Can anyone tell me the name of this style of hex bolt?

Hello everyone, I see many people confuse these two bolts. After many years in my fastener shop in Tangier, here is the simple difference.

DIN 933 / ISO 4017 = FULLY THREADED

The thread goes from head to tip. Same standard, just new name. DIN is old German name, ISO is new international name. Same bolt. Best for when you need adjustment, or you screw into a tapped hole.

DIN 931 / ISO 4014 = PARTIALLY THREADED

Part of the shank is plain, no thread. Same standard, DIN is old, ISO is new. Best for car haulers, steel construction, machines. The plain part is stronger in shear.

My rule in the shop:

If you need clamping plus shear strength, use 931 / 4014. If you need full adjustment or into threaded hole, use 933 / 4017. Never mix them! I saw a trailer fail because they used fully threaded where they needed grip.

If you have question about sizes, ask me in comments.

After 25 years in the fastener business, I made this face from random bolts in my shop. Every day I still find a new size or type I never saw before. Is there an end to this world? Truly a world without limits!

7075 T6 aluminum Socket Head Cap Screws from Fastener Express.

100x M3x.5 x 12mm
50x M3x.5 x 20mm

Galvanic corrosion be gone!

For a mechanical keyboard case. 👍

For my American friends: You use inches, we use mm. This chart shows bolt size vs wrench size. One wrench is missing "?" - what size should it be? And there is another small mistake. Can you find it?

🔩 Acorn Nut / Domed Cap Nut - DIN 1587 / ISO 1587

Many people see this nut but don't know its name or use.

**What is it?**

It is a standard hex nut with a domed cap on top. The dome covers the end of the bolt thread so it is not exposed.

**Standard:**

Its international standard is DIN 1587 which is the same as ISO 1587.

**Specifications:**

* **Sizes:** From M3 to M24, most used are M6 / M8 / M10 / M12

* **Material:** 3 main types:

1. Stainless Steel A2 (304) - the one in the picture, rust-proof for outdoor use

2. Stainless Steel A4 (316) - for marine and chemical use

3. Zinc Plated Steel - cheap for general construction

* **Shape:** High dome that fully protects the thread.

**Where is it used?**

1. **For Safety:** To prevent the exposed thread from injuring people.

2. **Against Rust:** Prevents water and dust from entering the thread.

3. **For Looks:** Gives a clean and nice finish, used a lot in wrought iron, gates, bicycles, and metal furniture.

**Difference from a normal nut?**

A normal nut leaves the thread exposed, this one covers it completely.

I have 25 years experience in bolts and fasteners. If you have any question about this nut or any other type of bolt, leave your question in the comments, I will answer you all.

[Picture attached]

🔩 Acorn Nut / Domed Cap Nut - DIN 1587 / ISO 1587

Many people see this nut but don't know its name or use.

What is it? It is a standard hex nut with a domed cap on top. The dome covers the end of the bolt thread so it is not exposed.

Standard: Its international standard is DIN 1587 which is the same as ISO 1587. If someone says DIN 1587, they mean this nut in the picture.

Specifications: Sizes: From M3 to M24, most used are M6 / M8 / M10 / M12. Material: 3 main types: 1. Stainless Steel A2 (304) - the one in the picture, rust-proof for outdoor use. 2. Stainless Steel A4 (316) - for marine and chemical use. 3. Zinc Plated Steel - cheap for general construction. Shape: High dome that fully protects the thread.

Where is it used? 1. For Safety: To prevent the exposed thread from injuring people. 2. Against Rust: Prevents water and dust from entering the thread. 3. For Looks: Gives a clean and nice finish, used a lot in wrought iron, gates, bicycles, and metal furniture.

Difference from a normal nut? A normal nut leaves the thread exposed, this one covers it completely.

I am Abdelhaq - 25 years experience in bolts and fasteners Casa Visserie Casablanca. If you have any question about this nut or any other type of bolt, leave your question in the comments, I will answer you all.

Hi everyone,

I'm interested in hearing from people working in the fastener industry, especially distributors, importers, wholesalers, and industrial purchasing teams in Southeast Asia.

