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+86 13143444311
Email：sst@szsst88.com
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Address：Building 9, First Industrial Zone, Tantou Industrial City, Songgang Street, Baoan District, Shenzhen 518105, Guangdong, China
Type:M3 pan head machine screw (combination drive)
Materials:Carbon Steel
Surface treatment:Nickel Plated
Head Type:Pan Head
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Drive:Combination Phillips and slot
Thread:M3 x 0.5 machine thread, right hand
Forming:Cold heading; thread rolled, then nickel plated
Number:743
We manufacture M3 pan head machine screws in carbon steel with a nickel finish and a combination cross-and-slot drive, part of a family quoted from M1 to M14. Head diameter, recess, thread class and length are taken from your drawing.
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ISO 9001:2015 · Manufacturing since 1998 · 8,678+ customers · 89 countries and regions
Made to order – there is no stock catalogue. Each part is produced to your drawing, and production starts after drawing review and first-article approval.
An M3 pan head machine screw is a metric screw with a 3 mm nominal thread diameter, a low domed head with a flat bearing face, and a machine thread that engages a tapped hole or a nut. The recorded item on this page is the M3 size in carbon steel with a nickel finish and a combination cross-and-slot drive, quoted from M1 to M14 with Number 743.
M3 thread. 3 mm nominal diameter with a 0.5 mm coarse pitch. It is the size that most small equipment settles on: big enough to take a real torque, small enough to fit a compact enclosure.
Pan head. A low dome on a flat bearing face, wider than it is tall. The bearing face spreads the clamp load and the low profile keeps the head clear of whatever sits above it.
Combination drive. A cross with a slot cut through it, so a Phillips bit or a flat blade can turn it. On M3 that is a practical choice: the drive is small, and having two options reduces the chance of a stripped head in service.
Nickel finish. A hard, bright deposit that protects the steel and gives a silver tone close to stainless, which is why it is used on visible small assemblies.
Together these decide the joint: the M3 thread matches the tapped hole, the pan head bears on the panel, the combination drive takes the tool at hand, and the nickel keeps the part bright. That is why an M3 pan head machine screw is specified by thread, head, drive and finish together.
The body of this M3 pan head machine screw is carbon steel wire, with the grade and heat number kept with the batch record. The property class is fixed on the drawing, because on M3 the head-to-shank ratio is tight and the class decides how much torque the head can take before the recess deforms.
The pan head is formed in the heading die with its dome and bearing face, and the head diameter on M3 is about 5.6 mm on the standard form — roughly 1.9 times the thread diameter. That ratio is what gives the bearing face its area without making the head tall.
The combination recess is formed in the same stroke. On a 3 mm thread the recess is small, so its depth is set against the head height: deep enough for the bit to seat, shallow enough that the head does not open up at the corners.
The machine thread is rolled full length. Rolling keeps the grain continuous and gives a smooth flank, and it holds the 0.5 mm pitch consistently along the length, which matters because M3 joints are often short and rely on only a few engaged threads.
The nickel is applied after the thread is rolled. It adds a few microns to the flanks, so the thread is gauged in its plated condition, and the recess is driven with both tools after plating because the film collects in the corners of a small cross.
This page covers the M3 size of the family; the recorded configuration is quoted from M1 to M14 overall, with M3 as the referenced size in carbon steel and nickel. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission, and on M3 the practical length range is set by the joint rather than the machine.
| Item | How it is defined | What we control |
|---|---|---|
| Thread | M3, 0.5 mm coarse pitch | Gauged per batch after plating |
| Head diameter and height | About 5.6 mm across, low dome | Checked on the projector on the first article |
| Clearance hole | Typically 3.2 to 3.4 mm in the panel | Reviewed against the panel on the drawing |
| Tapped hole depth | Engagement for the joint | Set on the drawing; checked on the first article |
| Recess | Combination cross and slot | Checked with a PH bit and a flat blade |
| Length | From under the head to the tip | Measured on the shop plate |
Each size is quoted against the joint. On M3 the clearance hole, the tapped hole depth and the screw length are reviewed together, because a screw that bottoms in a blind hole stops before the head bears, and the whole clamp is lost without any visible sign.
