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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:316 stainless self tapping screw (pan head, combination drive)
Materials:Stainless steel 316
Surface treatment:Plain, passivated
Head Type:Pan head
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Drive:Combination Phillips and slot
Thread:Self tapping, partial thread, blunt point
Forming:Cold heading; thread rolled, then passivated
Number:339
We manufacture 316 stainless steel self tapping screws with a pan head, a combination cross-and-slot drive and a partial thread with a blunt point, quoted from M1 to M14. Grade, thread, plain shank length, point and pilot size 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.
A 316 stainless steel self tapping screw is a screw that forms its own mating thread in the material it enters, made from the molybdenum-bearing grade rather than the standard 304. The recorded item on this page is a pan head screw with a combination cross-and-slot drive, a partial self-tapping thread and a blunt point, supplied plain and cleaned.
316 grade. The molybdenum in the alloy is what separates it from 304: it improves resistance to chlorides, so the screw survives salt spray, seawater splash and chloride-bearing wash-down chemicals that would pit a 304 part over time.
Self-tapping thread. The thread forms its own mating thread in a pilot hole, so no nut and no tapped insert are needed. On this part the thread is on the leading section only, with a plain shank under the head.
Blunt point. The point is not a gimlet; it is intended to enter a prepared pilot or cored hole. That suits sheet metal and moulded parts where the hole has already been made by the panel manufacturer.
Combination drive. A cross recess with a slot through it, so the screw can be driven with a Phillips bit on a line or a flat blade during service.
Together these decide the joint: the grade survives the environment, the self-tapping thread forms its own grip, the blunt point suits a prepared hole, and the combination drive matches whatever tool is at hand. That is why a 316 stainless steel self tapping screw is specified by grade, thread, point and drive together.
The body of this 316 stainless steel self tapping screw is 316 wire, with the heat number and the mill certificate kept with the batch record. The grade is stated on the drawing as well as in the title, because a customer comparing quotes will see 304 and 316 priced very differently and needs to know which one the specification actually calls for.
The pan head and the combination recess are formed in one heading operation. The cross and the slot share the same head material, so the walls between them are the thinnest part of the drive; the recess is formed rather than cut so those walls stay supported.
The self-tapping thread is rolled on the leading section, with a plain shank under the head. The thread form and the pilot size are specified together, because a forming thread in an undersized hole splits the sheet and a coarse thread in a thin gauge strips before the head seats.
The blunt point is formed on centre and sized to the pilot hole. It is not meant to start its own hole; it is meant to enter a hole that already exists and lead the first thread in square, which is why the pilot diameter appears on the drawing next to the thread callout.
The parts are passivated after forming. Passivation removes free iron from the surface and restores the chromium oxide film, and on a 316 part it is the film — not a coating — that does the corrosion work.
316 stainless steel self tapping screws of this type are quoted from M1 to M14; the recorded configuration covers that range with a pan head, a combination drive and a partial self-tapping thread. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission, because the thread and the point are set before the roll is made.
| Item | How it is defined | What we control |
|---|---|---|
| Head diameter and height | The pan head that bears on the panel | Checked on the projector on the first article |
| Drive | Combination cross and slot | Checked with a PH bit and a flat blade |
| Plain shank length | The section under the head that clears the top layer | Measured from under the head |
| Thread length and pitch | The grip in the lower layer | Gauged per batch |
| Point diameter | The blunt point that enters the pilot | Checked on the first article |
| Grade | 316, with 316L available where the drawing calls for it | Confirmed against the material certificate |
Each size is quoted against the joint it enters. The pilot hole, the thread pitch and the sheet gauge are reviewed together, because a 316 thread is harder to reform than a carbon steel one and a pilot that is wrong cannot be corrected by driving harder.
Length is measured from under the head, and the thread length from the tip. Both are on the drawing because the plain shank is what clears the top layer, and on a partial-thread screw that dimension decides whether the joint clamps or strips.
