Engineering Guide · 5 min read
Pan Head Screws: ISO 7045, DIN 7985 and ASME B18.6.3
Identify pan heads, match H/PH and Z/PZ drives, and separate machine screws from tapping screws. Check ISO 7045, ISO 14583, DIN 7985 and inch ASME requirements.
The short answer: a typical recessed pan head has a rounded top, a distinct side wall and a flat bearing surface beneath the head. It sits above the part rather than inside a countersink. ISO 7045 covers metric pan head screws with type H or Z cross recesses; ISO 14583 covers the metric six-lobe socket form. For inch parts, select the specified pan-head product in ASME B18.6.3. Identify the head, drive and thread form together before choosing the standard.[1][2][3]
This article belongs to the Bolt and Screw Head Types Guide. It focuses on identifying and specifying pan heads; “Phillips screw” alone describes neither the complete head nor the thread.
Identify the pan profile before naming the recess
Read the side view first. A typical recessed pan head combines a rounded upper surface with a short side wall and a flat underside. A button head has a low domed profile; a flat countersunk head has a conical bearing surface. A cross recess can appear in several head shapes, so it cannot identify a pan head by itself. Slotted pan-head forms can have a flatter top with rounded edges; check the specified product profile.[3]
The Phillips pan head drawing and inch dimension tables show inch head dimensions. Check the head diameter, head height and recess details in the required product standard.
Use the flat seat when a projecting head is acceptable
A pan head gives a projecting, top-driven head without requiring a conical seat. That arrangement suits a removable instrument cover, an equipment panel or a small bracket when the head can remain above the surface and the driver can reach it. Check clearance above the head and room to keep the driver aligned with the screw axis.
The flat underside still needs enough supported mating surface. On thin sheet or a softer component, assess indentation under the required clamp load and any specified washer. A separate washer's outside diameter and hardness can be selected for the joint; the word “pan” does not settle that choice. See the washer selection guide.
If the finished face must be flush, select a correctly designed countersunk assembly. If a particular low head height matters, compare the actual head limits rather than assuming that every button head is lower than every pan head. The standard and nominal size determine the dimensions being compared.
Choose H/PH, Z/PZ or a six-lobe drive deliberately
ISO 7045 offers type H or type Z cross recesses. ISO 8764-1:2004 pairs form PH driver tips with H recesses and form PZ tips with Z recesses.[1][4] Specify both the recess type and its required size; do not choose the bit solely from the thread diameter.
Phillips and Pozidriv can look similar from above. Pozidriv has a second, narrower cross rotated 45° from the main cross, a useful identification clue. Wiha warns that the wrong driver or bit can damage both tool and screw.[5] Match the specified tip and size before applying the assembly torque.
A six-lobe internal drive, commonly called a Torx-type drive, changes the product reference. ISO 14583:2011 covers the metric hexalobular socket pan head; it is separate from ISO 7045's cross-recess form.[2] A six-lobe recess and an internal hexagon are also different drives, even though both are sometimes called “socket” in a catalog.
Select the product standard, then verify an old DIN callout
| Product to specify | Reference | What the description must retain |
|---|---|---|
| Metric pan head with H or Z cross recess | ISO 7045:2011, product grade A, M1.6–M10.[1] | Pan head, the required H/Z recess and metric thread details. |
| Metric pan head with six-lobe socket | ISO 14583:2011, product grade A, M2–M10.[2] | Hexalobular socket, its size and the specified metric product. |
| Inch pan head machine screw | ASME B18.6.3-2024, within its covered slotted and recessed head product forms.[3] | The pan-head machine-screw form, exact drive, inch thread and edition. |
| Legacy cross-recessed metric head | DIN 7985:1990-08; withdrawn and replaced by DIN EN ISO 7045:1994-10 in the publisher's record.[6] | The original edition or agreed successor, with head and recess dimensions checked. |
Product grade A identifies product accuracy, not a strength class. Material, mechanical properties and finish remain separate requirements. For a DIN replacement, Würth notes changes in some head dimensions, thread lengths and recess penetration depths between DIN 7985 and ISO 7045.[7] Check the drawing's controlled features before accepting combined “DIN / ISO” stock.
Read the thread as carefully as the head
A pan head does not tell you whether the screw needs a prepared mating thread. A machine screw engages the specified internal thread in a nut, insert or tapped component. A tapping screw forms or cuts its mating thread in the specified hole, following a different thread and mating-hole specification. ISO 7049:2011 covers cross-recessed pan head tapping screws, separately from ISO 7045.[8] ASME B18.6.3 also covers several product categories, so its number still needs the actual screw type.[3]
For a replacement, record the thread designation, pitch or TPI and mating-hole detail, rather than matching the head photograph and overall size. Keep nominal screw length separate from thread length; a conventional pan head is measured from beneath the head. The size-callout guide explains the thread designation.
Write the head, drive and mating thread on the RFQ
A useful starting description is pan head machine screw — ISO 7045:2011 — type H cross recess — M4 × 12. Confirm the required recess size from that product and add the remaining requirements:
- Head and standard: pan profile, product standard and edition, diameter/height limits where the assembly controls them.
- Drive: recess type and size, matched driver and access above the head.
- Thread and length: machine or tapping product, diameter, pitch or TPI, fit, under-head length and required engagement.
- Seat and supply: supported flat seat, washer arrangement, material, mechanical properties, finish, quantity and inspection documents.
Complete the order using How to Specify a Bolt; interpret the material and strength designation with Fastener Grades Explained.
References
- ISO. ISO 7045:2011. Public scope for metric pan heads with H/Z cross recesses; confirmed current in 2026.
- ISO. ISO 14583:2011. Public scope for metric hexalobular socket pan heads; confirmed current in 2026.
- ASME. ASME B18.6.3-2024. Inch machine, tapping and metallic drive screw public listing and scope.
- ISO. ISO 8764-1:2004. Driver-tip scope specifying PH/H and PZ/Z pairing.
- Wiha. Screw profiles — Phillips and Pozidriv. Toolmaker's identification and wrong-driver guidance.
- DIN Media. DIN 7985:1990-08. Withdrawn edition and replacement by DIN EN ISO 7045:1994-10.
- Würth. ISO 7045 pan head screws — DIN replacement notice. DIN/ISO head, thread-length and recess-depth changes; manufacturer catalog information, not a universal interchangeability approval.
- ISO. ISO 7049:2011. Separate cross-recessed pan head tapping-screw scope; confirmed current in 2026.