Hello everyone, I am currently looking into the topic "Which screws are good?" and would like to hear your experiences and recommendations.
I am less interested in basic wood screws and more in a well-founded selection for different applications—such as mechanical engineering, metalworking, or outdoor use. Strength, corrosion resistance, and good workmanship are important to me.
Which materials do you personally recommend for screws, and are there specific types you find better suited for certain applications? I am also interested in questions about surface coatings and possibly standards or quality classes. Thanks in advance for your input!
I am less interested in basic wood screws and more in a well-founded selection for different applications—such as mechanical engineering, metalworking, or outdoor use. Strength, corrosion resistance, and good workmanship are important to me.
Which materials do you personally recommend for screws, and are there specific types you find better suited for certain applications? I am also interested in questions about surface coatings and possibly standards or quality classes. Thanks in advance for your input!
For most metal applications, I recommend stainless steel A2 screws. They are affordable, do not rust, and have good strength. For higher loads, use A4 stainless steel. I would only use galvanized screws indoors, as the coating deteriorates quickly when exposed to outdoor conditions.
Your question is quite extensive, so I will try to provide a more detailed answer.
First of all, it depends heavily on the intended use: For mechanical engineering, screws with defined strength classes are particularly important, such as 8.8, 10.9, or 12.9 (according to ISO 898-1). Only these guarantee the necessary tensile strength and elasticity. In metal construction or steel structures, galvanized or hot-dip galvanized screws are often required, as good corrosion protection is essential there.
Regarding materials: Stainless steel A2 (also called V2A) is an austenitic stainless steel that is corrosion-resistant at room temperature but can be susceptible to pitting corrosion in chloride-containing environments. A4 stainless steel (also called V4A) contains additional molybdenum, which significantly increases corrosion resistance in salty environments – making it ideal for outdoor use or maritime applications.
When it comes to outdoor applications, choosing the right surface treatment is also important: Hot-dip galvanizing lasts longer and is more uniform than electro-galvanizing, which is often overlooked in cheaper products.
I would also recommend paying attention to standard certification when purchasing and using only screws from recognized brands or manufacturers, as their properties are reliably documented and production quality is controlled.
One more question: Which exact materials and loads do you want to join? Especially in mixed connections of metal and wood or metal and plastic, specialized screws are often advisable, such as screws with partially threaded shanks or special thread geometries.
First of all, it depends heavily on the intended use: For mechanical engineering, screws with defined strength classes are particularly important, such as 8.8, 10.9, or 12.9 (according to ISO 898-1). Only these guarantee the necessary tensile strength and elasticity. In metal construction or steel structures, galvanized or hot-dip galvanized screws are often required, as good corrosion protection is essential there.
Regarding materials: Stainless steel A2 (also called V2A) is an austenitic stainless steel that is corrosion-resistant at room temperature but can be susceptible to pitting corrosion in chloride-containing environments. A4 stainless steel (also called V4A) contains additional molybdenum, which significantly increases corrosion resistance in salty environments – making it ideal for outdoor use or maritime applications.
When it comes to outdoor applications, choosing the right surface treatment is also important: Hot-dip galvanizing lasts longer and is more uniform than electro-galvanizing, which is often overlooked in cheaper products.
I would also recommend paying attention to standard certification when purchasing and using only screws from recognized brands or manufacturers, as their properties are reliably documented and production quality is controlled.
One more question: Which exact materials and loads do you want to join? Especially in mixed connections of metal and wood or metal and plastic, specialized screws are often advisable, such as screws with partially threaded shanks or special thread geometries.
I would like to address a point from the third post and take a somewhat critical look at it, as it is often recommended to use only stainless steel for outdoor applications.
That is true, but the cost of A4 stainless steel can be significantly higher. In my experience, for many applications, a high-quality hot-dip galvanized screw with appropriate thickness and, if necessary, additional coating is completely sufficient without blowing the budget.
Furthermore, it is worth critically examining whether all parts that need to be rust-free necessarily require stainless steel – often it is only a matter of appearance or minimal corrosion prevention.
I believe a more detailed analysis of the requirements would be useful before blindly following the “stainless steel is inherently better” approach. Are there any specific examples where the use of A4 stainless steel was absolutely essential in your projects? What alternatives have you considered?
kaubi schrieb:
A4 stainless steel (also V4A) contains molybdenum, which greatly increases corrosion resistance in saltwater environments.
That is true, but the cost of A4 stainless steel can be significantly higher. In my experience, for many applications, a high-quality hot-dip galvanized screw with appropriate thickness and, if necessary, additional coating is completely sufficient without blowing the budget.
Furthermore, it is worth critically examining whether all parts that need to be rust-free necessarily require stainless steel – often it is only a matter of appearance or minimal corrosion prevention.
I believe a more detailed analysis of the requirements would be useful before blindly following the “stainless steel is inherently better” approach. Are there any specific examples where the use of A4 stainless steel was absolutely essential in your projects? What alternatives have you considered?
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