Square Hole Chipboard Screw with Serrated Thread
Copper-coated chipboard screw with a square drive and a serrated cutting thread.
This is the square-drive member of the chipboard family. The square recess, sometimes called Robertson, holds a bit by friction on four flat walls and will keep a screw on the end of a driver at any angle, which is why it survives in furniture assembly and deck work where the operator has one hand for the screw and one for the panel.
The serrated thread does the second half of the work. Interrupting the thread reduces the driving torque in particleboard and MDF noticeably, so the head seats before the panel core starts to crumble. The old listing shows this item in a copper-toned coating.
Why buyers choose it
- Square drive grips the bit without magnetism and works at an angle
- Serrated thread cuts board fibre instead of compressing it
- Double countersunk head with ribs seats cleanly into panel faces
- Copper-toned coating for applications where the head is visible
Send the panel or masonry you are fixing into, the drive you run and the head finish and the size will be confirmed against the closest standard before quoting. Samples of this item are free of charge.
Specification
| Standard | ASME, ASTM, IFI, ANSI, DIN, BS, JIS |
|---|---|
| Material | Carbon Steel, Alloy Steel |
| Grade / Class | 4.6, 4.8, 5.6, 8.8, 10.9, SAE J429 Gr. 2, Gr. 5, Gr. 8, A307 A/B, A394, A449 |
| Thread | M, UNC, UNF, BSW |
| Finish | Self Colour, Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black Oxide, Nickel, Chrome, HDG |
| Packing | 15 KGS/CTN, 48 CTN/Solid Wood Pallet |
| Loading Port | Shanghai or Ningbo |
| Minimum Order | 500 kg |
| Payment | T/T, L/C |
| Samples | Free of charge |
| Main Markets | EU, USA, Canada, South America |
Specification as published by Haiyan Ehons Industrial Co., Ltd.. Head diameter, rib pattern and drive size are all quotable against a panel sample.
Technical detail
| Standards | Produced to ASME, ASTM, IFI, ANSI, DIN, BS and JIS references. |
|---|---|
| Material | Carbon steel or alloy steel. |
| Grade class | 4.6, 4.8, 5.6, 8.8 and 10.9; SAE J429 Gr.2, Gr.5 and Gr.8; ASTM A307 A/B, A394 and A449. |
| Drive | Square recess. |
| Finish | Self colour, plain, zinc plated in clear, blue, yellow or black, black oxide, nickel, chrome and hot dip galvanised. |
Problems this screw solves
Bits fall off the screw
A square recess wedges the bit. Screws stay on the driver overhead and at awkward angles without a magnetic holder.
Board splits at the edge
A continuous thread acts as a wedge in particleboard. The serrated form cuts a path and reduces the hoop stress that splits an edge.
Driving torque stalls the tool
Interrupted threads cut driving torque, which matters on a production line running a fixed-torque driver all day.
Where it is used
- Flat-pack and cabinet assembly in chipboard and MDF
- Deck and joinery work where one-handed screw placement is normal
- Fixing panel products to timber sub-frames
- Repair and re-fixing work where a Phillips recess has already failed
Who buys it
Furniture manufacturers, joinery shops and panel fabricators, plus merchants supplying square-drive screws into markets where that drive is the local standard.
Quality control priorities
Square recess corner radius is the dimension that decides whether a bit locks or rounds out, and it is gauged on samples through the run. The serration pattern is inspected visually for full formation on every thread segment.
Customisation
Head diameter and rib count under the flange can be adjusted where the panel face is a thin laminate that a standard rib pattern would lift. Send a panel sample with the enquiry if the surface is delicate.
How it compares
Against the yellow zinc chipboard screw
Same family and the same underhead idea; this one substitutes a square drive and a serrated thread where driving torque or bit retention is the constraint.
Against a Torx chipboard screw
Torx transmits more torque; square retains the bit better without magnetism. The choice is usually about which bits the customer already runs.
Against the concrete screw with serrated thread
Same thread principle, different substrate and hardness. Do not substitute one for the other.
Installation notes
Use a matched square bit
Square drives come in numbered sizes. A loose bit will round the recess corners in one screw.
Pilot near edges
Within about 50 mm of a panel edge, a pilot hole is cheap insurance even with a serrated thread.
Set torque, not speed
Fast driving generates heat in MDF and glazes the hole. A moderate speed with a firm torque limit seats better.
Match the coating to the visible face
Where the head shows, order the coating with the screw rather than painting afterwards.
Frequently asked questions
What drive size do these take?
Are these for concrete?
Can I have a different coating colour?
What is the minimum order?
How are they packed?
Do you supply free samples?
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Packed 15 KGS/CTN, 48 CTN/Solid Wood Pallet. Loading at Shanghai or Ningbo. Minimum order 500 kg for this item.