Contact us
You can contact us using any
of the methods below.
Unit 3 Durham Lane
Armthorpe
Doncaster
South Yorkshire DN3 3FE
England
+44 (0)1302 836010
sales@npfasteners.com
All rights reserved
© Northern Precision Ltd.
NORTHERN PRECISION LTD
Accreditations
Northern Precision Ltd operate a quality management
system in accordance with ISO 9001.
The ISO 9001 standard is recognised worldwide and
you can be assured of the benefits of working with a
certified company knowing that our management
systems are constantly assessed and improved.
Regulatory
RoHS|WEEE Compliance
REACH Compliance
Conflict minerals
statement
Environmental Policy
Opening Hours
Mon - Fri 08:00 - 17:00
Registered in England & Wales
Company number 3275391
V.A.T Registration number
GB 684 1384 17
Self-Clinching Fasteners
Broaching Fasteners
Arnold & Shinjo Fasteners
Rivet Bushes
Rivet Nuts
Weld Fasteners
Spring Steel Fasteners
Blind Rivets
Inserts for Plastics
Inserts for Stone, Solid
Materials, Composites &
Sandwich Panels
Crown-Nuts
Fast-Con
Installation Equipment
Turned & Cold Formed
special parts made to order
Bespoke fastener design &
development
Fastener & Application
testing
Technical support
ISO 9001
RoHS|WEEE Compliance
REACH Compliance
Conflict minerals
Environmental Policy
Keep-Nut Guide
Keep-Nut Flush
Keep-Nut Flanged
Keep-Nut Stud
Master-Plate Guide
Master-Plate Stud
Master-Plate Blind Standoff
Master-Plate Through
Standoff
Master-Plate Through Nut
Deform-Nut Guide
Deform-Nut Type TC
Installation Method & Performance
Prepare hole in base material
to correct specification.
Verify hole diameter using
Go/No-Go gauge. Check hole
depth against reference line
on Go side of gauge.
To ensure correct installation
it is recommended that a
threaded mandrel is used.
Fully screw on the insert and
drive into the hole.
Unscrew the mandrel and the
insert is installed and ready
for use.
Example assembly
Material
Granite 20mm
Marble 20mm
Travertine 20mm
Fibre cement (high density) 12mm
Fibre cement (high density) 10mm
Fibre cement (high density) 8mm
HPL 12mm
HPL 10mm
HPL 8mm
Corian 12mm
Corian 10mm
Agglomerate stone 15mm
Tempered glass 5mm
Keep-Nut
Type
KN4 M6 H8.5
KN4 M6 H8.5
KN4 M6 H8.5
KN4 M6 H8.5
KN4 M6 H8.5
KN2 M6 H6
KN4 M6 H8.5
KN4 M6 H8.5
KN2 M6 H6
KN4 M6 H8.5
KN2 M6 H6
KN4 M6 H8.5
KN1 M4 H5
Average pull-out
load on a single
insert (Kg)*
490
385
225
275
239
125
541
611
270
484
295
305
75
Comparison of results from tests carried out on a range of materials.
* Tests were carried out under laboratory conditions. Pull-out figures are
indicative only and are offered for guidance purposes. It is recommended
that you undertake your own tests in the actual application panel material.
Advantages
•
Simple hole preparation
•
Quick installation
•
No need for resins or adhesives
•
Radial force is produced only while
the insert is under tensile load.
The crowns spread the load into
the parent material, allowing large
loads to be carried
•
Thread stops before end of insert,
avoiding extraction as a result of
the use of an excessively long bolt
Material & Finish
Bush: Stainless Steel
Crown: Stainless Steel
Body: Plastic
Part Number Examples
Part number is made up as follows:
(Type code) (Thread code) (Height code)
For example:
KNF1 M4 H5 (Keep-Nut Flanged 1 crown M4 5mm overall height)
KNF2 M5 H6 (Keep-Nut Flanged 4 crowns M6 8.5mm overall height)
KNF4 M6 H8.5 (Keep-Nut Flanged 4 crowns M6 8.5mm overall height)
Downloadable Data Sheet
Back
Dimensional
M4
KNF1 M* H5
M5
KNF2 M* H6
M6
M5
7.0
7.5
M4
5.5
4.5
KNF4 M* H8.5
M6
M5
10.0
M4
7.5
M6
Info
Keep-Nut® is a press-in threaded insert that utilises a mechanical anchoring feature, to provide permanent threads
in panels made of marble, granite or other stones, as well as composites, carbon, Corian®, HPL, glass and others
solid surface materials.
Keep-Nut is manufactured in stainless steel and consists of a threaded bush, a set of toothed spring washers
(crowns), and a plastic ring holding the parts together. Available in different lengths, with or without flange, to fit
several different panel thicknesses, Keep-Nut can be installed quickly since the user simply needs to drill the
material with the correct hole diameter and press-in the insert. Keep-Nut can also be customised with different
versions and sizes, to meet specific customer requirements.
The Keep-Nut insert is specifically developed to fasten ventilated façades, wall-coverings, décor and interiors,
furniture, kitchen and sanitary elements, as well as a variety of other applications.
Keep-Nut inserts have several advantages compared to other fasteners for stone and solid materials. The
preparation needed is just a cylindrical hole – an undercut hole is not required – which means that standard tools
can be used. In addition, assembly by pressure is quick and easy and does not require use of any additional resins
or adhesives. Keep-Nut inserts can be used for hidden assemblies without any protruding parts, facilitating the
handling and installation of a variety of materials.
In use, the crowns are engaged by axial force, acting radially against the hole wall, effectively permanently locking
the insert in place. In addition, the internal thread does not run completely through the bush, which prevents
extraction as a result of the use of an excessively long screw.
Keep-Nut is a trademark of SPECIALINSERT S.r.l., Corian is a trademark of E. I. du Pont de Nemours and Company.
(Type) (Thread)
(Height Code)
D1
Thread
S Min.
Thickness**
H1 Thread
Depth
D2
Hole Ø
±0.2
12
12
12
4.5
5.5
8.0
L2 Hole
Depth
+1.0
No. of
Crowns
1
2
4
Installation
Force (kN)*
0.2
0.4
1.0
Pull-Out
Force (kN)*
0.5
1.7
2.9
*Figures are indicative only and are offered for guidance purposes. ** Minimum material thickness is related to
parent material characteristics. It is recommended that you undertake your own tests in the actual application panel
material.
TYPE KNF
KEEP-NUT®
FLANGED
