Tek screws

[Exfarmer]

Looking for some advice.
Our house uses heavy RSJs as lintels across large bi folding doors.
I need to attach a screen to the underside of the lintel as I dare not put too much weight into the bi fold structure
I am having issues fixing to this , have got some tek screws but they keep shearing. So far I have got 3 holes and 3 sheared screws and a distinctly underimpressed wife
The weight is not great , about 4 kg but worry that grandson may choose to swing on it and do sone damage to the door frame.
Can anyone explain to a simplton like me about the correct tek screws for putting into the RSJ

 

[Fraserb]

Are they the fine threaded ones? I've never had much bother screwing those into raj's before.

 

[goodevans]

Have you tried a pilot hole

 

[Exfarmer]

Have tried a pilot hole, certainly easierto get them started, but still sheared off.
Wonder if I should drill bigger then 4 mm ( i think most teks are 5.5)
Can anyone recomend types, grades and or stockists.
Most of the wholesalers are talking box of 200 and that will leave me 198 left over

 

[Adeptandy]

Have tried a pilot hole, certainly easierto get them started, but still sheared off.
Wonder if I should drill bigger then 4 mm ( i think most teks are 5.5)
Can anyone recomend types, grades and or stockists.
Most of the wholesalers are talking box of 200 and that will leave me 198 left over

I always use the 5.5's and was pushing them through 4x2 yesterday into the steel frame of the farm shed ok with an 18v impact driver.

Always handy to spares for the future

 

[Steve welder]

As said above you need the fine thréad ones designed for heavy steel. Ordinary ones only good for about 3mm thick

 

[Banana Bar]

As said above you need the fine thréad ones designed for heavy steel. Ordinary ones only good for about 3mm thick

This

 

[bobk]

5.5mm screw , 5 mm hole , they won't fall out

 

[Still Farming]

Have you wood or steel tec screws?

 

[chickens and wheat]

Fine thread with longer than normal tip for the drilling

 

[chickens and wheat]

This but newer cleaner straighter

 

[Exfarmer]

thanks I know the screws are for steel but I they are coarse threaded which I sam sure is the issue and designed for thinner section.
many thanks for all the comments

 

[grainboy]

Why not drill and tap 6mm ?

 

[Exfarmer]

Why not drill and tap 6mm ?

it is possibly not the easiest places to get access to

 

[robbie]

There is different types as mentioned above. There is tin to wood(course) tin to tin(we call them (stitching screws), tin to plate(3mmish) and tin to steel amongst other variants. We've never had bother screwing to rsj's as long as you've got the right ones for the job.

 

[grainboy]

No more difficult than breaking tex screws,

 

[Nearly]

fine thread tecs, proper impact driver and try a bit of thin oil on the tec if you're heavy handed on the drill.

1/4" ratchet and 8mm socket will slow you down.

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[suffolksmallholder]

@Exfarmer, I pilot and tap. No breakages. I only use Dormer taps. End of. If you want to do-it-fast then I'll put money on breaking loadsa them.
SS

 

[designanddetail]

5.5 x 50mm 5/16” Hex Head Super Tek 7 Self Drill 4.00-18mm Evolution TSHW5.5-50-7 - Orbital Fasteners

Something like these you need nut probably shorter

 

[Andrew]

You should be fine with the correct Tek screws as others have posted.
If not try one of these:

VersaDrive® Impacta DrillTaps - Metric Coarse (301125)

VersaDrive®ÃŠ Heavy Duty Impacta-Drill Taps are an industrial metalwork or fabrication tool for drilling and tapping heavy steel in one easy operation. Order today!

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