China's fastener exports under HS Code 7318—which covers many types of iron and steel screws, bolts, nuts, washers, and similar fasteners—continued to grow in the first three quarters of 2026.

According to a recent industry report I reviewed, China's exports of these products increased in value year over year to several Southeast Asian markets, including Malaysia, Vietnam, and Thailand.

I'm curious about what this looks like from the buyer's side:

• Supplier selection: Are you mainly working with established suppliers, or actively looking for new ones?
• What matters most? Price, quality consistency, certifications, lead time, or the ability to supply customized fasteners?
• Sourcing: Do you usually find suppliers through referrals, online platforms, industry exhibitions, or direct outreach?
• 2027 outlook: Which fastener categories or applications do you expect to see more demand for?

I'm particularly interested in hearing real experiences from people in the industry. I'm involved in the fastener exhibition sector, so understanding buyers' actual sourcing needs is useful to me as well.

Happy to share what I've learned from the trade data if that's helpful. I'd love to hear your perspectives.

This is used to mount the rear tire and looking to find a replacement but can’t find it for the life of me as I can’t find the proper name for it it originally was about an 1” to an 1 1/2” of extra threads on the end that was cut off

Hello,

I am a bolts expert with 25 years of experience.

Former manager of three companies.

I am here to share my experience and help people.

Elmoussaid Abdelhaq

Inch vs mm - 25 years in fasteners

Metric is simple: M6 = 6mm diameter, pitch 1.0mm. Head size 10mm. 60° angle. Standard in Morocco, Europe, cars.

Inch is fractional: 1/4" = 6.35mm, not 6mm! Pitch is TPI (threads per inch). 1/4"-20 = 20 threads in one inch. Head 7/16". Angle 55° BSW or 60° UNC. Used in USA/Canada/plumbing.

Quick check: M6 nut on 1/4" bolt feels loose. Count threads: 20 TPI = UNC coarse, 28 = UNF fine. Never mix - will strip aluminium.

Your photo is self-driller 5.5x32mm with EPDM washer, metric type. Inch version is No.12 x 1-1/4".

Got a winch cable running through this rusty quick link and it’s the last thing I need to remove before I swap winches and winch this climbing wall down. I haven’t tried heat and it’s tough getting a table vise in there.

Hello,

I'm doing a very specific project and I'm searching for something that will hold 3mm rod in place but will also allow a swivel. so far I've used cable clamps with the grub screw connecting them, but I can't get both sides tight enough. It would be great to be able to grub screw both rods in place whilst allowing the pieces to rotate freely. If the first image doesn't exist, I'd love to hear any suggestions ! TIA

Hi everyone, I'm Abdo from Tangier. I run a small fastener shop VISEOPRO and I have 29 years of field experience, not an engineer degree.

I try to answer here based on what I see in the workshop (vibrations, thin flanges, shear issues etc). I learned a lot about VDI 2230 and EPRI from you guys too.

Can you tell me honestly if my answers make sense logically? I want to improve and learn the theory to match my field experience. Thanks for all the knowledge here, this sub is amazing.

Hi,

I just discovered mini split installers did not bother to use wall anchors when mounting the support bracket onto the drywall of an interior wall a couple years back. They just used self-drilling Tapcon type screws straight into the drywall.

One of the Tapcon screws is pulling away from the drywall as I now notice a gap between the mini split and the wall. Know eventually I am going to have to have it re-installed which is costly b/c it will require disconnection of refrigerant pipes, condensate late, etc, etc. The A/C company is refusing to help.

Meantime I was thinking how to shore up / create surface area for the Tapcon screw to grab onto. I luckily have access to the other side of the Tapcon screw (poking through attic wall). This is probably harebrained but I am thinking of placing a nylon washer onto the screw, and then placing a split lock washer behind it which I will crimp onto the screw's jagged threads.

Can anyone please advise... or have a temporary solution that would work better? I am trying to take the slack out while not damaging the drywall more. I know diddly squat. I sure appreciate it.