TX28 6-Lobe Pin TX Security Grub Screw — Cup Point
Cup point 6-lobe pin security grub screw, M3–M24 as tabulated: min socket depth t 0.8–6.8 mm, socket width s 1.75–13.45 mm, tools TX6–TX60. Steel, A2 and A4 stainless steel as standard. Availability matrix tabulated 4–120 mm (imperial 3/8″–1 1/2″) but its markers are not defined by the collected legend — all sizes route to quotation.
Last updated: 2026-11
Specifications
The cup point is the default grub screw, and TX28 is its pin-secured version: a headless set screw, fully threaded, whose concave cup end bites slightly into the mating surface to hold a collar, pulley or knob against rotation while staying flush inside the bore. The centre pin in the 6-lobe socket keeps standard Torx tools out, and the collected page emphasises the drive’s resistance to cam-out — relevant here because grub screws are routinely tightened hard enough to shear the recess out of lesser drives. The tabulated range is the widest in this batch: M3 through M24, with stated minimum socket depths from 0.8 mm to 6.8 mm and socket widths from 1.75 mm to 13.45 mm, driven by TX6 to TX60 tools. An imperial table lists No.6-32 UNC through 3/8-16 with lengths from 3/8″ to 1 1/2″, but its socket-width row is all dashes, so no imperial drive-size claim is made. One fail-closed note governs availability: the page’s legend defines only a to-order marker, and that marker appears on none of the matrix cells — the cells carry an icon the collected legend never defines, so no per-pair stock claim can be made and every size pair routes to quotation. Supply is stated in steel, A2 and A4 stainless steel as standard.
| Designation | TX28 — cup point security grub screw (set screw), 6-lobe pin TX drive, headless, fully threaded; cup end cuts into the base surface to resist rotation; reusable two-way, medium security |
|---|---|
| Thread range (tabulated) | M3, M4, M5, M6, M8, M10, M12, M16, M20, M24 |
| Min socket depth t (mm) | M3 0.8 · M4 1 · M5 1.3 · M6 1.6 · M8 2.7 · M10 2.9 · M12 3.2 · M16 4.3 · M20 5.3 · M24 6.8 |
| Socket width s (mm) | M3 1.75 · M4 2.4 · M5 2.8 · M6 3.35 · M8 4.5 · M10 5.6 · M12 6.75 · M16 8.95 · M20 11.35 · M24 13.45 |
| Tool size (collected) | TX6 (M3) · TX8 (M4) · TX10 (M5) · TX15 (M6) · TX25 (M8) · TX30 (M10) · TX40 (M12) · TX50 (M16) · TX55 (M20) · TX60 (M24) |
| Length axis (tabulated, unclaimed) | metric matrix tabulates 4–120 mm across M3–M24; imperial matrix 3/8″–1 1/2″ across No.6-32 UNC–3/8-16. Collected legend defines only a to-order marker that appears on no cell — the cell markers are not defined by the legend, so no per-pair availability is claimed; confirm every pair at quotation |
| Security principle | Reusable two-way fixing; pin-in-recess resists standard Torx bits; no cam-out at high torque per the collected page |
| Standard materials | Steel, A2 stainless steel, A4 stainless steel; other materials and finishes on request |
Materials
- Steel (standard)
- A2 stainless steel (standard)
- A4 stainless steel (standard)
- Other materials and finishes on request
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (TX28 6-Lobe Pin TX Security Grub Screw — Cup Point) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Why are the lengths on this page not marked available or to order?
The published availability matrix carries a legend that explains only one marker — a to-order symbol — and that symbol appears on no cell; every cell uses an icon the legend never defines. Rendering those cells as available would be an assumption, so this page reports the tabulated size axis honestly and routes every thread-and-length pair to quotation. In practice this is an order-confirm step, not an obstacle: the full M3–M24 range with lengths to 120 mm is stated as standard supply.
When does cup point beat flat or cone point?
Cup point is the general-purpose default: its hollowed end digs slightly into the shaft or housing, giving the highest resistance to rotation of the non-penetrating points, at the cost of a small mar on the mating surface. Flat point (TX32) is for soft materials and ground flats where surface damage matters; cone point (TX34) is for permanent set screws that are meant to penetrate; dog point (TX33) locates in a matching hole so the collar can rotate during adjustment. If your part gets repositioned often, cup point on a rotating shaft is the wrong trade — use dog point.
What should an RFQ for TX28 state?
State the designation (TX28 6-lobe pin TX cup point grub screw), thread size and length, material (steel, A2 or A4 stainless as standard), the mating surface it bites into, quantity per size, and your bit inventory (TX6–TX60 per size). Because availability is confirmed at quotation for this line, ask the supplier to mark stock status per pair on the quote rather than assuming the tabulated axis implies shelf stock.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support