The self-tapping screw and self-drilling screw are frequently used in roof solar mounting structure. Both of them are easily confused by people. Today we’d like to introduce these two screws to you for your better understanding about what you should choose for your roof pv mounting systems.

1.The big difference that we can directly see is the tip on each screw is different. This is a great way to identify them from each other.

*self-tapping screw (which is with pointed tip)

*self-drilling screw (which is with drill tip)

3.Regarding material
Normally the self-tapping screw is Dacromet steel Q235, self-drilling screw is Stainless steel 410.
But there are some clients require SUS410 for the self-tapping screw as well, so it’s customized once the quantities meet the MOQ requirement.
4.Regarding gasket
We have plastic gasket and steel & EPDM compound gasket for choice.
5.Regarding dimension
We have 5.5x25mm, 6.3X25mm, 6.3x75mm, 6.3x80mm, 6.3x100mm, etc. Dimensions.
6.Application on pitched roof
Self-drilling screws can drill through metal. Self-tapping screws cannot drill through metal but require a pilot hole. Generally the self-tapping screws are widely used with stainless steel solar hooks for tile roof and aluminum L brackets for metal roof, the self-drilling screws are mainly used for metal roof only.

For any inquiry for solar panel mounting systems, please feel free to contact us, E-mail: sales@artsign.net.cn, Whatsapp / Wechat Skype: +86 18030235875, thanks.