Tel：
+86 13143444311
Email：sst@szsst88.com
Fax：+0086-755-27322278
Address：Building 9, First Industrial Zone, Tantou Industrial City, Songgang Street, Baoan District, Shenzhen 518105, Guangdong, China
Type:Special oval cup head stainless steel screws
Materials:Stainless steel
Surface treatment:Plain
Head Type:oval cup head
Drive type:None (no slot; per drawing)
Thread:Partial (half) machine thread, chamfered end
Forming:CNC turning (bar stock)
Number:1546
We manufacture machine stainless steel screws with an oval cup head, a relieved shank and a chamfered partial machine thread, turned from stainless bar and passivated. Head diameter and oval angle, shank relief, thread class and length are made to your drawing.
Watch the factory video·Email sst@szsst88.com
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 machine stainless steel screw is a screw with a machine thread that engages a tapped hole or a nut, made in stainless so the corrosion resistance comes from the alloy rather than from a coating. The one on this page carries an oval cup head with no recess, a relieved shank and a partial thread with a chamfered end, turned from stainless bar to drawing.
Oval cup head. The head is a dome over a conical underside, so it sits into a countersink and leaves a smooth, decorative profile above the panel. The cone has to match the countersink angle; the dome is what the customer sees.
No recess. The head carries no slot and no socket, so the drive is defined on the drawing rather than on the part. Where a slot, a cross or wrench flats are needed, the head geometry and the tooling are reviewed together before the first bar is cut.
Relieved shank and partial thread. The thread runs only over part of the length, and the plain shank behind it is relieved to clear a bore. The chamfer at the tip starts the thread squarely in the tapped hole instead of cross-threading on the first turn.
Together these decide the fit: the oval head seats in the countersink, the relieved shank clears the bore, and the machine thread engages the tapped hole the drawing specifies.
On this machine stainless steel screw the body is turned from stainless bar, supplied plain and passivated. The grade and temper come from the drawing, and the bar arrives with its mill certificate so the heat number stays traceable to the parts.
The oval cup head is turned in the same set-up as the shank, so the dome, the cone and the bearing line sit on the screw axis. A head that is turned in a second operation can sit a few degrees off, and on a decorative oval head that shows as a gap on one side of the countersink.
The thread below the head is a machine thread, cut or rolled to the drawing, and the relieved shank diameter is held so the part slides into its bore without binding. The chamfer at the tip is cut to the thread minor diameter, which is what lets the screw start straight.
Plain stainless is the standard finish because it adds no thickness. Passivation restores the chromium film after turning without changing the head profile or the thread, so the part that ships is the part that was measured.
Machine stainless steel screws of this type are quoted in metric sizes from M2 to M10 and in lengths up to 150 mm, with the head profile measured on the projector and the thread gauged. Where a long version is required, custom lengths up to 2,000 mm are subject to DFM review after drawing submission.
| Item | How it is defined | What we control |
|---|---|---|
| Head diameter and height | The oval dome and its height above the panel | Checked on the projector on the first article |
| Oval angle | The conical underside that seats in the countersink | Checked against the countersink on the drawing |
| Shank relief | The plain diameter that clears the bore | Measured with micrometers on the first article |
| Thread size and length | Machine thread over the drawing length | Gauged per batch in the passivated condition |
| Chamfer | The lead at the tip that starts the thread | Checked on the projector and at assembly |
| Total length | From the top of the oval head to the tip | Datum stated on the drawing; measured on the shop plate |
Each size is quoted against the joint it closes. The countersink angle, the panel thickness and the head height are reviewed together, because an oval head that is right for one panel stands proud in another even at the same nominal size.
Head height is measured from the bearing line under the cone, and the total length from the top of the dome. The batch is checked on the features the process can drift on: head profile, shank relief and thread class.
The oval cup head is the feature that makes this machine stainless steel screw different from a standard pan or cap head. It has a domed top and a conical underside, and the cone is what seats in the panel countersink. The dome then stands slightly above the surface, which is why the head is used where the screw is meant to be seen.
Angle match decides whether it seats. An oval head made to 90 degrees in a 82 degree countersink only touches on one ring and rocks; the same head in a steeper countersink sinks too far and the dome no longer reads as a dome. The drawing states the angle, and the first article is checked against the mating part rather than against a chart.
The head carries no recess. That removes the usual way of driving the screw, so the drive is a separate agreement: where the joint allows, the part is turned by hand or with a soft fixture that grips the shank; where it does not, a slot, a cross or flats are added to the head and the tooling is changed. Either way the drawing states it, and the first article confirms the tool.
| Head feature | Why it matters | What we control |
|---|---|---|
| Dome radius | The visible profile above the panel | Checked on the projector |
| Cone angle | Seats in the countersink without rocking | Matched to the countersink on the drawing |
| Head height | Sits at the agreed line above the surface | Measured from the bearing line |
| Drive | No recess on the recorded part | Drive method fixed on the drawing and confirmed at first article |
This machine stainless steel screw is supplied in plain stainless, passivated. Plain matters on an oval head because the dome is the visible face: a coating that builds unevenly shows as a colour or sheen difference across the curve, and a thick coating can round off the edge where the dome meets the cone.
| Finish | How it protects | Effect on head and thread | Typical use |
|---|---|---|---|
| Passivated stainless | Free iron removed, passive film restored | No dimensional change | Stainless parts in damp service |
| Electropolished | Surface levelled, chromium enriched | Dome brightened; edge softened | Visible decorative heads |
| Black oxide (carbon steel) | Conversion coating, minimal thickness | No measurable build-up | Indoor parts where black is required |
| Zinc plated (carbon steel) | Sacrificial zinc layer | Build-up on thread; gauged after | Carbon steel equivalents |
| Dacromet flake (steel) | Zinc-aluminium flake layer | Thin film; thread checked over coating | Outdoor carbon steel parts |
Salt-spray exposure is agreed per project and written on the drawing; passivated stainless is tested in the condition it ships in. On a decorative oval head the finish is also checked against the sample under agreed light, because a dome shows a sheen difference that a flat surface hides.
