Can the point be cut off a self-drilling fastener once it has been installed?
- Read time: 2 minutes
- Date: 24 Jun 2021
- Flat Roofing
- Living Roof
- Rainscreen & Façades
- Sheeting & Cladding
It is normal for the drillpoint and a portion of the thread of a self-drilling fastener to protrude beyond the substrate once installed. This is to ensure that there is adequate thread engagement with the substrate. In some circumstances, this can cause concerns around health & safety or appearances.
We strongly recommend that self-drilling fasteners are not cut or tampered with in any way once they have been correctly installed. Cutting, cropping, filing, or modifying fasteners can reduce their pull-out performance, compromise their corrosion resistance and invalidate the warranty.
It is therefore important that the right length of fastener is selected for the application as this will minimise the amount of protrusion.
For more information, read our guide on how to select the correct length fastener
If fasteners do protrude, an alternative to cropping or cutting is to install a plastic ‘thread protector’ to the visible part of the protruding fastener.
Are there any circumstances where self-drilling fastener points can be cut or cropped?
Self-drilling fasteners used to secure build-ups into light section steel, aluminium or timber substrates should never be modified once installed.
Where it is absolutely necessary to reduce the penetration length of the fastener, cutting or cropping should only be considered where the steel substrate is at least 6mm thick. When removing the excess, do not apply ‘lever’ force to the fastener, so avoid sawing. Instead, use bolt croppers or a cutting or grinding wheel.
If carbon steel fasteners are being used, the cropped end of the shank should be painted to protect the fastener from corrosion.
