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300-Piece M3 Screw Kit ISO 7380, A2-70 Stainless Steel, 8 - 18 mm, with Nuts and Washers
A practical set for assembly and repair work in electronics, fine mechanics or DIY projects, including 300 stainless steel M3 screws resistant to corrosion and wear, suitable for precise and secure fastening, with an M3 thread for wide compatibility, supplied in a compartmentalized box for quick organization and easy access.
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The set of 300 M3 fasteners made of A2-70 stainless steel combines low button head hex socket screws (ISO 7380 standard), nuts, flat washers and spring washers, all kept in a transparent box with compartments. It is suitable for fixing electronic boards to spacers, mounting modules in enclosures, assembling 3D printers, panels, brackets and other small mechanical constructions.
The screws have an M3 metric thread with a 0.5 mm pitch and are offered in six lengths: M3 x 8, M3 x 10, M3 x 12, M3 x 14, M3 x 16 and M3 x 18, 25 pieces of each. The low button head has a diameter of 5.7 mm and a height of 1.65 mm, and the hex socket is tightened with a 2 mm Allen key. The A2-70 stainless material resists moisture and corrosion well.
The main features include the box with 9 compartments and the label on the lid indicating the contents of each one, 50 M3 nuts, 50 flat washers and 50 spring washers, which complete the 150 screws. Each length has its own compartment, so the parts are easy to select and remain sorted.
Specifications:
Type: M3 screw, nut and washer set
Total quantity: 300 pieces
Screw standard: ISO 7380
Material: A2-70 stainless steel
Thread: M3, 0.5 mm pitch
Head shape: Low button head, with hex socket
Head diameter: 5.7 mm
Head height: 1.65 mm
Tightening key: 2 mm Allen key
Screw lengths: M3 x 8, M3 x 10, M3 x 12, M3 x 14, M3 x 16, M3 x 18
Screws: 25 pcs. of each length (150 pcs.)
M3 nuts: 50 pcs.
Flat washers: 50 pcs.
Spring washers: 50 pcs.
Packaging: Transparent plastic box with 9 compartments
Layout:
| Element | Function |
|---|---|
| Compartment M3 x 8 | 25 screws with a length of 8 mm. |
| Compartment M3 x 10 | 25 screws with a length of 10 mm. |
| Compartment M3 x 12 | 25 screws with a length of 12 mm. |
| Compartment M3 x 14 | 25 screws with a length of 14 mm. |
| Compartment M3 x 16 | 25 screws with a length of 16 mm. |
| Compartment M3 x 18 | 25 screws with a length of 18 mm. |
| Compartment M3 Nuts | 50 M3 nuts. |
| Compartment Washer | 50 flat washers, which distribute the pressure and protect the surface of the part. |
| Compartment Spring washer | 50 spring washers, which help maintain the tightening when the part vibrates. |
| Label on the lid | Indicates the A2-70 ISO7380 marking, the total quantity of 300 pieces and the contents of each compartment. |
Usage:
Choose the screw length according to the thickness of the parts to be joined. The length must be greater than the thickness of the parts, plus the thickness of the washers and the nut, plus at least 1 mm of free thread protruding beyond the nut.
Measure the actual thicknesses with a caliper and do not estimate them by eye. The length of a round head screw is measured from under the head to the tip, so the head is not included in the calculation.
Pass the screw through the holes of the parts, then fit onto the threaded end a flat washer, a spring washer and a nut, in this order. The spring washer is placed between the flat washer and the nut.
Screw the nut by hand until it makes contact, then tighten the screw with a 2 mm Allen key, fully inserted into the socket. For several screws on the same part, tighten them in a crosswise pattern, a little at a time.
Screw in slowly and with a hand key, not with an electric screwdriver, because stainless steel can seize at high rotation speed. A drop of oil on the thread reduces the risk.
On printed circuit boards, stop at the first clear resistance so as not to deform the laminate. Do not force a jammed screw, instead remove it and check the thread.