Length is measured from under the head. For a joint into a blind tapped hole, the usable thread depth has to be at least the length minus the panel thickness; the drawing states both so the two cannot be confused.
M3 is the size where small equipment stops being delicate. Below it, the drive and the thread become the limiting features; at M3 there is enough material for a real head, a usable recess and a thread that survives a few assembly cycles.
| Parameter | Why it matters at M3 | What we control |
|---|---|---|
| Head diameter | Bearing area on the panel | Checked on the first article |
| Recess size | Bit engagement in a small head | Checked with both tools |
| Thread pitch | 0.5 mm coarse; threads per length | Gauged per batch |
| Head height | Clearance above the panel | Measured from the bearing face |
| Class | Torque the head can take | Confirmed on the certificate |
Torque is where M3 is most often over-estimated. The head is small, and a combination drive has less material in it than either a pure cross or a pure slot; over-driving deforms the recess long before the thread fails. The first article is driven at the joint torque with the tool the customer uses.
The bearing face does the load spreading. On a thin panel M3 with a pan head is a sensible pairing: the head is wide enough to spread the clamp over more than the thread diameter, so the sheet does not dish around the hole as it would under a small socket head.
Re-usability matters at this size. An M3 machine thread in a tapped insert can be taken out and refitted several times without damage, which is why it is used on enclosures that are opened for service rather than on joints that are made once.
This M3 pan head machine screw is supplied nickel plated. The deposit is hard and thin, and it keeps the small head looking clean — which matters because at this size the head is the most visible part of the assembly.
| Finish | How it protects | Effect on head and recess | Typical use |
|---|---|---|---|
| Nickel plated | Hard barrier layer, bright | A few microns; recess driven after plating | Visible small assemblies |
| Zinc plated | Sacrificial zinc layer | A few microns; gauged after | Indoor assemblies, low cost |
| Zinc nickel | Alloy layer, higher corrosion resistance | Thicker; thread re-checked | Wet or mildly corrosive service |
| Black oxide | Conversion layer plus oil | No build-up | Dark indoor parts |
| Stainless (equivalent part) | Alloy provides protection | No coating | Wash-down and outdoor work |
Hydrogen embrittlement applies here if the class is high. Zinc and nickel plating generate hydrogen at the steel surface, and a small high-class screw is exactly where a delayed failure is hard to find; where the drawing calls for it, the parts are baked after plating and the bake is recorded.
Packing protects the small heads and the recesses. The parts are bagged in counted quantities, labelled with the batch, the material heat and the drive type, and packed so the heads cannot rub.
Three assemblies where M3 is the practical size:
| Where it sits | The screw closes a cover or fixes a PCB bracket where the tapped insert is M3 and the head has to sit flat on a thin wall. |
| When it goes wrong | A screw that bottoms in the insert leaves the cover loose, and an over-driven recess deforms on the first assembly. |
| Why it happens | The wall is thin, the joint is serviced, and the screws are small enough to lose. |
| What we control | Thread class gauged, recess checked with the tool, and the length checked against the insert depth. |
| Where it sits | The screw holds a terminal cover, a DIN-rail accessory or a busbar connection where the joint carries current and is inspected. |
| When it goes wrong | A loose M3 joint heats up under load, and a stripped thread cannot be repaired in the field. |
| Why it happens | The assembly is electrical, the parts are small, and the joint is re-tightened during maintenance. |
| What we control | Both drives checked, thread gauged after plating, and the first article torqued in the joint. |
| Where it sits | The screw fixes a bracket, a sensor mount or a cover where a standard pan head clears the adjacent parts. |
| When it goes wrong | A head that is too tall fouls the next component, and a screw that is too long bottoms and stands off. |
| Why it happens | The parts are light, the clearance is tight, and the joint is adjusted. |
| What we control | Head height and thread length checked on the first article. |
Four reasons that matter at this size, each tied to what the drawing has to prove:
|
Thread, holes and length reviewed together
The M3 thread, the clearance hole, the tapped depth and the length are reviewed before tooling, so a screw that bottoms or stands off is raised first. Basis: Thread, holes and length reviewed before tooling. |
Head and drive in one route
The pan head and the combination recess are formed in one heading operation, so the drive stays centred in a small head. Basis: One heading operation for head and drive. |
|
Both drives and the thread checked
The recess is checked with a PH bit and a flat blade, and the thread is gauged in its plated condition, on the first article. Basis: First article checked with both tools. |
First article to repeat production
The first article fixes the drawing revision, wire heat, die set and plating batch; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these M3 pan head machine screws on a heading machine that upsets the pan head and the combination recess in one operation, then rolls the M3 machine thread and applies the nickel plating. The first part of every run is measured on the head, driven with both tools and gauged on the thread before the batch continues.
