TIGERFASTENERS
Machine Screws
A machine screw's thread is formed beforehand, and so is the mating internal thread — a tapped hole or a nut. Nominal diameter and pitch have to match exactly for it to engage at all, which is the fundamental difference from the self-tapping family.
Specification options
| Volume range | M1.0 – M5.0 |
|---|---|
| Maximum size | M16 |
| Standards | DIN 84 · DIN 963 · DIN 965 · DIN 7985 · ISO 1207 · ISO 2009 · ISO 7045 · ISO 7046 · JIS B 1101 · JIS B 1111 |
| Materials | see Materials |
| Finishes | see Finishes |
| Minimum order | From 10,000 pcs, depending on the part |
Head styles
For countersunk and oval heads the style is only half of it: the included angle has to be paired with the hole — 82° and 90° belong to two different systems, and a mismatch will not sit flat.
Drive types
Choosing the thread
-
Coarse
The default. Larger pitch, more tolerant of hole condition, less prone to stripping over repeated assembly.
-
Fine
Greater effective section at the same outside diameter and marginally better self-locking; suits thin walls or fine preload adjustment. The trade-off is sensitivity to hole accuracy and easier stripping.
Where it most often goes wrong
Each of these causes scrapped lots or rework on the floor. None of them is theoretical.
Mixing metric and imperial. M3 and #4-40 look alike. Forcing one into the other destroys both threads, and it is invisible at goods-in — you find out halfway down the hole.
Phillips driven with a Pozidriv bit, or the reverse. The crosses look identical; Pozidriv has four additional fine ribs in the recess. The wrong bit cams out, and on an automated line that becomes a whole lot of rejects.
Pitch not specified. M3×0.5 and M3×0.35 share an outside diameter. A purchase order that says only “M3” has not specified the part.
How length is measured
One rule covers it: if the head sinks into the work, measure overall; if it stays on the surface, measure under the head.
| Head style | Datum | Why |
|---|---|---|
| Countersunk (flat) | Overall length | The head sits flush in the countersink, so it counts |
| Oval (raised countersunk) | Overall to the head diameter | The cone sinks, the dome stays proud; measure to where they meet |
| Pan / round | Under head | The head stays entirely on the surface |
| Button | Under head | Same |
| Hex / hex washer | Under head | Same |
| Socket head cap | Under head | Same |
Full explanation → Where the standards stop at this size → Tolerance stack-up and the screw →
Worth reading before you specify this type
One question per page, with the standard it rests on and the range that standard is valid over.
- Reading a screw specification: what M2×0.4×6 leaves out — The type most often mis-ordered on an incomplete designation — tolerance class, length datum, unstated fine pitch
- Thread engagement: make the screw fail, not the hole — The female thread already exists, so engagement is set by the hole or nut rather than by the screw
- Right torque, wrong clamp force — Driving into an existing metal thread is where looked-up nut factors get misapplied most often
If your part sits below M6, the micro screw page collects the four constraints that only appear at these sizes.
Enquiries
Machine Screws come in a lot of combinations. Tell us the item, size, material, finish, annual usage and application, and we will come back on feasibility and lead time. A drawing or a sample is fastest — quoting against the real part saves a great deal of guessing.
Volume range M1.0 – M5.0, standard fasteners up to M16. Minimum order From 10,000 pcs, depending on the part.