The grade is the feature that justifies the part. A 304 screw and a 316 screw look identical in a tray, and the difference only appears where chlorides are present: pitting, crevice corrosion around the head, and staining that runs down the panel. The molybdenum in 316 slows that down, which is what a coastal or wash-down joint needs.
| Parameter | Why it matters on this part | What we control |
|---|---|---|
| Grade | Chloride resistance in service | Confirmed on the material certificate |
| Thread form and pitch | Grip in the sheet without stripping | Matched to the sheet gauge |
| Plain shank length | Clears the top layer so the joint clamps | Measured from under the head |
| Blunt point | Enters the prepared pilot square | Checked on the first article |
| Combo recess | Either PH or flat blade drives it | Checked with both tools |
Stainless self-tapping screws work-harden the sheet as they cut. That is why the joint holds, and it is also why the hole cannot be reused: once the thread strips, the work-hardened hole has to be moved to the next size. The pilot size on the drawing is not a suggestion.
Stainless on stainless galls. Where the screw and the panel are both stainless, the surfaces can pick up and seize during driving, so the thread fit and the drive speed are part of the process. A combination recess helps here: a flat blade can usually break a seized screw free where a Phillips bit would cam out.
The blunt point and the partial thread are a pair. The point enters the pilot, the plain shank passes through the top layer, and only the leading thread engages the lower layer — which is what pulls the two sheets together instead of threading through both.
This 316 stainless steel self tapping screw is supplied plain and passivated, with no coating. On a chloride-resistant part a coating would be counterproductive: it adds a layer that can chip at the head edge and leave a crevice, which is exactly where pitting starts on stainless.
| Finish | How it protects | Effect on thread and head | Typical use |
|---|---|---|---|
| Plain, passivated 316 | Molybdenum-bearing passive film | No build-up; thread and head as formed | Coastal, chemical and wash-down joints |
| Electropolished 316 | Surface levelled, chromium enriched | A few microns removed; thread re-checked | Hygienic and visible stainless work |
| Bead blasted 316 | Uniform matte surface | No dimensional change | Panels where glare must be removed |
| Passivated 304 (lower grade) | Standard passive film | No dimensional change | Indoor and low-chloride service |
| Zinc plated steel (equivalent) | Sacrificial layer | Coating wears at the cutting edge | Indoor steel assemblies |
Passivation is not a coating and it does not hide a wrong grade. It removes free iron left by forming and lets the natural oxide reform; if the alloy is wrong for the environment, the part will still pit, and the certificate is the only way to know what was supplied.
Packing keeps the threads and points apart. The parts are bagged in counted quantities and labelled with the batch, the grade and the heat number, because a mixed bag of 304 and 316 is the most expensive mistake in this product line.
Three environments where the grade, not the thread, is the reason for the part:
| Where it sits | The screw closes a bracket, a panel or a trim piece on equipment that sees salt spray or seawater splash for its service life. |
| When it goes wrong | A 304 screw pits at the head and stains the panel; a plated one loses its coating and rusts from the scratch. |
| Why it happens | The joint is permanently exposed, the parts are visible, and the assembly is expected to stay intact without re-finishing. |
| What we control | Grade confirmed on the certificate, and the plain passivated surface checked before packing. |
| Where it sits | The screw holds a guard, a label plate or a cover on equipment where the atmosphere or the wash-down chemical carries chlorides. |
| When it goes wrong | Chloride pitting starts in the crevice under the head and works through the sheet, and the joint fails at the point nobody inspects. |
| Why it happens | The environment attacks most metals, the parts are checked on shutdown, and the joint has to come apart again. |
| What we control | Grade confirmed, thread gauged, and the surface kept clean from packing to assembly. |
| Where it sits | The screw fixes a panel or a bracket on stainless equipment that is cleaned with chlorinated or caustic chemicals. |
| When it goes wrong | A pitted screw traps residue and fails a hygiene inspection, and a coating that flakes becomes a contaminant. |
| Why it happens | The equipment is washed on a schedule, the surfaces are stainless, and the fasteners are inspected. |
| What we control | Grade and passivation confirmed, and the thread gauged so the joint can be re-torqued after cleaning. |
Four reasons that matter on a grade-specific stainless part, each tied to what the drawing has to prove:
|
Grade and joint reviewed together
The grade, the pilot size and the thread form are reviewed before the roll is made, so a screw that will gall or strip is raised first. Basis: Grade, pilot and thread reviewed before tooling. |
Headed and rolled in one route
The pan head and the combination recess are formed in the heading die and the partial thread is rolled, so the recess stays centred in the head. Basis: One route from wire to finished screw. |
