Concrete screw breaks during installation

[Jörgen_35]

I will screw a load-bearing beam into a concrete pier. I bought these screws after a recommendation at the hardware store: https://www.beijerbygg.se/privat/sv...betongskruv/betongskruv-fbs-ii-us-cp-ultracut

Dimension 6 x 100. Drilled a 6 mm hole as instructed. The screw goes in a few turns then becomes very tight, and when I applied more force, it simply broke. Is a larger hole needed or what could otherwise be wrong?

 

[Gooli]

To screw into concrete, a high precision of the drill size is required. I should have used an expander bolt. Much cheaper too, if you buy from the right places.

 

[Gooli]

None of the screws you linked to are for 6mm holes. Do you really have screws for 6mm?

 

[Fotografen]

The screws you link to are available in 8-10-12 mm, not 6 mm. I have no experience with these, someone with experience may comment further.
I would have used expanderbult.

 

[Jörgen_35]

It is 6 x 100. Clearly stated on the skull and also the box. I use expander instead. Here is the correct model: https://www.beijerbygg.se/privat/sv...etongskruv-fbs-ii-6x100-45-us-100st-007034323

 

[Matti_75]

Just 6mm can be a bit tricky. I always use a 1/4” drill for these. But I've never experienced them breaking. What kind of drill bit do you have and do you clean the hole sufficiently and drill deep enough?

 

[Superkewl]

When you're putting them in, do you use a drill or an impact wrench? I always find these easier with an impact wrench than a drill.

 

[jonaserik]

Load-bearing beam 45 X ?, the expander should be long enough so that the inner part with the thread is about 2 cm into the hole. This is because it will creep out about 1 cm when the nut is tightened to grip the hole. Make sure it has a long thread so it can be retightened. It's advisable to have the nut at the edge when it's driven in, to prevent the thread from being deformed. Additionally, drill the load-bearing beam first, clamp it in place, and then drill through the holes in the beam. Drilling the post first and then trying to level the load-bearing beam is bound to succeed.

 

[snaggletooth]

Worn drill?

 

[Jörgen_35]

When you're putting them in, do you use a drill or an impact wrench? I always find these easier with an impact wrench than a drill.

Ratchet wrench, it was a hexagonal head 😬. The drill bit was new, though from Jula. It'll have to be tried-and-tested expanders instead.

 

[YuGi]

I have similar experience with concrete screws that I also bought on recommendation from the hardware store. Had to be quite careful when screwing. About 15% or so broke, so it wasn't completely useless, but next time I'll probably go with expanderbult.

 

[MagHam]

It seems like the casting mold for the concrete is an eternit pipe. Personally, I'm not hysterically afraid of asbestos (as some are) but it might be a good idea not to disturb the surface too much.

 

[A76261]

Possibly a silly answer, but is it not lättbetongskruv you've got?

 

[Isakare]

A. Drill deeper than the screw's length, at least one cm more.
B. Blow out the hole thoroughly, preferably with compressed air.
C. Good drill bit, preferably Hilti with 4 cutting edges that is not worn.
D. Use an impact driver and stop immediately if it comes to a halt.
But preferably, use an expander instead, it is 100 times better, personally, I hate concrete screws.

 

[Klass0n]

The only time I snapped a concrete screw was when I hadn't drilled deep enough.