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:Slotted Oval Head Machine Screws
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Oval Head
Drive:Single slot
Thread:Machine thread
Point:Blunt
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:223
We make slotted oval head machine screws in passivated A2 stainless, with a countersunk cone, a domed top and a single slot, quoting them from M1 to M14. Slot width and depth, dome height, cone angle and grade come from your drawing, and the first article is driven with your blade.
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.
These slotted oval head machine screws have a raised countersunk head — an oval head — with a single slot, in passivated A2 stainless, quoted from M1 to M14 with Number 223. The cone seats in a countersink, the domed top stays slightly proud, and the slot is the drive.
Oval head. A 90-degree countersunk cone with a low dome above it, so the head seats but keeps a rounded face.
Single slot. One straight cut across the dome, driven with a flat blade.
Machine thread. A rolled thread for a tapped hole or a nut, ending in a blunt chamfer.
Passivated stainless. A2 grade, uncoated, so the slot and the cone are as made.
Slotted oval head machine screws are the form used where a domed, period-correct head is wanted and the joint is light: instruments, trim, and covers that a flat blade will close. They are not a high-torque fixing, and the slot is the reason.
A slotted oval head machine screw is the classic combination: a rounded head that seats in a countersink, and a single straight slot to turn it. Both parts of that combination are old, and both still work for the jobs they suit — instruments, trim, and equipment where a flat blade is the tool that is actually to hand.
On slotted oval head machine screws the slot is the limit. It offers two driving faces instead of the four of a cross or the six of a star, and it is cut across a dome, so the blade bears on the top of the curved face. A blade that is too thin spreads the slot, one that is too thick does not reach the bottom, and either way the load lands on the thinnest part of the head.
On these screws the dome is what makes the head look right, and it is also what makes the slot shallow. On a flat countersunk head the slot can be cut deep because the face is flat; on an oval head the face curves away, so the slot is shallower at its ends than in the middle. That is why these screws are used for light joints rather than for anything that has to be tightened hard.
On slotted oval head machine screws the cone still carries the joint. It seats in the countersink, centres the screw and takes the clamp, and its angle has to match the seat; on an oval head a mismatch shows as a visible tilt, because the dome magnifies what a flat head would hide.
For slotted oval head machine screws stainless suits the finish. There is no coating to fill the shallow slot or to change the seat, and on a part that is often visible the bare alloy keeps the same appearance after handling — which on a classic-style screw is most of the point.
The recorded range is M1 to M14, with lengths made to the drawing. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For slotted oval head machine screws the quotation carries head diameter, dome height, slot width and depth, cone angle, overall length and grade.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Raised countersunk, domed | Head diameter and dome height |
| Slot | Single straight cut | Slot width, depth and end radius |
| Cone | 90-degree seat | Cone angle and contact |
| Length | Overall, head included | Length tolerance and end chamfer |
| Thread | Machine thread | Pitch, length and gauging |
| Material | A2 stainless | Grade and heat number on the certificate |
| Finish | Passivated | Surface condition and slot edges |
Slot width belongs on the drawing against the blade the customer uses. On an oval head the slot is the whole drive, and a slot that is a hundredth off either way is a blade that rocks or a blade that will not enter.
Dome height is the other number to quote. On a screw that seats in a countersink, the dome is what stands above the surface, and a cover or a mating part has to clear it.
Three features define the part: the oval head, the single slot and the stainless body. The first gives the classic appearance, the second is the drive, and the third keeps the slot and the seat as made.
| Feature | What it gives | What it costs |
|---|---|---|
| Oval head | A rounded, finished face | Stands above the surface |
| Single slot | Any flat blade will turn it | Two drive faces; limited torque |
| Slot in a dome | Deep in the middle, shallow at the ends | Blade bears on a curved face |
| Cone seat | Centres the screw as it tightens | Angle and depth must match |
| Passivated A2 | Slot and cone as made | Galls dry against stainless |
The classic look is the reason the form survives. On restored instruments, period furniture and equipment that is meant to look of its age, a slot and a dome are the correct details, and a cross recess would be the wrong one however much easier it is to drive.
The cost is torque. A slot across a dome is a weak drive, and these screws should be used where the joint is light and the blade is a good fit; forcing them rounds the slot and then nothing will turn them.
The recorded finish is passivation with no coating on A2 stainless. On a slotted head that matters twice: a coating would narrow a slot that is already shallow at its ends, and it would round the dome, which is the face the part is bought for.
| Option | How it protects | Effect on slot and dome | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | Slot and dome as made | Instruments and trim |
| A4 stainless, passivated | Passive film with molybdenum | Slot and dome as made | Marine and medical |
| Brass, plain | No coating needed | Softer slot; wears at the edges | Decorative and period work |
| Steel, nickel plated | Barrier deposit, bright | Slot slightly narrowed | Visible indoor fittings |
| Steel, zinc plated | Sacrificial zinc | Slot narrowed; re-checked | General indoor work |
Where the part is period-correct, brass is the traditional material and takes a patina that stainless cannot. The trade is softness: a brass slot wears at the edges, and after a few removals the blade no longer seats.
