FAQs

What screws of the model can be replaced with the screws included in our kits ?

With the right screw kit for your model you can replace all standards screws that are used in your car . According to your model the kit includes screws of the (metric) sizes M2, M2.5, M2.6, M3, M4, M5 and M6 as well as nuts (normal, lock and flanged) and washers.
Not included in our screw kits are special parts and screws which do not originate from a keiner DIN or ISO standard. Therefore special screws, which are produced only for a certain model or a brand (e.g. with a special head) are not included.

 

What kind of screws are used for the kits ?

We only put screws in our kits which have a hexagon socket (Inbus / Allen). In comparison to slotted or crosshead screws hexagon socket screws give a much better torque transmission and thereby help not damaging the socket when screwing in.

 

I do not find self-tapping / self- cutting screws in my kit. Did you forget these ?

If so called self-tapping screws with a coarse thread are build in your model, we regularly replace these with high quality regular/standard threaded screws of the same type and size.
The screws do fit into holes which already have been used (but not bugged out !) and also into holes which have not seen a screw yet. Additionally you get a better fit with the fine thread screws in comparison to coarse thread, because of the different incline of the thread and thereby the higher thread area.

 

Of what kind of material are the screws manufactured ? What does A2 or 12.9 mean?

About stainless steel screws: The screws used in our stainless steel kits are made of A2-70 stainless steel , a cold worked metal, non-rusting stainless steel. Codes:

  • A = Austenitic structure
  • 2 = highly resistant to corrosion, partly acid resistant, chrom nickel alloy
  • 70 = minimum specified tensile strength Rm = 700 N/mm²

About high tensile steel screws: Hochfeste Our steel screws are made of alloys which are additionally tempered Stahl. The black surface originates from a treatment in a special solution which is applied to increase corrosion resistance. The numbers 10.9 and 12.9 give information on the strength of the steel. The first part is the minimum specified tensile strength and the second is the yield stress(in N/mm²)

For example a cylinder screw M3 x 12mm class 12.9:

The value 12 gives the minimum specified tensile strength. For this it has to be multiplied by 100. 12 x 100 = 1200
Therefore the minimum specified tensile strength is 1200 N/mm²

The yield stress or elastic limit is calculated by multiplying the first and the second value and then multiplying this with 10. 12 x 9 = 108 x 10 = 1080
Therefore the yield stress hast the value 1080 N/mm²

All of this means that a small M3 cylinder screw of 12.9 steel can withstand a permanent stress of 490 kg ! (1 kg = 9,81 N)
 

 

What is the advantage of Titanium screws made from Titanium grade 5 instead of Grade 2 ?

Because of the higher tensile strength of the screws it lasts longer when driving, but also when screwing them in and out. The Auf Grund der hohen Festigkeit hält die Schraube sowohl beim Fahren als auch bei der Montage wesentlich mehr aus. The risk of screwing up / destroying the hexagonal socket is lower in comparison to Grade 2 screws.

In the following table the differences between different kinds of steel and titan can be compared.

 

Tensile strength
(in N/mm²)

Yield point
(in N/mm²)

Lengthening

Density
(in kg/dm³)

Titanium grade 2
W.3.7035
min. 390  min. 250 min. 22% 4.51

Titanium grade 5
(Ti6Al4V) W.3.7165

min. 895 min. 828 min. 10% 4.40
Steel grade 8.8 min. 800 min. 640 min. 12% 7.90
Steel grade 10.9 min. 1000 min. 900 min. 9% 7.90
Steel grade 12.9 min. 1200 min. 1080 min. 8% 7.90

 

 

Are tools (wrenches) included in the kits?

Yes, in every screw kit the wrenches you need are included.
But the included wrenches should not replace high quality wrenches . We recommend tools from PB Swisstools. These tools do have high precision tips and provide optimal torque transmission not to damage the socket of the fastener.

 

What is the advantage of hexalobular / 6lobe / TORX screws ?

The hexalobular/TORX socket provides an optimal transmission of the torque. The Torx design allows for a higher torque to be exerted than a similarly-sized conventional hex socket head without damaging the head and/or the tool. Torx sockets were designed to prevent cam-out. Therefore the screws can be reused more often and can be used for more disassemblies and assemblies of your car !

Please notice: It is possible to cam-out TORX screws and tools ! Therefore it is absolutely required to use quality tools !

 (Further information on TORX can be found e.g. at Wikipedia )

 

Why are only screws starting from M3 included as 6lobe / TORX in the 6lobe / TORX kits ?

One reason for that is the maximum torque that can be overcome by the screw socket in comparison to the tool.
For hexagonal socket screws the maximum torque is limited by the durability of the screw head (when quality tools are used). To much torque leads to a worn out / cam-out socket
For hexalobular/TORX screws the torque transmisssion from tool to socket is better, because of the "star" design of the socket.
However this advantage is getting smaller with smaller getting screw sizes or rather exists not any more. We did not see an advantage in the 6lobe / TORX drive for screws smaller then M3 and did not produce them therefore. 

In Numbers:

  • M4 screws grade 10.9 can overcome a maximum torque of 4,4 Nm. Hexagonal screw drivers for M4 screws have a test torque of 6,6 Nm. 6lobe / TORX screw driver for M4 screws (T20) have a test torque of 10,5 Nm. Therefore the screws are "weaker" than the screw driver.
  • M3 screws grade 10.9 can overcome a maximum torque of 1,7 Nm. Hexagonal screw drivers for M3 screws have a test torque of 1,9 to 3,8 Nm (resp. countersunk or cylinder head). 6lobe / TORX screw driver for M3 screws (T10) have a test torque of 3,7 Nm. Therefore the screws are "weaker" than the screw driver.
  • M2 screws grade 10.9 can overcome a maximum torque of 0,56 Nm. Hexagonal screw drivers for M2 screws have a test torque of 0,53 to 0,82 Nm (resp. countersunk or cylinder head). 6lobe / TORX screw driver for M2 screws (T6) have a test torque of 0,43 to 0,75 Nm . Therefore the screws are "not weaker" than the screw driver.

As the socket/wrench size for set screws is about one to two sizes smaller then for headed screws, the described problem occurs already for set screws size M3. Therefore we did not produce set screws with 6lobe / TORX head

Certainly in our 6lobe kits all screws for your model are included !

As written in the product description the screws we do not have as 6lobe / TORX are included as screws with hexagonal socket. For almost all modells this is less than 10% of all screws.

 

Why are the M6 screws for big scalers (1:5, 1:6) included as 6lobe / TORX screws grade 8.8 galvanized and not as grade 10.9 ?

 

In short, because the quantity would have been to small to be produced extra.

Even in big scalers only a small amount of M6 screws are used. If we would produce them in grade 10.9, the production price would be exorbitant high because of the small quantity (3-6 Euro production cost per piece !).
As the maximum torque of M6 screws from grade 8.8 to 10.9 only increases from 14 to 16 Nm (approx. 15%), we guess that grade 8.8 also withstands. Therefore we resort to screws available at whole salers, keeping the price for big scalers reasonable.

 

How are the screws packed ? How does a screw kit look like?

The screws of a kit are sorted by length and diameter in a practical box made of shock-resistant plastics. Because of the thought-out sorting in several compartments of the box, it is easy to find the needed screw size.

Screw kits up to approx. 400 screws are ensorted in a small box with 6 compartments:

Example of a small screw kit


All kits with more than 400 screws are ensorted in a big box with 8 compartments:

Example big screw kit


All kits do have a label which gives information for what car the kit fits, the material and quantity of the screws and the order number.
Example of a Mugen MBX-6T:

Kastenaufkleber