After use, return the unused parts to their compartment so that the lengths are not mixed up.
- Material
- Stainless steel A2-70
- Type
- Set of M3 screws, nuts and washers
- Length
- M3 x 8, M3 x 10, M3 x 12, M3 x 14, M3 x 16, M3 x 18
- Quantity
- 300 bucati
- Thread
- M3, pas 0.5 mm
- Shape
- Low round head with hex socket
Produs destinat utilizarii in proiecte electronice, automatizari, prototipare, educatie si cercetare.
Produsul trebuie utilizat numai conform specificatiilor tehnice mentionate in descriere si/sau in documentatia produsului.
Avertismente generale de siguranta:
Nu utilizati produsul la tensiuni, curenti sau temperaturi peste valorile specificate.
Montajul si conectarea trebuie realizate de persoane cu cunostinte tehnice minime in domeniul electric/electronic.
Evitati scurtcircuitele, inversarea polaritatii si conectarea gresita a alimentarii.
Nu lasati produsul alimentat nesupravegheat in timpul testelor.
Produsul nu este jucarie si nu este destinat copiilor.
Pentru modulele electronice, se recomanda utilizarea in carcase, panouri sau montaje protejate, dupa caz.
Identificare produs:
Denumirea produsului, codul/SKU-ul si caracteristicile tehnice sunt mentionate in pagina produsului si/sau pe eticheta ambalajului.
Producator / Importator / Distribuitor:
Sigmanortec S.R.L.
Calea Bucuresti nr. 9, Targu Jiu, Gorj, Romania
E-mail: [email protected]
Website: www.sigmanortec.ro
Persoana responsabila in UE:
Sigmanortec S.R.L.
Calea Bucuresti nr. 9, Targu Jiu, Gorj, Romania
E-mail: [email protected]
Documentatie si siguranta:
Pentru informatii suplimentare, fise tehnice, declaratii de conformitate sau instructiuni, ne puteti contacta la [email protected].
Reviews (1) - Review moderation
Am primit coletul foarte repede,ambalat corespunzător iar la deschide am avut surpriza să găsesc și o bombonică gumată lângă cutia cu șuruburi !!! Mulțumesc Sigmanortec !!! Cu siguranță voi mai cumpăra de la voi !!! ❤️❤️❤️
This tutorial covers the kit itself, because it is a set of mechanical fasteners and needs no power supply or program. The 300 A2-70 stainless steel pieces include M3 screws in six lengths, nuts, flat washers and spring washers, and they are used to fix electronic boards to spacers, to mount modules in enclosures, for 3D printers, panels and project brackets.
The screws have a low round head and an internal hex socket (ISO 7380), so they are tightened with a 2 mm Allen key. The box has 9 compartments, and the label on the lid shows what each one contains.
How it works:
An M3 screw has a metric thread with an outer diameter of 3 mm and a pitch of 0.5 mm. When you tighten the screw into a nut or a threaded hole, turning the key converts into a clamping force between the parts. The length of a round head screw is measured from under the head to the tip, so the head is not added to the calculation.
The right length is chosen with a simple sum: the thickness of the parts being joined, plus the thickness of the washers, plus the thickness of the nut, plus at least 1 mm of thread protruding beyond the nut. At a pitch of 0.5 mm, 1 mm means two full turns of thread.
Example with assumed values: a 1.6 mm board, a 3 mm panel, a 0.5 mm flat washer, a 0.8 mm spring washer and a 2.4 mm nut add up to 8.3 mm. Add 1 mm of free thread to get 9.3 mm, so choose an M3 x 10 screw. Measure the actual thicknesses with a caliper.
The flat washer spreads the force over a larger area and protects the board or plastic. The spring washer goes between the flat washer and the nut and helps maintain the tightening when the part vibrates.