Packing protects the domes. Screws are packed in layers so the heads do not rub, and the label carries the batch, the material heat and the finish reference.
Three assemblies where an oval cup head machine stainless steel screw is chosen for the exposed head, and what the screw has to do instead:
| Where it sits | The screw closes a countersunk cover on an instrument housing, where the oval head is part of the visible face. |
| When it goes wrong | A cone that does not match the countersink rocks, and a dome that is a shade off reads as a mismatched batch. |
| Why it happens | The cover is thin, the screw is visible, and the housing is opened for service. |
| What we control | Cone angle matched to the countersink, dome profile checked on the projector, and the finish compared with the sample. |
| Where it sits | The screw fastens a decorative panel or a badge where the head sits in a countersink and the dome shows. |
| When it goes wrong | A head that stands proud catches on a cleaning cloth or a moving part, and a burr at the cone edge marks the panel. |
| Why it happens | The panel is painted or brushed, the screw is exposed, and the joint is not re-opened often. |
| What we control | Head height and edge burr checked, and the dome polished and passivated before packing. |
| Where it sits | The screw holds a stainless fitting on a boat or an outdoor cabinet, where salt and rain reach the joint. |
| When it goes wrong | A carbon steel screw rusts at the dome within a season, and a thread that galls seizes in the tapped hole. |
| Why it happens | The parts are stainless, the environment is wet, and the joint is assembled once and left. |
| What we control | Stainless grade and passivation recorded, thread gauged, and salt-spray exposure agreed per project. |
Four reasons that matter on a machine stainless steel screw with an oval cup head, each tied to what the drawing has to prove:
|
Head angle reviewed with the countersink
The oval angle, the head height and the countersink on the panel are reviewed before the bar is cut, so a head that would rock is raised with you first. Basis: Head angle and countersink reviewed before turning. |
Turned and threaded in one route
The oval head, the relieved shank and the thread are produced on one turning route, so the dome, the cone and the thread stay on the same axis. Basis: One route for head, shank and thread. |
|
Head profile measured on the projector
The dome, the cone angle and the head height are measured on the optical projector, and the thread is gauged, in the passivated condition. Basis: Head profile and thread measured in the finished condition. |
First article to repeat production
The first article fixes the drawing revision, material heat, turning set-up and finish batch; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong turns these machine stainless steel screws from bar: the bar is cut and faced, the oval head and the cone are turned, the shank is relieved, the thread is cut and the tip is chamfered, all on the same route so the datum does not change. The first part of every run is measured on the head and gauged on the thread before the batch continues.
Bar checked before the first cut |
Threads gauged after passivation |
Between runs the lathe is set to the drawing head angle and thread size; the first part goes to the projector and the gauges before the run continues, and the setting is recorded. Decorative heads are packed so they do not rub against each other before they reach the assembly.
What decides whether a machine stainless steel screw passes is not the polish on the dome: it is the head profile and cone angle, the relieved shank diameter, the thread class and the chamfer at the tip. The inspection agreement covers those, and the criteria come from the drawing.
Thread gauging against GO/NO-GO gauges |
Oval profile and cone angle on the projector |
Hardness testing where the drawing requires it |
Salt-spray testing of the passivated finish |
Each batch is recorded against the drawing revision: head profile and cone from the first article, the relieved shank measured, and the thread gauged per batch. If a gauge or the head 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 machine stainless steel screw shipment is traceable to the bar 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 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. Decorative heads are approved against a countersink sample, so the cone angle and the dome are signed off together. Buyers visit during the process to review samples and to see how the heads are turned and passivated.
|
8,678+
customers served
|
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 turning cells and the passivation 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 screw with a machine thread that engages a tapped hole or a nut, made in stainless steel so the corrosion resistance comes from the alloy. This one has an oval cup head, a relieved shank and a chamfered partial thread.
A domed head with a conical underside. The cone seats in the panel countersink and the dome stands slightly above the surface, so the head is used where the screw is meant to be seen.
The drive is defined on the drawing. Where the joint allows, the part is turned by hand or with a soft fixture on the shank; where it does not, a slot, a cross or flats are added to the head and the tooling is reviewed before production.
Machine stainless steel screws of this type are quoted in metric sizes from M2 to M10 and in lengths up to 150 mm. Where a long version is required, custom lengths up to 2,000 mm are subject to DFM review after drawing submission.
The plain shank runs through a bore before the thread engages, so it is turned slightly under the thread diameter to clear the bore without binding. The relief diameter is on the drawing and measured on the first article.
Oval head diameter, height and cone angle, the mating countersink, shank relief, thread size and length, chamfer, total length and datum, material, finish and the drive method.
How a machine stainless steel screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
|
→ |
2
Head and countersink review
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→ |
3
First article approval
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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 oval head diameter, height and cone angle, the mating countersink, the shank relief diameter, thread size and length, chamfer, total length and datum, material, finish and the drive method.
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Head diameter, height and angle
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Mating countersink
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Shank relief
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Thread size and length
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Chamfer and total length
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Material, finish and drive
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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
