Only for professionals

B 251 

RIPP LOCK® self-locking screws
Material: Steel | Surface: zinc-plated

Diameter (d)

Length (l)


For further information please contact us.
Item no.: W251100VZ820


Read on Hide
Item no.: W251100VZ820
Böllhoff standard 251 | Steel | Strength class 100 | zinc-plated | Cr (VI) - free | metric thread

The RIPP LOCK® self-locking screws are reliable fasteners for securing screw connections against loosening. The preload force is maintained even under high dynamic loads. With RIPP LOCK®, the screws have a special mechanical securing effect against automatic loosening of the connection. This is created by radial ribs that act on the component over the entire contact surface. During assembly, the radial ribs are impressed into the respective mating part by the applied preload force. The resulting form fit prevents the connection from turning loose. Additional safety devices, washers and lock washers are not required. The component surface of even sensitive materials is protected.

• Reliable anti-rotation device
• Preservation of the preload force even under high dynamic loads
• Saves washers, spring washers or other additional safety devices

Dimension: M8 x 20

technical details

Read on Hide
a max. 3,75
Application Joining by bolt, joining by screw
b 28
Cr(VI) Note Cr(VI)-free
d2 max. 9,4
d2 min. 9,2
dc max. 17
dc min. 16
Diameter (d) M8
dk max. 14
dk min. 13
e min. 6,86
Flange/washer with flange
Force application Hexagon socket
Head shape Cylinder head with flange
Installation method Screw into place with tool
k max. 8
k min. 7,64
l max. A 20,42
l min. A 19,58
Length (l) 20
Material Steel
Pitch (P) 1,25
Risk hydrogen embrittlement
RoHS conformal
s 6
s max. 6,14
s min. 6,02
Surface zinc-plated
Thread type Metric thread
Tool size SW 6


You can download CAD-files from our catalog on partcommunity: To Böllhoff partcommunity
Title Language Version File Download
Data sheet: Technical information and dimensions of the product English 02/2023 129.76 KB / PDF
Fastening and assembly technology: Products and services English 1180/21-V1-EN (WBH) 8.79 MB / PDF
Böllhoff bulletin: Changeover to Cr6+-free protective zinc layers for fasteners English 1622/15.02 894.98 KB / PDF
RIPP LOCK® screw lock: Efficient and secure English 8210/21-V1-EN (WBH) 1.03 MB / PDF


This might also be of interest to you


General questions:
Phone: + 36 22 511 018

You come from another country? Here you can find further contact persons.