Venetian blind into window recess - metal lintel

[marksgotnoidea]

Im having a nightmare! I need to fit a venetian blind into the window. As its a large window I need to fix the brackets into the top surface as there is also a middle support bracket. 1cm into the plaster you hit a metal lintle. Ive read to use metal drill bits - i tried but they hardly touched it - possibly not good quality. I have no idea of a lintles construction - How thick is the metal? When i get through it whats on the other side? What fittings should I use? The blind came with screws and wall plugs. Ive no idea what size bit/plug to use - i was trying a 5.5mm drill bit. My colleague leant me a SDS plus drill - but they have masonry bits so I didnt try it - and the head of the drill was massive making it harder to get the holes up to the edges of the window. Can anyone help please?

 

[Diyisfun]

A good quality drill bit should get through it.
You need a self tapping screw to secure it.
Whats behind the steel doesnt matter.

 

[marksgotnoidea]

Hi - Thanks for the prompt reply! Im not sure what size bit and screw to use? E.g. if i use a 5.5mm HSS drill bit should i buy no 6, 8 or 10 self tapping screws? I tried to locate a table to show you the relationship between bit size, wall plug size and screw size.
M.

 

[Diyisfun]

http://www.aaronsself-tappingscrews.com/free_table_of_recommended_drill_sizes.htm

Use No 8 as minium, depends on weight & how good a fixing you get.

Looks like the dimension are in inches, so dont forget to convert.

 

[marksgotnoidea]

Thanks - Had a look and didnt understand table. If I use a no 8 bit what size self tapper in metric is this? M.

 

[Diyisfun]

You look at the screw size, then look at what you are drilling into, ie thin or thick and is in inches.
So
Thin = 3.45mm drill
Thick = 3.57mm drill
Its better to drill to small, if the screw is difficult toscrew in, use the next drill size or you could break the screw.
Happy drilling