Phillips
6798 Washer, Lock, Serrated
6799 E Clip
6912 Machine Screw, Allen Head, Low Profile
7971 Sheet Metal Screw, Pan Head Slotted
7972 Sheet Metal Screw, Flat Head Slotted
7973 Sheet Metal Screw, Oval Head Slotted
7976 Sheet Metal Screw, Hex Head
7981 Sheet Metal Screw, Pan Head Phillips
7982 Sheet Metal Screw, Flat Head Phillips
7983 Sheet Metal Screw, Oval Head Phillips
7984 Machine Screw, Allen Head, Low Head
7985 Machine Screw, Pan Head Phillips
7989 Flat Washer, Fender
9021 Flat Washer, Fender
16159 Grommet, Rubber

Good luck, it isn't as difficult as it may seem.
Tom Scott

[Tom Scott]

Here is a more detailed "Sermon On The Nuts" which will provide additional food for thought.

Metric Hardware
For Porsche Models 356 and 911
Tom Scott
This document is intended to provide a basic understanding of the hardware which was used by Porsche when assembling the 356 and 911.
What is the purpose of the DIN number? It is a standardized numbering system which is intended to identify a particular item or thing, such as bolts, bolts, nuts screws and related hardware. There are virtually thousands of DIN numbers today, but this paper will be primarily concerned with those common to early Porsches.
In Europe, the most widely recognized organization responsible for establishing and publishing automotive standards is called Deutsches Institutfür Normung e.V. or abbreviated ‘DIN’. In this country, the Society of Automotive Engineers (SAE) is responsible for maintaining order by establishing many of the standards that apply to American automobile manufacturing.

It should be noted that the DIN numbered parts listed in the parts manuals are usually identified as a ‘900’-part number such as:
900-XXX-YYY-00 where the XXX can be decoded as the DIN number. There is a chart for these codes which I will attempt to re-create or acquire this. Furthermore, the first of the last two digits, 0 thru 7, describes the material used in the manufacturing, and the last digit describes the plating protection. These are: 0 – no corrosion protection; 1 – phosphate, Bostik and Endurion protection; 2 – galvanized coating; 3- varnish protection, and 4 – inkrom protection.
The third set of three numbers. YYY, is a unique identifier for the indivudual part.

The most common DIN Numbers – Nuts, Washers, Bolts, Screws and related hardware are:
84 Machine Screw, Cheese Head Slotted
85 Machine Screw, Fillister or Pan Head Slotted
86 Machine Screw, Oval Head Slotted
94 Cotter Pin
124 Rivet, Round Head
125 Flat Washer, Standard Size
127 Washer, Lock
137 Washer, Spring
603 Bolt, Carriage, Oval Head
660 Rivet, Round Head
912 Machine Screw, Allen Head
931 HEX Head Bolt, Partial Thread
933 Hex Head Bolt, Full Thread
934 Nut, Hex Head
935 Nut, Hex, Castle Head
936 Flat Washer, Medium Size
960 Hex Head Bolt, Partial Fine Thread
961 Hex Head Bolt, Full Fine Thread
963 Machine Screw, Flat Head Slotted
964 Machine Screw, Oval Head Slotted
965 Machine Screw, Flat Head Phillips
966 Machine Screw, Oval Head Phillips
6798 Washer, Lock, Serrated
6799 E Clip
6912 Machine Screw, Allen Head, Low Profile
7971 Sheet Metal Screw, Pan Head Slotted
7972 Sheet Metal Screw, Flat Head Slotted
7973 Sheet Metal Screw, Oval Head Slotted
7976 Sheet Metal Screw, Hex Head
7981 Sheet Metal Screw, Pan Head Phillips
7982 Sheet Metal Screw, Flat Head Phillips
7983 Sheet Metal Screw, Oval Head Phillips
7984 Machine Screw, Allen Head, Low Head
7985 Machine Screw, Pan Head Phillips
7989 Flat Washer, Fender
9021 Flat Washer, Fender
16159 Grommet, Rubber

There may be a suffix, either A or B attached at the end of the Din number and this
differentiates the slight variations of the part, i.e. Din 125 A, flat washer without chamfer and 125 B, flat washer with chamfer. Each hardware item is further defined by: size, both diameter and length; by type of material used to make the item; a code to identify the company which manufactured the item: the tensile strength, and the type plating applied.
The Size described in the Parts Manual will be: M**X**, such as M 8 X 25, the first ** defines the diameter of the shaft, 8 millimeters (mm) of a bolt or screw and the second ** defines the length, measured from the base of the head, as 25 mm in length. Some items do not have a length, such as washers and are described by the diameter only, M 8. Therefore, a hex head bolt, would be shown in the parts manual as: M 8 X 25 DIN 931.
A further complication with size was introduced when the hardware industry decided that the dimension across the head of bolts and nuts, or ‘across the flat’ (ATF), should be changed from 14 mm to 13 mm for 8 mm bolts and nuts. This transition was phased in beginning with the 356 B T6 model. The 14 mm ATF bolts and nut were used exclusively from 1950 until about 1960. However, 12 mm ATF 8 mm nuts were used in some tight areas such as for the carburetor intake manifold where the manifold is attached to the engine head and also where the carburetor attaches to the manifold. This variation may, or may not, be easily identified in the parts manual.
Next the code, or identification for each manufacturer of bolts only, is embossed on the head, such as NSF, KARRO, KMAX, VERBUS, etc. and the property class,( tensile strength) will also be embossed, usually 8.G (for early bolts and 8.8 later years) or 10.9.
Thread pitch for bolts and nuts are standard and not usually shown when referencing these. The standard thread pitch for various sizes is shown below:
Size Standard Fine Bolt Head Size
Pitch Pitch (Wrench Size)
M2 .4 4 mm
M3 .5 5.5 mm
M4 .7 7 mm
M5 .8 8 mm
M6 1.0 10 mm
M7 1.0 10 mm
M8 1,25 1.0 14 mm (1950-1960) , 13mm there after
M10 1.5 1.25 17 mm
M12 1.75 1.5 19 mm
M14 2.0 1.5 22mm
M16 2.0 1.5 24 mm