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Thread and both drives checked on the part
The thread is gauged in its finished condition and the recess is checked with a PH bit and a flat blade, on the first article. Basis: First article checked with both tools. |
First article to repeat production
The first article fixes the drawing revision, heat number, die set and thread roll; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these 316 stainless steel self tapping screws on a heading machine that upsets the pan head and the combination recess in one operation, then rolls the partial self-tapping thread and forms the blunt point before passivating the parts. The first part of every run is measured on the head, the thread and the point, and driven into a sample of the sheet, before the batch continues.
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Stainless work-hardens as it is rolled, so the thread rolls are set for the grade and the first part is checked before the run continues. Between runs the die is changed to the drawing head and the rolls to the pitch; the point is checked on the same first part as the thread, because the two are formed in sequence and a fault in one shows in the other.
What decides whether a 316 stainless steel self tapping screw passes is the grade on the certificate, the head diameter and recess, the thread form and pitch, the plain shank length and the point. The inspection agreement covers those, and the criteria come from the drawing.
Head and thread start on the projector |
Thread gauged per batch |
Hardness testing where the drawing requires it |
Salt-spray testing of the passivated part |
Each batch is recorded against the drawing revision: head and thread from the first article, the grade and heat number on the certificate, and the drive type carried on the label. If the sheet sample or the gauge check fails, the parts back to the last good setting are held and re-checked.
Where a third-party report is required for the material, it is written into the drawing, the report ships with the parts and the label carries the same batch number as the inspection record.
Every shipment of 316 stainless steel self tapping screws is traceable to the wire it was made from. The grade, heat number and standard 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. 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 stainless self-tapping parts the first article is driven into a sample of the customer’s own sheet, so the thread and the point are signed off in the material they will cut. Buyers visit during the process to review samples and to see how the points are formed.
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8,678+
customers served
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87%
of orders from repeat customers
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56%
of orders through referrals
|
89
countries and regions shipped to
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Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the header and the inspection room 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 screw made from the molybdenum-bearing stainless grade that forms its own mating thread in a pilot hole. This one has a pan head, a combination cross-and-slot drive and a partial thread with a blunt point.
Because of chlorides. The molybdenum in 316 improves resistance to salt spray, seawater splash and chloride-bearing chemicals, so it pitting-resists where a 304 screw would stain and pit.
It enters a pilot or cored hole that has already been made and leads the first thread in square. It is not a gimlet point, so it is not intended to start its own hole in solid material.
So the plain shank clears the top layer and only the leading thread engages the lower layer, which pulls the sheets together as the head seats.
It can, when stainless meets stainless. The thread fit and the drive speed are part of the specification, and the combination recess lets a flat blade break a seized screw free.
Head diameter and height, drive type and size, thread size, pitch and length, plain shank length, point diameter, length and datum, grade (316 or 316L), finish, and the sheet gauge and pilot size.
How a 316 stainless steel self tapping screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
Grade, pilot and thread review
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→ |
3
First article in the sheet
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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 head diameter and height, drive type and size, thread size, pitch and length, plain shank length, point diameter, length and its datum, grade, finish, and the sheet gauge and pilot size.
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Head diameter and height
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Drive type and size
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Thread and plain shank length
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Point diameter
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Length and datum
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Grade, sheet and pilot
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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
