DIN 404 Slotted Capstan Screws
DIN 404 capstan screws with slotted cylindrical head and cross-hole for a tommy bar, M2 to M10 — the head you can wrench by hand through a transverse rod — with the full collected 8-size table: cross-hole diameter, head geometry, slot and thread lengths.
Last updated: 2026-11
Specifications
DIN 404 is the capstan screw: a slotted cylindrical head screwed that carries a cross-drilled hole through the head so a rod — the tommy bar — can be slipped through and used as a wrench lever for hand adjustment. That combination of a slot for a screwdriver and a through-hole for a bar makes it the classic fastener for machine guards, clamping handles and tooling that is set by hand and re-set often. The collected table runs M2 to M10 and tabulates the whole head system: the cross-hole d 1 with its nominal and maximum limits (the dimension that decides which tommy-bar stock fits), head diameter d k and height k with their limit bands, the slot width n and depth t limits, the washer-face style shank d s limits, the thread length ladder b printed in the standard's "+2P, 0" notation (basic length plus two pitches, permissible minus zero), and the pitch P per size. Where a knurled thumb screw (DIN 464) is too fine a grip and a plain hex is too tool-dependent, the capstan head is the middle answer. Materials, property classes and finishes are not printed by the collected specification and follow the drawing callout.
| Standard | DIN 404 — slotted capstan screws (cylindrical head with tommy-bar cross-hole) |
|---|---|
| Series | M2 – M10 (8 sizes tabulated) |
| Tabulated geometry | Per size: pitch P, thread length b (noted +2P,0 — plus two pitches, minus zero), cross-hole d 1 (min=max nominal / max), head diameter d k (max=nominal / min), shank d s (max=nominal / min), head height k (Nominal / max / min), slot width n (Nominal / max / min), slot depth t (min / max) |
| Dimensions at M3 | Cross-hole d 1 nominal 1.5 (max 1.64); head d k max 5.5 / min 5.38; d s max 3 / min 2.86; k nominal 4; slot n nominal 0.8; t min 1 / max 1.25; thread length b 19 |
| Dimensions at M6 | Cross-hole d 1 nominal 3 (max 3.14); head d k max 10 / min 9.85; d s max 6 / min 5.82; k nominal 8; slot n nominal 1.6; t min 2.2 / max 2.6; thread length b 28 |
| Head / drive form | Cylindrical head with transverse through-hole d 1 for a tommy bar, plus slotted drive |
| Materials / strength | Not tabulated by the collected specification — per RFQ (property class and finish per drawing callout) |
Materials
- Material, property class and finish specified per RFQ — the collected specification table covers geometry only
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 (DIN 404 Slotted Capstan Screws) 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
When is a capstan head the right choice over a knurled thumb screw?
The two solve the same problem — hand-tightening without tools — at different torque levels. A knurled thumb screw is gripped by fingers alone, which caps the torque you can apply; the capstan head lets you push a tommy bar through the cross-hole d 1 and multiply your grip into a real clamping force, while the slot still accepts a screwdriver for final tightening or for assemblies where the bar is stowed. That is why capstan screws persist on machine guards, adjustable stops and fixture clamps that are set firmly by hand and re-set often. Check the d 1 column against your bar stock: it is tabulated with a nominal and a maximum limit because the hole is drilled, and a bar that fits the minimum may bind at the maximum tolerance.
What does the "+2P, 0" thread length notation mean?
It is how the collected table headers its b column: the thread length is stated as the basic length plus two thread pitches (2P), with a minus-zero tolerance — the tabulated figure is the minimum that must be reached. For M6 the table prints b = 28. Because the notation ties the figure to the pitch of each size, the practical move when a drawing calls an unlisted length is to state the length explicitly at quotation rather than extrapolating the ladder yourself; we confirm the resulting thread length against the standard before production.
What is the MOQ and lead time for these screws?
Minimum order quantity is 10,000 pieces per item. Stocked sizes ship in 3–7 days; non-stock diameters, lengths or finishes are quoted with a confirmed schedule. Common sizes in this designation are widely stocked — confirm the exact schedule against quantity and size mix at quotation.
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