Stainless Steel Allen Grub – Flat Point

What is an Allen grub – flat point & when to use it?

An Allen grub screw (socket set screw) – flat point is a headless screw with an internal hex (Allen) drive and a flat end face (no cone, no cup).

Use a flat point grub screw when you want to:

Lock or position parts but with minimal marking or damage on the mating surface

Bear against a flat surface (e.g. flats on shafts, keys, pads, inserts)

Keep the fastener completely recessed inside a tapped hole (no head projection)

Typical applications:

Locking collars, knobs, levers against a shaft flat

Adjusting stops and end positions (limit screws, stop screws)

Clamping on softer surfaces where cones/cups would dig in too aggressively

Repeated adjustments where you don’t want deeper and deeper indentations each time

Flat point = gentlest contact of all grub screw styles.

2) Environment & corrosion

Indoor / dry / general machinery:

Use hardened alloy steel flat point grub screws, black / oiled finish.

Ideal for adjustment screws, collars, knobs, stops on mild steel components.

Outdoor / damp / mild chemical exposure / stainless assemblies:

Use A2 (304) stainless flat point grubs.

Good for stainless shafts, outdoor equipment, food equipment (non-marine).

Marine / chloride / strong chemical / wash-down:

Use A4 (316) stainless flat point grubs.

Best for marine shafts, coastal mechanisms, chemical and wash-down areas.

Rule of thumb:

Priority = strength & hardness in dry conditions → alloy steel

Priority = corrosion resistance in wet/chemically aggressive conditions → A2 / A4 stainless

3) Point style – why flat point vs cup / cone / dog?

Flat point (your product here):

End face is flat, making full-face contact with the mating surface.

Gives gentle, non-cutting pressure rather than penetration.

Ideal when you:

Want to avoid deep marks in a shaft

Are bearing on a machined flat, key, pad, or insert

Need frequent adjustment without progressively damaging the surface

Compared to:

Cup point:

Biting edge, more grip, more surface indentation.

Good general lock on plain shafts.

Cone point:

Sharp tip, maximum penetration and grip, maximum surface damage.

For high-torque, high-vibration, more permanent locking.

Dog point:

Cylindrical tip fits into holes/slots for positive index.

So, if the customer says: “It must hold, but I don’t want to destroy or crater the surface” → flat point is the right style.

Mechanical Properties (Guide) – Allen Grub Screw – Flat Point

Set screws (grub screws) are typically made either from hardened alloy steel or from stainless steel. Flat point versions share the same body properties as cup/cone, but with a different tip geometry.

1) Alloy steel flat point grub screws (hardened)

Typical characteristics:

Manufactured from medium or alloy steel, heat treated and tempered.

Often supplied to hardness around 45H (per set-screw standards), meaning:

Surface hardness in the mid-40s to low-50s HRC range

High tensile and shear strength for the threaded section

Functional behaviour:

Very good resistance to thread stripping and bending.

Flat tip is less likely to cut or gouge the surface, but still gives a solid, non-deforming contact area.

Ideal for industrial machinery where high strength and repeated adjustments are required.

2) Stainless steel flat point grub screws (A2 / A4)

Typical characteristics:

Material: A2 (304) or A4 (316) stainless steel.

Lower hardness than fully hardened alloy steel, but with:

Good tensile strength (A2-70 / A4-70 ≈ 700 MPa)

Excellent corrosion resistance for appropriate environments

Functional behaviour:

Best wherever rust and staining must be avoided (stainless shafts, food processing, marine, outdoor).

Flat tip distributes load more gently on polished or corrosion-sensitive surfaces.

3) Functional performance & limits

For a correctly sized and installed flat point grub screw:

Holding function is a mix of:

Normal force from tightening,

Frictional resistance at the flat contact,

Any geometric support (like shaft flats or keys).

Flat point is not intended to dig in like cone/cup points, so for purely friction-based grip on a round shaft, its holding power is limited.

Typical failure/slip scenarios:

Screw loosens under vibration if not tightened correctly or without thread-locker.

Friction slip between flat point and shaft if the contact surface is smooth, especially at high torque.

Thread stripping in the hub if engagement length is inadequate or material is too soft.

Good practice:

Use thread-locker for vibration-prone assemblies.

Use shaft flats, keys, or pads rather than relying solely on friction on a round shaft.

Don’t overtighten small grub screws; use appropriate torque and correct Allen key.