Where the joint is wet, A4 is the grade and the slot is the reason: a rusted slot on an uncoated screw is a screw that cannot be turned, and there is no other drive to fall back on.
Three assemblies where slotted oval head machine screws are the fixing:
| Where it sits | The screw holds a plate or a trim where the fixing has to match the original style and a flat blade is the tool in use. |
| When it goes wrong | A blade that is too thin spreads the slot, and the screw can no longer be turned. |
| Why it happens | The joint is visible, it is period-correct, and the drive is a slot. |
| What we control | Slot width matched to the blade; first article driven and released. |
| Where it sits | The screw seats in a countersink on a visible face where a domed head reads as a detail rather than as a fixing. |
| When it goes wrong | The dome is marked, or the slot chips and the edge looks worn. |
| Why it happens | The joint is decorative, the head is seen, and it is assembled by hand. |
| What we control | Dome height and slot checked; first article fitted on the piece. |
| Where it sits | The screw holds a cover where the joint is light and the seat is shallow, and a slot is enough to tighten it. |
| When it goes wrong | A slot forced with a blade that does not fit rounds and the cover cannot be removed. |
| Why it happens | The joint is light, the seat is shallow, and the head is visible. |
| What we control | Cone angle and slot checked; first article assembled. |
Four reasons that matter on a slotted domed head, each tied to what the drawing has to prove:
|
Slot and dome agreed
Slot width and depth, dome height and cone angle are agreed as a set, because on a domed head the slot has to fit inside the curve. Basis: Slot and dome agreed. |
Formed, slotted, passivated in one route
The cone and dome are formed in one stroke, the slot cut and the thread rolled before passivation. Basis: One route from wire to passivated screw. |
|
Slot checked with the blade
The first article is turned with the customer blade and checked that it reaches the bottom of the slot without rocking. Basis: Slot checked with the blade. |
Dome height recorded
The dome height is recorded from the first article, because it is what stands above the customer surface. Basis: Dome height recorded. |
Shi Shi Tong forms the cone and dome of these screws in one stroke, cuts the single slot with a radiused cutter, rolls the machine thread and passivates the parts. The first part of every run is measured on head diameter, dome height, slot width and depth, cone angle and thread before the batch continues.
|
|
Cutting a slot across a dome is where the part is decided. The cutter has to hold its depth while the face curves away under it, so the slot is shallower at the ends than in the middle; a cutter that is slightly high leaves ends so shallow that the blade rides up, and the screw looks right and cannot be turned.
What decides whether slotted oval head machine screws pass is the slot, the dome, the cone and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Slot and dome on the projector |
Thread gauged per batch |
Hardness checked on the wire |
Salt-spray testing of the grade |
The slot is checked for width at the top and at the base, for depth, and for the radius at each end; the dome for height and evenness, and the cone for angle and contact. The thread is gauged per batch, and the slot edges are checked for burrs that would catch a blade.
The first article is turned with the customer blade and released. A slotted screw that drives and will not release is a screw that has to be drilled out, and on a domed head there is nothing to grip.
Every shipment of slotted oval head machine screws is traceable to the wire it was made from and to the passivation batch. The grade and heat number 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 grade. The documents carry the drawing revision and the batch number, so a repeat order keeps the same slot and dome.
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 a slotted oval head screw the first article is turned with the customer blade, because the slot is the whole drive. Buyers visit during the process to review samples.
|
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 slotting and passivation lines 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 |
The slot is cut across a dome, so the face curves away. The blade seats in the middle, and the ends are always shallower.
On period equipment and trim the slot is the correct detail; a cross would be the wrong one however easier it is to drive.
Less than a cross or a star. A slot has two drive faces, and on a domed head the blade also sits on a curve.
One that is wide enough to fill the slot and thin enough to reach the bottom. A force fit spreads the slot.
No. The cone seats, but the dome stands above the surface by the dome height, which is quoted on the drawing.
Head diameter and dome height, slot width and depth, cone angle, overall length, thread and the grade.
How a slotted oval head screw project runs from drawing to repeat delivery:
|
1
Send the drawing and the blade you use
|
→ |
2
Slot, dome and cone agreed
|
→ |
3
First article driven and released with your blade
|
→ |
4
Batch production and repeat orders
|
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 dome height, slot width and depth, cone angle, overall length, thread and the grade.
|
Head diameter
|
Dome height
|
Slot width
|
|
Slot depth
|
Cone angle
|
Grade
|
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
