TIGERFASTENERS
Type-Cutting Screws
A slot at the end — or along the flank — forms a genuine cutting edge. Compared with a self-tapping thread it cuts with less resistance and lower driving torque, which suits castings, thicker metal and rigid plastics where an ordinary self-tapper snaps or bursts the hole.
Specification options
| Volume range | M1.0 – M5.0 |
|---|---|
| Maximum size | M16 |
| Standards | DIN 7513 · DIN 7516 · ISO 1478 |
| Materials | see Materials |
| Finishes | see Finishes |
| Minimum order | From 10,000 pcs, depending on the part |
Head styles
Drive types
Choosing the thread
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Type Fmachine screw form with slots
Machine screw thread form, so it interchanges with standard nuts. Use where the part may later be converted to a standard fastener.
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Type D / T
Different slot geometry, different swarf path and cutting resistance. Select on material and hole depth.
Where it most often goes wrong
Each of these causes scrapped lots or rework on the floor. None of them is theoretical.
Repeated assembly. The thread it cut fits that screw. Removed and refitted, the cutting edge cuts again and the hole grows each time. Anywhere that comes apart repeatedly wants a nut or a tapped hole.
Ordering by type letter without saying whose letters. The cutting types are not one group: BF and BT cut but run a spaced thread, while D, F, G and T cut on a machine-screw pitch — different hole, different standard. And the letters collide across systems: ISO uses C and F for cone end and flat end, which are point shapes, where ASME Type C is a machine-screw-pitch thread forming screw and Type F is a cutting one. A metric drawing saying bare "Type C" is genuinely ambiguous. There is also no official table converting ST sizes to type letters — ISO 1478:1999 maps ST to legacy screw numbers and marks it for information only. Which letter means what, and in whose system.
Assuming the cutting types are the obsolete ones. They are not marked as withdrawn. The type ASME actually flags as not recommended for new designs is Type C — a forming type — on grounds of declining usage and generally higher driving torque. Type A is the one the standard suggests superseding with AB, and even that is worded as a preference rather than a replacement.
Blind hole with no chip reservoir. Cutting produces swarf. With nowhere for it to go, the chips jack the screw — torque rises while the part is not seated.
Blunt edges going unnoticed. As the cutting edge dulls, torque rises. An automated line watching only a torque ceiling can read “blunt” as “tight”.
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 →
Enquiries
Type-Cutting 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.
Request a quotation
Tell us the part and the quantity. We will come back on feasibility, lead time and price.
Or email us directly sales@tigerfasteners.com