NP
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 +44 (0)1302 836012 sales@npfasteners.com
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NORTHERN PRECISION LTD
Accreditations Northern Precision Ltd operate a quality management system in accordance with ISO 9001:2008. The ISO 9001:2008 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.
Registered in England & Wales Company number 3275391
V.A.T Registration number GB 684 1384 17
NP
NORTHERN PRECISION LTD
Specialist Fasteners for Sheet Metal
+44 (0) 1302 836010
+44 (0) 1302 836012
Tel:
Fax:
sales@npfasteners.com
Quality
Service
Reliability
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Fastener is not fully seated
Problem Poor performance. Part falls out of panel.
Cause The fastener is not installed fully. You must ensure that the fastener is installed so that no knurling is visible or the head is flush with the panel. Solution Apply more force and or increase the length of stroke on the press so that the fastener is fully installed. The shoulder of the fastener should be in contact with the panel and the knurling should not be visible.
Fastener is not installed squarely
Problem Poor performance. Part falls out of panel.
Cause The punch and anvil faces are not and parallel or the panel was not held perpendicular to the anvil and punch during installation. Solution Make sure that panels are supported and held perpendicular to the punch and anvil. Punch and anvil faces must be parallel to each other.
Large gap
Problem Poor performance. Fastener installs off centre.
Fastener located incorrectly in hole resulting in side of hole shearing as fastener is installed. Limited holding power in pane.
Cause The hole is bigger than specification. Solution Make sure the hole is within specified tolerance. Ensure that the fastener is located squarely in the hole before applying pressure.
Problem Tight Threads. Fastener cracked after installation.
Shank protrudes through bottom of panel and is deformed by anvil.
Shank is cracked and threads are tight.
Fastener squashed and bulging sides
Fastener will not fully seat
Cause If you try to install a self-clinching fastener with the wrong shank length for the  panel, as the shank bottoms out on the anvil it will deform and crack. Solution You must use a part that is suitable for the panel thickness or ensure that the panel meets the minimum panel thickness requirement for the specific fastener.
Problem Poor performance. Part falls out of panel.
Hole has been countersunk to deburr the hole.
Cause Countersinking or chamfering removes material which is required during the clinching process. There will not be enough material left to displace and fully fill the clinch feature. Solution Do not remove any material by countersinking or chamfering the hole. The shoulder of the hole should be square. It is always preferable to install the fastener from the punch side of the panel.
Anvil
Punch
Cupped head
Punch is too narrow
Problem After installation the head of the stud, pin or standoff is cupped and does not sit flush with the surface of the panel. Cause The punch diameter is too small. Solution Use a punch with the correct diameter. The punch should be wider than the head of the fastener and ideally be the same diameter as the anvil to avoid panel distortion.
Anvil
Flat Punch
Material is displaced  into the anvil instead of fully filling the clinch feature because the anvil hole is too large.
Problem Torque-out or push-out performance of fastener is poor. Cause Anvil hole diameter is too large and is allowing  material to flow into anvil instead of the clinch feature, or incorrect chamfered anvil is being used. Solution Use an anvil with the correct diameter hole. Only use a chamfered anvil where appropriate.
Anvil
Punch
Problem Panel distorts when trying to install clinch studs in thinner panels. Cause No chamfer on anvil. In thinner panels a chamfer is required to accommodate the amount of material that is displaced during installation. Solution Use the correct anvil type for the fastener and panel thickness.
When installing our self-clinching fasteners, providing all technical requirements are met and installation instructions are followed, you shouldn’t have any issues. There are so many permutations of fastener type, size, panel material characteristics, hole preparation,  installation and tooling configuration that it is impossible to cover absolutely everything here. This is the reason we state that the performance figures given for our fasteners are offered as guidance only. Below are some of the most common issues encountered when installing self-clinching fasteners, along with the cause and solution to ensure a successful installation an optimal performance. If you are experiencing problems beyond the scope of this guide, please call our sales team for assistance.
Problem Tight threads, poor performance. Part falls out of panel.
Cause The panel is above the recommended hardness limit for the fastener. Solution For correct installation, self-clinching fasteners need to be harder than the panel material they are being installed into. You must pay attention to the maximum panel hardness limitation for the specific fastener type you are installing.
Fastener deformed, bulging sides and tight threads. Limited displacement of panel material.
SELF-CLINCHING FASTENERS SOLUTIONS TO COMMON PROBLEMS