Terminology Question - Lock Washers and Bolts

[Highfield]

I have read the Haynes Manual and reviewed the PET Diagrams, along with other literature, and get 'confused' over some terminology, which is imprtant if I am to get the correct fasteners etc. when re-assembling my various components.

Can someone clarify and maybe post a picture of a Lock Washer.

I have some flat washers with minor angled serrations (spelling ?) on both sides, as well as what I refer to as spring washers (split and bent up at the join to then compress when tightened). I have also been given washers that were described as Lock Washers that have ridges sticking up all the way around both sides.

When purchasing nuts and bolts, are those used on the 911 a standard pitch, and if so, what is it ?

Lastly, I note that most of my bolts are stamped 8.8, but am I correct in thinking that some should now be 10.9 ?

Do they have to be purchased from Porsche ?

Thanks,

Ian

[HarryD]

Tricky topic. Our pals at McMaster Carr have a Web Page (http://www.mcmaster.com/#washers/=2pvn11) showing most of the type available.

The ones we see most commonly on the car are: Flat; Spring lock; Wave; Belleville; and Wedgelock.

As far as the standards for Hardened bolts, As you noted, many are 8.8 (which is about the same as an SAE 5). The 10.9 correspond to a SAE grade 8.

Like SAE, they typically come in a normal and a fine thread. Ususally, the normal thread is what is used. Again, our pals at McMaster Carr can show you the range of choices.

As far a buying the hardware, hardware is hardware. Unless it is a special part made for Porsche (odd shoulder or other feature), any QUALITY supplier should be ok. Some opdd ones that leap to mind are the seat belt bolts and the screws that hold the window cranks. I am sure there are others.

[Flieger]

The serrated washers like for the CV joints are also called Schnorr (I think that is how it is spelled).

[HarryD]

This web site is quite informative as well: http://www.jamesglen.com.au/training/training.htm

[jcge]

Look for a DIN standard reference for your German fasteners...you can't go wrong if you have that info for the fastener, washer etc that you're after

There's a good overview at Fuller Metric

[Highfield]

When PET refers to M12 X 35, then that is obvious.

However, they sometimes throw in a third dimension - M12 X 35 1.5 (?) - does this refer to the pitch, and if no pitch is referred to, then is it standard (course) ?

I like Porsche as they are yellow coated, whereas others generally seem to be 'silver'.

Ian

[jcge]

The third dimension in this instance is pitch - 1.5mm

Usually (but not always) if there is no pitch stated then you'd assume coarse series. Luckily, you usually have at least one piece of the puzzle at your disposal - a nut, fastener or threaded component that you could measure, or test fit.

You may find it useful to collect a few different sizes and pitches of bolt and nut to allow you to do a fit test to confirm the unknown.

[jcge]

For non critical applications, in the larger diameters (M12, M14 ++), many manufacturers tend to favour the finer pitches

Conversely in the smaller diameters (-- M6, M8, M10) , they usually favour the coarse pitches.

[304065]

The specs are like this

M10 x 1.5 x 50 DIN 933 8.8 Phr

That is

10mm metric thread diameter
1.5 mm thread pitch
50mm grip length- from end of fastener to under screw head
DIN 933-- DIN standard that describes fully threaded/ partial threaded and other properties
8.8 = property-class (Describes tensile strength)
Phr= phosphatierien = "phosphate coated"

also don't forget the headmark, which is the manufacturer, like "KAMAX"

[Wil Ferch]

The serrated lock washers that are "Schnorr" have the "peaks" angled to provide resistance to unwinding...the peaks are not symmetrical. Schnorr come in "S" and "VS" strength grades...corresponding to 8.8. and 10.9+ strength grade I believe...as they are like belleville washers in concept..and squish flat against an internal spring constant when torqued down under a screw head.

see here--> http://www.schnorr.com/safetywashers.html

[Cooper911SC]

Others have clarified the DIN and size standards.

You want WURTH Metric Gold Cadmium or Yellow Zinc plated hardware assortments. Try searching our host's site or give them a call and see if they can order it for you.

I stock WURTH products for my business but am not a re-seller. Good stuff to have around.

You will spend some $$$ but it is nice to just walk over to the drawer and pull out nice new hardware!

[Highfield]

Thank you for all the posts, and the clarity I know have.

Yes, it would be nice to have an assortment of the more common sizes so that I can just 'reach over and grab one'.

It will make reading PET and other sources easier.

One final question - when a diagram refers to just a 'lock washer', does that by default mean a particular type ?

Ian

[Cooper911SC]

Most of the time when Porsche calls out a lock washer it is a split type lock washer.

I know in some areas like for example the inner door of a 914 there are star type lock washers.

Another piece of fastener/washer useage to remember is the order in which things go... for example, part, flat washer, split lock washer, bolt.

Anoter way to say it is that you almost always want to have a flat washer against what ever part you are bolting on. This protects the part from getting scored by the lock washer and also distributes the load more evenly.

My .02

Cooper

[Highfield]

Thanks Cooper - by split washer, do you refer to what I call a spring washer ?

i.e. a cut in the washer that then lifts one edge that I presume 'cuts in' to the flat washer.

Ian

[Cooper911SC]

Ian, Yep that's correct. Spring or Split lock washer.

Coop