MS Screws for Machine or Mild Steel Use | Hebei Wotu Fastener Manufacturing Co., Ltd.
MS screws are usually specified either as machine screws for tapped holes and nuts, or as mild steel screws where the material is the key requirement. That distinction changes the thread form, mating part, finish, strength expectation and inspection method.
For a purchase inquiry, the main decision is not only diameter and length. The screw must match the assembly: metal-to-metal fastening, sheet metal fixing, furniture hardware, light fabrication or general maintenance use.
Brand: Wotu Surface: blue and white zinc plated Specifications: Chinese national standard 6#/8#/10#/12#/16#/20#, rod length 35mm~250mm full range of specifications in stock, supports nonstandard length customization Packaging: 25kg cartons, full pallets packed on wooden pallets, support neutral packaging, private-label customization
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Brand: Hengzuan Surface: color zinc plated, can be customizedblue-white zinc plated Specifications: in stock 4.8/5.5 common wire diameter, rod length 16~125mm full range of specifications, supports nonstandard customized Packaging: 25kg cartons, whole wooden pallets, support neutral packaging, private-label customization
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Brand: Hengzuan Surface: blue and white zinc plated, color zinc plated can be customized on request Specifications: in stock 4.2/4.8/5.5/6.3mm mainstream wire diameter, length 20mm~165mm full range of specifications, nonstandard rod length, drill point size can be customized Packaging: 25kg export cartons, full pallets wrapped with film, supports neutral export packaging, customer private-label customization
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Brand: Wotu Surface: blue and white zinc plated, customized color zinc plated, Dacromet anti-corrosion coating available Specifications: ST5.5, ST6.3 mainstream specifications, rod length 20mm~125mm, full size range in stock, support nonstandard customization, drilling to adapt to steel sheet 2-6mm Packaging: 25kg cartons, whole wooden pallets
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Brand: Hengzuan Surface: blue and white zinc plated, can be customized color zinc plated, black oxide plated Specifications: Comply with GB/T15856.2 Chinese national standard, in stock ST3.5/ST4.2/ST4.8/ST5.5 mainstream wire diameter, rod length 13mm~50mm full range of specifications, nonstandard length customization on demand, drilling applicable plate thickness 2~5mm Packaging: 25kg export cartons, full pallets wrapped with film, supports neutral export packaging, private-label customization
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Brand: Hengzuan Surface: blue and white zinc plated Specifications: in stock ST4.2/ST4.8full range of specifications, length 13~50mm in stock, support nonstandard length customization Packaging: 25kg cartons, solid wood packaging, support neutral packaging, private-label customization
Read MoreSelection criteria
Useful MS screw selection compares the thread type, head geometry, drive recess, material, surface finish and mating component. The right choice depends on whether the screw is fastening into a pre-tapped hole, a nut, sheet metal, timber-based board or another prepared substrate.
| Criterion | What To Check | Why It Matters | Buyer Tip |
|---|---|---|---|
| Meaning of “MS” in the order | Confirm whether the drawing means mild steel screws, machine screws, or a project-specific abbreviation. | The same wording can lead to a different thread type, material, and inspection requirement. | Ask: “Does MS refer to mild steel material or machine screw thread in this item?” |
| Thread type and mating part | Match the screw to a tapped hole, nut, insert, or sheet material before choosing the thread. | Machine threads need a matching internal thread; self-tapping styles form or cut their own thread. | Ask for the mating part material and whether the hole is already tapped. |
| Head style and drive | Compare pan, countersunk, cheese, or hex head styles with the required screwdriver or assembly tool. | Head shape affects seating, appearance, clearance, and torque transfer during installation. | Ask: “Should the head sit flush, stand proud, or fit inside a recessed area?” |
| Material and surface finish | Specify the base material and finish instead of only saying MS screws. | Mild steel without a suitable finish may not suit damp, outdoor, or corrosive locations. | Ask what environment the screw will face and whether a plated, coated, or alternative material is required. |
| Length, diameter, and engagement | Check the clamped material thickness and required thread engagement in the receiving part. | A screw that is too short may strip or loosen; one that is too long can bottom out or protrude. | Ask for the assembly stack thickness, hole depth, and any maximum protrusion limit. |
The first point to confirm is what “MS” means in your drawing or purchase note. If it means machine screw, the buyer should define the thread standard, head style, drive type and whether the screw mates with a tapped hole, nut or insert. If it means mild steel screw, the buyer should still define the screw type, because mild steel can be used across different fastener forms.