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Between runs the insert is changed to the drawing head and recess, and the thread rolls to the 0.5 mm pitch; the first part goes to the projector, to both bits and to the gauges. At this size the recess is the feature most sensitive to the plating, so the first plated part is driven before the run is packed.
What decides whether an M3 pan head machine screw passes is the head diameter and height, the recess in both drive configurations, the thread class after plating and the finish. The inspection agreement covers those, and the criteria come from the drawing.
Head and recess on the projector |
Thread gauged after plating |
Hardness testing against the property class |
Salt-spray testing of the plated part |
Each batch is recorded against the drawing revision: head and recess from the first article, the thread gauged after plating, and the coating batch carried on the label. If either drive or the thread check fails, the parts back to the last good setting are held and re-checked.
A report from an outside laboratory, where one is required, is organised before the batch runs so it can be filed under the same batch number.
Every shipment of M3 pan head machine screws is traceable to the wire it was made from. The grade, heat number and property class are recorded on the material certificate supplied with the parts, and the inspection records follow the criteria agreed on the drawing.
ISO 9001:2015 |
RoHS test report |
Registered trademark |
Patent: security screw and driver |
With each batch we supply the material certificate, the inspection record for the criteria on the drawing and, where it is listed, the third-party report for the material or the finish. The documents carry the drawing revision and the batch number, so the paperwork can be matched to the parts.
More than 8,678 customers in 89 countries and regions have ordered from Shi Shi Tong; 87% of orders come from repeat customers and 56% through referrals. Most projects follow the same route: drawing review, first-article approval, then batches checked against that sample. On M3 the first article is driven into the customer’s insert, so the thread class and the recess are signed off in the joint. Buyers visit during the process to review samples and to see how the heads are formed.
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8,678+
customers served
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87%
of orders from repeat customers
|
56%
of orders through referrals
|
89
countries and regions shipped to
|
Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the header and the plating line can be seen on the day the parts run.
Customer group visit – sample review |
Customer group visit – process discussion |
Customer group visit – factory tour |
Customer visit – project kick-off |
Danish customer – drawing review |
Industry exhibition – meeting customers |
It is a metric machine screw with a 3 mm nominal thread and a low domed head with a flat bearing face. This one is carbon steel with a nickel finish and a combination cross-and-slot drive.
0.5 mm on the coarse metric thread. The thread is rolled, so the pitch is held along the full length, which matters on short joints with only a few engaged threads.
Typically 3.2 to 3.4 mm for M3. The exact size depends on the fit the drawing calls for; the head diameter and the hole are reviewed together.
Yes, in a tapped insert or nut within its thread class. That is one reason M3 is used on enclosures that are opened for service rather than on joints made once.
Slightly, because the cross and slot share the same head material. What it buys is that either a Phillips bit or a flat blade will drive it, which reduces stripped heads in service.
Thread size and pitch, head diameter and height, drive type and size, length and datum, panel thickness, tapped hole depth, material and property class, and finish.
How an M3 pan head machine screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
Thread, holes and length review
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→ |
3
First article in the joint
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→ |
4
Batch production and repeat orders
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Each step is confirmed with you before the next one starts; the drawing revision from the first article is what repeat orders are checked against.
For a quotation, send the drawing with the thread size and pitch, head diameter and height, drive type and size, length and its datum, panel thickness, tapped hole depth, material and property class, and finish.
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Thread and pitch
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Head diameter and height
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Drive type and size
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Length and datum
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Panel and tapped depth
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Material and finish
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Sending a drawing? The form below does not take attachments. Email the PDF, DXF or STEP file to sst@szsst88.com with the part name and quantity in the subject line – the drawing is reviewed and a quotation follows.
+86 13143444311
sst@szsst88.com
