A tool is designed which facilitates the forming of wire grids used in manufacturing strain gage grids. Flattening the grid wire by a cold working process produces a stabilized grid which can be readily handled for storage or shipment

Bonn, J. L.

Gardner, D. E.

English

NASA Technical Reports Server

FIGURE 1
Form Plate 
Hole 
Hole 
Jaw 
Jaw 
Press BI0 
Grid Wire 
Form Plat 
Receiver Pit
FIGURE 2
Receiver Plate 
Pins 
Grid Wire 
February 1965
	
Brief 65-10009 
NASA TECH 0 1 UN ^5 A^ 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
Forming Blocks Speed Production of Strain Gage Grids 
Compressed Grid
Leads
Cement 
Test Surface—	
Coat 
FIGURE 3 
The problem: Current strain gage manufacture 
involves the use of a jig to produce the desired 
grid configuration. The entire jig, holding the grid, is 
placed on the test surface while the grid is partially 
cemented to the surface and the jig is then removed. 
The procedure requires considerable skill and is time 
consuming. 
The solution: A wire grid-forming tool that is sim-
ple to operate, produces a stabilized grid which can be 
readily handled with reasonable care, and lends itself 
to production operation. 
How it's done: The tool, shown in figure 1, con- 
sists of two steel jaws, a steel form plate and a steel 
receiver plate, each of which has aligned pin holes, 
the holes in the receiver plate being slightly larger in 
diameter. Hard steel pins slightly longer than the 
depth of the form plate are pressed in the holes of 
the form plate so that they protrude slightly above it,
FIGURE 4 
giving the desired grid structure. The grid wire is 
then woven back and forth about these pins, forming 
the structure shown in figure 2. The formed grid 
with its supporting structure is then placed under a 
slight pressure. The degree of pressing of the gage wire 
is not necessarily critical but should be adequate to fix 
the grid form to a point where the grid may be han-
dled without permanent distortion of shape. The flat-
tening of the grid wire is a cold working process and 
the result of this operation is to produce a stabilized 
grid which can be readily handled with reasonable 
care for direct use, for storage or for shipment. Upon 
tool disassembly, the pins will protrude slightly be-
neath the bottom surface of the form plate, having 
entered slightly the larger holes in the receiver plate. 
By merely reversing the receiver plate, the tool is ready 
for the next grid forming cycle. Figure 4 shows one 
application of the finished grid. The test surface is 
lightly precoated with cement and the grid placed on 
this film and a cement cover coat applied.
(continued overleal) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern. 
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed ir this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19650000009 2020-03-11T17:16:36+00:00Z
Notes: 
1. The grid form may be widely varied by machining 
the appropriate components of the tool to the de-
sired contours. 
2. Quality strain gage grids have been thus formed 
from tungsten, platinum, nickel, and nickel alloys 
over a gage resistance range of from 50 to 500 
ohms. 
3. Inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio, 44135 
Reference: B65-10009
Patent status: NASA encourages the commercial 
use of this invention. It has been patented by NASA 
(U.S. Patent No. 2,991,671) and royalty-free license 
rights will be granted for its commercial development. 
Inquiries about obtaining a license should be ad-
dressed to NASA, Code AGP, Washington, D.C., 
20546.
Source: John L. Bonn and

Daniel E. Gardner
(Lewis-182) 
Brief 65-10009	 Category No. 05


Forming blocks speed production of strain gage grids

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