Connection:
The product has no electrical connections and needs no power supply. The table shows how the kit parts are assembled, instead of a wiring connection.
| Product pin | Connects to | Role |
|---|---|---|
| M3 x 8, M3 x 10, M3 x 12, M3 x 14, M3 x 16, M3 x 18 screws (25 pcs each) | M3 nut or M3 threaded hole | Holds the parts together, and the length is chosen based on the thickness of the parts. |
| M3 nut (50 pcs) | Threaded end of the screw | Locks the joint when there is no threaded hole. |
| Flat washer (50 pcs) | Between the part and the nut or between the part and the screw head | Spreads the pressure and protects the surface. |
| Spring washer (50 pcs) | Between the flat washer and the nut | Reduces loosening of the tightening due to vibration. |
Setup:
The kit has no buttons, jumpers or adjustments. Preparation consists of choosing the length and the tools. For the screws you need a 2 mm Allen key, and for the nuts a suitable open-ended or socket wrench, checked by test-fitting it on one of the nuts in the kit.
| Compartment | Contents | Typical use |
|---|---|---|
| M3 x 8 | 25 screws | Fixing into threaded holes or on short spacers |
| M3 x 10 | 25 screws | Boards on spacers or thin panels |
| M3 x 12 | 25 screws | Board, spacer and nut |
| M3 x 14 | 25 screws | Thicker layers or overlapping parts |
| M3 x 16 | 25 screws | Enclosures and brackets with thick walls |
| M3 x 18 | 25 screws | Thick assemblies or long spacers |
| M3 Nuts | 50 nuts | Counter-nut for all lengths |
| Washer | 50 flat washers | Under the nut or under the screw head |
| Spring washer | 50 spring washers | Between the flat washer and the nut |
Step 1: measure the total thickness of the parts to be joined with a caliper.
Step 2: add the thicknesses of the washers and the nut you use.
Step 3: add 1 mm for the free thread and choose the closest length in the kit that is greater than or equal to the result.
Step 4: close the compartment after use so that the lengths do not get mixed up.
Usage example:
Example: fixing a 1.6 mm printed circuit board to a 3 mm panel with four screws and nuts. Choose M3 x 10 screws, calculated as in the How it works section. Pass each screw through the hole in the board, then through the panel, from top to bottom.
On the panel side, fit in order a flat washer, a spring washer and a nut. Screw the nut on by hand until it bears against the panel, then gently tighten all four screws in a cross pattern, a little at a time. Tightening in a cross pattern prevents the board from tilting.
After the final tightening the spring washer is flattened, and the end of the screw extends past the nut by at least two turns of thread. The board must not move when you gently push it with a finger, and the board laminate must not be deformed around the holes. Stop at the first clear resistance when tightening a printed circuit board.
Common problems:
The Allen key slips in the socket. The cause is usually a worn key or one of the wrong size, and the socket can become rounded. Use the 2 mm key, press it fully into the socket and replace the screw if the socket is already deformed.
The screw does not reach to grip the nut. The cause is a length that is too short for the thickness of the parts and washers. Move up to the next length in the kit, or remove the spring washer if the space is very limited.
The screw seizes in the nut or threaded hole before the final tightening. Stainless steel tends to gall when the threads rub together at high rotation speed. Screw in slowly with a hand key, and put a drop of oil on the thread. Do not force a seized screw, instead remove it and check the thread.
The screw does not go into the hole of a 3D printed part or a module. The hole may be too small or may have a different thread. Check the hole diameter, clean out any plastic debris and do not force the screw into unthreaded holes in hard material.
The joint loosens over time. On parts that vibrate, the tightening drops if the spring washer is missing or if the nut was not tightened fully. Add the spring washer and tighten again at the end of the assembly.
Limitations and tips:
The kit covers only M3 thread with a 0.5 mm pitch, so it does not fit holes with another diameter or thread. The low round head has a small height, which makes it suitable for narrow spaces, but the 2 mm hex socket can round out if you tighten too hard.
Keep the 2 mm Allen key next to the box and sort the parts by compartment. With this set you can assemble enclosures, module brackets, 3D printer frames and project panels without buying separate parts for each length.
