Warning for Biltema's decking screw

[Dan_Johansson]

You are talking to a mechanical engineer who has studied strength of materials and fastener elements etc. at fairly high levels.
It's clear that the market is full of screws, with different strengths at different prices.
What exactly are you trying to say?

That price is the most important thing for you?

Interesting that you played the engineer card... And then you bring the market into it...

If the screw could be manufactured, and there was a demand for it, it would be on the market... Feel free to link to the screw and I'll buy a pack and test it...

 

[Violina]

Interesting that you played the engineer card... And then you mix in the market with it...

If the screw could have been manufactured, and there was a demand for it, it would have been on the market... Feel free to link to the screw and I'll buy a pack and test it...

It's because he thinks that "engineer card" is like some kind of joker when discussing this stuff...

It's more like the Old Maid in practical matters rooted in user error

 

[vectrex]

But honestly. How wrong can you really go when fastening a decking screw? Sure, when my 6-year-old son has had a go at screwing in some decking screws, both the bits and the screw head can be a bit mangled afterward, but the screw's durability hasn't really been compromised by his handling. No, I don't buy handling errors.

I have no experience with Biltema's screws (I've used Heco and Essve) and screws generally only break for me when I'm screwing into ash, oak, or similar, never in soft coniferous wood. If there's something I'll change in the future, it's to avoid C4 and use at least A2 stainless. C4 rusts within just a few years here on the west coast (despite living about 10 kilometers from the sea).

 

[Violina]

But honestly. How wrong can you really go when driving in a decking screw? Sure, when my 6-year-old son has driven in some decking screws, both bits and screw heads can be a bit mangled afterward, but the screw's strength has hardly been compromised because of his handling. No, I don't buy the user error.

I have no experience with Biltema's screws (I have used Heco and Essve), and screws generally only break for me when I'm screwing into ash, oak, or similar, never in soft coniferous wood.
If there's something I'll change in the future, it's to avoid C4 and go with at least A2 stainless. C4 rusts in just a few years here on the west coast (despite living about 10 km from the sea).

The chance that your 6-year-old is strong enough to tighten a screw so much that it breaks, I think, is quite low.

The problem arises when full-grown men either use the wrong type of tool when driving in the screw or drive it in too far (many times to avoid having to tighten them again if the screws pop up).

Or it might be that they haven't built/constructed properly and have too much movement in the structure, causing the screws to break.

 

[Alfredo]

Especially when you consider the fact that people who actually know how to proceed when driving a screw rarely have the mentioned problem of every other screw snapping.

But honestly. How wrong can you really go when driving in a deck screw?

I also wonder what you can do wrong? If we "for the moment" forget about impact drivers and their potential impact, what is right and what is wrong?

As I see it, you can basically only adjust two parameters. Driving speed and depth. I've never really thought about speed more than just using the speed that works without losing control? Is it important to use the right speed, and what is the right speed?

When it comes to depth, you drive the screw flush with the decking or slightly below, right? You don’t want "protruding" screw heads or "holes" from "over-countersunk" screw heads. So, how do you make mistakes?

I've driven quite a bit of pine and my experience is that there's definitely a difference between different deck screws. In some cases, a double-digit percentage of the screws have snapped after a year. However, I've almost never experienced screws breaking while driving, unless you manage to hit a rock-hard knot or something similar.

 

[Alfredo]

The chance that your 6-year-old is strong enough to tighten a screw so hard that it breaks, I think, is quite low.

Normally, not much strength is required to maneuver the trigger on the screwdriver.

 

[Jonas Persson]

No, I don't think so, that's the whole point

Neither did I, just added to your reasoning

 

[Huddingebo]

The only thing I tried to explain, so that those who are not so familiar with screws won't buy the wrong kind, was that A2 and A4 do not indicate tensile strength.

Some people think it's some kind of quality mark guaranteeing a good screw when in fact it only indicates how resistant the screw is to corrosion.

My experience is that there is quite a difference in tensile strength between different brands.
It is often reflected in the price but not always.

Decking swells and dries frequently and puts stress on the screw.
Wood is more or less soft, if the screw breaks when it's pulled in 1mm below the wood surface (minimum on fresh ntr decking that dries out after a while), then it's a bad screw with poor tensile strength.

The screws I have the absolute best experience with are Heco.
Biltema has uneven quality, likely manufactured in China with uneven quality of the base material.

In the industry, I have mostly worked with metric screws in hot environments but the principles are the same with yield limits, breaking limits, hardening, corrosion classes etc.
It is often difficult to get the correct data on.
e.g., yield limit on "no name" screws.
Stainless steel GENERALLY has a lower breaking limit and stainless steel is not a guarantee that the screw will withstand the temperature in, for example, an exhaust manifold; there are non-stainless alloys that with the right treatment are significantly better in that regard.
(that's also a common myth)

 

[Huddingebo]

Again, does anyone seriously believe that, for example, Biltema sells screws year after year that break?

Of course, there are bad examples or possibly a whole batch.

About five years ago, Byggmax sold their own screws from China in blue boxes. They were junk, had a box with 6x120, and they were crooked. I haven't seen their own brand since then, only Heco.

No company with a store in Sweden sells junk, because it wouldn't work as customers would complain. Poor screws might be sold on Chinese websites where consumer laws don't apply and which have millions of other customers to trick.

Evidently, Biltema sells wheel bearings that wear out year after year after 1-3 years.
Uneven quality is their standard.

 

[Violina]

Normally, it doesn't require much strength to maneuver the trigger on the screwdriver.

No, but to hold against the screwdriver/make sure that the power is transferred to the screw..

All the mangled bits and screw heads are proof that maybe that part is failing?

 

[Violina]

Evidently, Biltema sells wheel bearings that wear out after 1-3 years year after year. Uneven quality is their standard.

Or 1 month

 

[Anonymiserad 282191]

Uneven quality is their standard

I really agree with that, a pure lottery many times

 

[Leif i Skåne]

Check post #30 and the link below
https://www.byggahus.se/forum/threads/problem-med-trallskruv-som-gar-av-ejot.317311/

after discussions in 2018, ESSVE has backed off!

From this year's brochure in 2021, ESSVE only recommends stainless steel screws A2 or A4 for outdoor decking!!!

Coated iron screw C4 is only intended for indoor decking, under a roof that does not move!

 

[Jonas Persson]

It is proven that Biltema sells wheel bearings that wear out after 1-3 years. Uneven quality is their standard.

I don't think it's quite the same thing. Wheel bearings are expensive to manufacture with good quality and I would claim that Biltema's are much cheaper than the original. The decking screws have a similar price with many other brands.

 

[A-Man_08]

What!!
Don't you pre-drill?