This matters because a machine screw will not perform like a self-tapping screw in an untapped hole, and a mild steel screw without the right surface treatment may not suit damp, outdoor or corrosive service. A clear specification prevents substitutions that look similar but assemble differently.
Start with the joint, not the screw name. For a tapped metal part, confirm thread size, pitch, length under the head, head form and drive recess. For thin sheet, plastic, timber or fiberboard, check whether a self-tapping, self-drilling or wood/fiberboard screw is actually the better fit.
Head style affects both assembly and appearance. Pan, cheese and round heads leave a raised bearing surface; countersunk heads sit flush but need a matching countersink. A wrong head choice can cause poor seating, surface damage or uneven clamp load even when the thread size is correct.
Material and coating should follow the service environment. Mild steel can be economical for many indoor assemblies, but the finish still matters for storage, handling and corrosion resistance. If the part will be exposed to moisture, chemicals or outdoor weather, ask what coating options are suitable instead of assuming a plain MS screw is enough.
Avoid sending only a short description such as “MS screw 6 mm.” A useful next step is to share the drawing or sample photo, thread size, length, head and drive type, required finish, mating material and application. If the screw replaces an existing part, include the failed sample or describe the assembly problem.
| Criteria | Importance | Description | Example Options |
|---|---|---|---|
| Meaning of MS | Critical to confirm before selection | MS may refer to a machine screw or to mild steel material. The correct interpretation changes the thread requirement, mating component and acceptable alternatives. | A note saying “MS M5 pan head” may need confirmation on whether M5 machine thread is required, mild steel material is required, or both. |
| Thread and mating part | Determines whether the screw will assemble at all | Machine screws require a compatible internal thread, such as a nut, tapped hole or insert. Self-tapping and self-drilling screws are chosen for different hole conditions and should not be substituted without checking the joint. | A tapped bracket may need a machine screw, while thin sheet without a tapped hole may call for a self-tapping screw instead. |
| Head style and seating | Affects clamp, appearance and surface damage | Raised heads provide a bearing surface above the part, while countersunk heads need a matching countersink to sit flush. A wrong head form can make the joint look fitted while leaving poor seating. | A countersunk screw used on a flat, non-countersunk plate may contact only at the edge instead of seating properly. |
| Material and surface finish | Important for service environment and storage conditions | Mild steel screws may need an appropriate coating for handling, storage and corrosion resistance. The finish should be selected according to indoor use, moisture exposure, appearance and compatibility with the assembled parts. | An indoor equipment cover and an outdoor bracket may require different finish choices even if the screw dimensions are the same. |
| Length definition | Prevents ordering errors and assembly interference | Screw length can be interpreted differently depending on head style. Buyers should confirm whether length is measured under the head or as overall length for the selected screw form. | A countersunk screw is commonly treated differently from a pan head screw when comparing usable length in the joint. |
Related Options
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It can mean either, depending on the drawing, buyer note or local purchasing habit. Confirm the intended meaning before ordering, because a machine screw describes the thread and mating method, while mild steel describes the material.
Not normally. A machine screw is designed to engage with a tapped hole, nut or threaded insert; it does not create its own thread like a self-tapping screw. If the hole is plain sheet metal, plastic or timber-based board, a different screw type may be needed.
Mild steel is often chosen for general indoor fastening where cost and availability matter, but it usually depends on a suitable finish for corrosion protection. Stainless steel is commonly considered where moisture or corrosion resistance is more important, though it may not be the same choice for every load, thread or budget requirement.
Small differences in thread pitch, diameter, head angle, recess type or length measured under the head can stop a screw from seating correctly. A replacement should match the mating thread and head geometry, not just the visible overall length.
Send the screw size, thread pitch if known, length, head style, drive type, material or finish requirement, mating part and application. A drawing, sample photo or old screw sample helps clarify details that are easy to describe incorrectly.
Share what MS means in your specification, the screw size and length, and the assembly material or mating part. A drawing, sample photo, head style, drive type and required finish will help confirm the correct fastener.
