Screws for trunking lid

[AdamSmith86]

Hi all,

I was hoping to get some advice on which screws would be best for fixing the lid to some 50mm galv trunking. I am using Legrand trunking and they supply packs of turnbuckles but I am not sure they will be suitable for some smaller lengths of lid. I remember using self drilling screws years ago whilst working for someone but can not find anything online that is sufficiently short with a small diameter. I drilled them through the front of the lid and in to the lip of the trunking behind. My main concern with screws is that there will be a sharp point protruding in to the trunking which could potentially damaged the cables. Would it be wise to avoid screws all together?

All help much appreciated.

 

[snowhead]

You can get self tappers with blunt points, like these, they're what's used on electrical panel covers.
May need to find No.8 not No.10

https://www.ebay.co.uk/itm/Pack-50-...rews-10L142-/291106658250?hash=item43c74f17ca

 

[mattg4321]

Or tap an m3.5 or m4 thread into the lip of the trunking

 

[AdamSmith86]

You can get self tappers with blunt points, like these, they're what's used on electrical panel covers.
May need to find No.8 not No.10

https://www.ebay.co.uk/itm/Pack-50-...rews-10L142-/291106658250?hash=item43c74f17ca

Good call, thanks for that. Have ordered some 4’s and 6’s, will see what works best. Taking bets now on how many drills bits I’ll go through when making the pilot holes

 

[Lucien Nunes]

I normally use Taptite screws:
Taptite screws at Barenco

Unlike a traditional self-tapper, they form a normal metric thread in the hole e.g. M3.5, not as accurately as threading the hole with a tap, but they run in and out well enough and are strong. It is important to drill the correct diameter hole as they are not as forgiving as a basic S/T.

 

[telectrix]

2nd vote for Taptite.

 

[Marvo]

The self drilling screws go under the name of 'Tek Screws' where I am. The larger ones come as a hex head but they also do little philips head ones as well.

I'm not sure they're ideal for securing trunking lid though, if they self drill through sheet steel they'll also self drill through PVC cable sheath.....

 

[freddo]

I often use M4 nutserts, and screws that are not longer than them when fitted, so no risk of cable damage. Being a full threaded insert means the screws can be removed and reinserted many times without the hole becoming damaged.

 

[shelleysingh]

I often use M4 nutserts, and screws that are not longer than them when fitted, so no risk of cable damage. Being a full threaded insert means the screws can be removed and reinserted many times without the hole becoming damaged.

Thank you. It worked!