How to correctly select and use UCAN U-DRILLS® Self Drilling Screws

The purpose of this video is to provide our customers with a comprehensive understanding of U-DRILLS® as well as their correct application and installation.
For more information visit www.ucanfast.com

[@tommercik]

Thanks for this knowledge article - very timely, given my current challenge. Some questions: are self-drilling screws "one shot" affairs, namely once drilled in, they should not be backed out in order to add something to the screws (like a hook or piece of wood or metal) to then re-attach into the original drill hole? In the same vein, when attaching metal pieces to metal, do both layers of metal have to be self-drilled and thus both tapped, or can the first piece be pre-drilled slightly larger in screw diameter (using an ordinary metal drill), then held in place by self-drilling into the holding piece? I'll be working at height in confined quarters so any advance work I can do in the workshop before tackling the final install on-site would be very beneficial. Thanks in advance... Tom

[@ucanfast]

Hello,
Thank you for your interest in our products.
Yes, self-drilling screws are "one shot" affairs, namely once drilled in, they should not be backed out in order to add something to the screws (like a hook or piece of wood or metal).
When attaching metal pieces to metal, there are two options:
both layers of metal have to be self-drilled and thus both tapped - the total thickness of both pieces MUST not exceed the drill capacity of the screw.
the first piece can be pre-drilled slightly larger in screw diameter (using an ordinary metal drill), then held in place by self-drilling into the holding piece.
In this case, the drill capacity of the screw will only be for the second (base/holding) metal piece.
Advice: Choosing the length and size of the screw is very important. The correct length of the screws for the job is = Total thickness of both metal pieces + 3 thread lengths + the drill point.
e.g. If you would be using a #12-14, #3 point screw, the total thickness of the two plates is 3 mm + 3 thread lengths (5.5 mm) + drill point (6.5 mm) then the length of the screw should be at least (3 + 5.5 + 6.5) = 15mm…UCAN sells a 5/8 length screw for this.
Please note that #3 screws can drill MAX 1/4".

[@tommercik]

Thank you, very helpful response. Not that it will make my "at height" job any easier :)@@ucanfast