Type Material
The type material used may be shown in the parts book, such as:
St – Steel (usually a default and not shown)
Alu – Aluminum
Cu – Copper

Plating
Plating – various types of plating was used to protect the hardware item and to prevent corrosion. The processes for various plating methods is a very complex matter, however for our purposes these have been, hopefully, reduced to more simple terms.
The final, and most misunderstood, consideration is the types of plating used on each hardware item is usually shown in the parts manuals and may include the following.
(The following information was derived from a search on the 356 Talk discussions and other resources on the Internet.)
Zinc Plating
Verz. verzinkt, or verzenken in German, was one of the most common and inexpensive methods to protect steel, commonly described as ‘zinc’, or ‘St-verz’ in the parts manual. This process was a single stage and was not finished with a chromate wash, or conversion. This offered the least amount of corrosion protection and is often called ‘black oxide’. There was a second type of zinc plating, referred to as ‘gal Zn 9’ in the parts manual, or “black zinc” which was the standard zinc plating followed by a chromate conversion step which added additional plating and protection to the item.
Gal Zn 12 was a zinc plating process which produced a silver finish.
It is my opinion that, as a general rule, most 356 bolts and nuts were plated using a combination of black oxide or black zinc from Pre A up to the introduction of the T6 B model at which time silver zinc was used through the early 911 model, about 1965, when yellow zinc chromate was phased in. This was a plating method similar to black zinc but a yellow chromate conversion was applied following the initial step.
Phosphate
‘Phr E’ and ‘bost’ refer to Phosphate and Bostik-Endurion, an anti corrosive finish baked over phosphate – Bostik the manufacturer and Endurion the process. This type plating is identified as ‘phr E’ and was commonly used for all types of washers and some hex nuts. This process also produces a black finish, similar to black zinc. I cannot explain why the two types of plating, zinc and phosphate, were used, perhaps it was the manufacturer’s decision.
Cad or cadmium offered a better anti-seize and lubricating properties for nuts, bolts, screws, fuel lines and carburetor linkages. Cadmium is an electroplating process where cadmium is applied and then a supplementary coating is applied to produce a grayish silver color, commonly referred to as cad type 1, or Cad type 2 which has a yellow or gold finish.
Type I, ‘or referred to as clear cad’, results in a silver appearance and was used primarily for engine hardware for 356s from 1950 to 1965. The parts which were cad plated are usually identified in the description in the parts manual. The use of ‘clear cad’ on engine components varied by year and type of hardware and what each of these was is a topic for later discussion.
Type II yellow zinc chromate - results in a gold color was referred to as ‘Gelb Chromatiert’ in the 911 parts manuals.
Chrome
Verchr is used for many special parts such as head light rims, top latches, outside door handles, switch bezels, inside door handles, etc.
Nickel
Only a very limited number of parts were bright nickel plated. These were: Hazet wrenches, seat rails and screws for Pre A, A and B T5 models, Speedster seat hinge hardware, tool bag and tonneau cover buckles, keys and hood and engine release cable clamps
Anodize
Only a limited number of parts were anodized, another plating process. For the A model, the hood handle and some bumper guards, and the bumper and rocker trim for B and C models were anodized, This process is similar to chrome plating but produces a less shine to the finish.

What Is The Bottom Line To The Type Plating To be Used In A Restoration?
It seems impossible and unrealistic to attempt to re-plate hardware using the plating types specified for black plating in the parts manual. It is possible to plate hardware using black oxide or black zinc, however black oxide is not very durable and is prone to rust and corrosion unless the hardware is treated regularly, and often, with penetrating oil. Black zinc is much more durable and long lasting and is very similar in appearance. Attempting to re-plate the hardware using phosphate is likewise difficult and unreasonable. So, depending on your level of fanaticism, it might be acceptable to plate all parts identified as: zinc, gal zn9, bost., and phr E in the Pre A and A parts manuals using black zinc and achieve a reasonable, durable, maintenance free and acceptable appearance.
What do you think?
Dr. Half Nuts

[Vincent Gillespie]

WOW!

[Mark Sabbann]

DIN – Deutsches Institut fur Normung (German Institute For Numbering)

Normung is 'Standardization', not 'numbering' - German Institute for Standardization

[Dan Macdonald]

Tom,
That info is INCREDIBLE!!
Thanks so much!

[Ron LaDow]

Hey, Moderator!
Suggest at least Tom's posts as a stickee.