Pin locking technique for flush fasteners retains a screw under dynamic conditions when self-locking or lock wiring devices are not practical. Spring pin is counter sunk through one side of the screw head into the component to form a flat surface

Totah, R. S.

English

NASA Technical Reports Server

.August 1969	 Brief 69-10282 
NASA TECH BRIEF 
NASA Teàh Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Countersunk Headscrew Retainer 
Spring Pin Installed 
Through Screw Head 
Countersunk Head Screw Retainer 
The problem:
	 How it's done: 
Retaining a screw (under dynamic conditions) 
when the use of self-locking devices is not feasible and 
lock wiring provisions cannot be used because a flat 
surface is desired. 
The solution: 
A pin locking technique for flush fasteners.
In an environment where countersunk head screws 
cannot be held by either self-locking inserts or lock 
wiring, a practical solution is the use of a spring pin. 
A hole is drilled through one side of the screw head 
and into the component and the spring pin is inserted 
to form a flat surface. A spring pin installed in this 
fashion performs adequately under dynamic condi-
tions.
(continued oerIeaI) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000282 2020-03-16T17:46:52+00:00Z
Notes: 
1. The technique described in this NASA Tech Brief 
should be of interest to fastener manufacturers and 
personnel working in the machinery, aircraft, auto-
motive, and aerospace industries. The concept is 
new in that it describes a method of retaining a 
countersunk head screw in a tapped blind hole 
while maintaining a flat surface.
2. No further documentation is available. Inquiries 
may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B69-10282 
Patent status: 
No patent action is contemplated by NASA. 
Source: Raymond S. Totah of

North American Rockwell Corporation

under contract to
Marshall Space Flight Center
(MFS- 1648 1)
S 
Brief 69-10282	 Category 05


Countersunk headscrew retainer

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