Knurled Head Screws Manufacturer in India | Knurled Head Thumb Screws

Overview

Knurled Head Thumb Screws DIN 464 & DIN 653: Manufacturer & Supplier

A knurled head screw has a wide, ridged head that the fingers can grip and turn. It is made for parts that are opened, adjusted or changed often, where fetching a tool would slow things down.

Exotic Alloy manufactures knurled head screws in Mumbai, India, for instrument, laboratory, fixture, electronics and machine builders. We stock across India and supply Chile, South America, the Gulf and Europe. Heads are knurled, threads rolled or cut, and finishes applied to suit the use.

High or low

The DIN 464 high type stands on a collar, so the fingers get under the knurl easily; it is made plain or with a slot. The DIN 653 low type keeps the same knurled head but sits directly on the part. For wing and other finger-turned screws see thumb screws and butterfly screws.

DIN 464 high DIN 653 low Slotted option M1 to M10 Stainless & brass

Knurled head screw at a glance

Head: Straight-knurled disc, about twice the thread size or more
Types: High with collar (DIN 464), low (DIN 653)
Drive: Fingers; slot for a screwdriver (option)
Length: From under the head or collar
Clamp: Light: hand torque only
Related: Thumb screws, butterfly screws, knurled nuts

DIN 464 M5 × 16 knurled thumb screw, high type with slot, drawn to scale. Knurl and thread shown schematically; top view of the knurled rim and slot.

Specification

Knurled Head Screw Specification

The range we manufacture and supply.

StandardsDIN 464 (high type, plain or slotted; includes the former DIN 465); DIN 653 (low type)

Size rangeM1–M10 (DIN 653 without M3.5)

ThreadMetric coarse; fine and inch threads to order

LengthsTo order; partial thread on the high type

KnurlStraight knurl; diamond knurl to order

DriveFingers; slotted head on the high type as an option

MaterialsSteel; A1 and A2 stainless steel; brass

FinishPlain, zinc plated or black steel; plain stainless; plain or nickel brass

CertificationMill certificate; EN 10204 3.1; PMI for stainless

PackingBoxes of 50 to 1000, kits to order

High vs low

DIN 464 High Type vs DIN 653 Low Type

Same knurled head, different height above the part.

M5 knurled thumb screws at the same scale, from DIN 653 and DIN 464. The collar of the high type lets the fingers grip under the knurl; the low type suits tight spaces.

Size	d_k knurl	DIN 653 low head height k	DIN 464 high total height h	Collar d_s DIN 464	Tap drill d − P	Clearance hole ISO 273 medium
M1	5.5	1.5	3.5	2.8	0.75	1.2
M1.2	6	1.5	4	3	0.95	1.4
M1.4	7	2	4.7	3.5	1.1	1.6
M1.6	7.5	2	5	3.8	1.25	1.8
M2	9	2	5.3	4.5	1.6	2.4
M2.5	11	2.5	6.5	5	2.05	2.9
M3	12	2.5	7.5	6	2.5	3.4
M3.5	14	–	8.5	7	2.9	3.9
M4	16	3.5	9.5	8	3.3	4.5
M5	20	4	11.5	10	4.2	5.5
M6	24	5	15	12	5	6.6
M8	30	6	18	16	6.75	9
M10	36	8	23	20	8.5	11

mm. Tap drill and ISO 273 medium clearance hole are standard practice for reference.

Dimensions

Knurled Thumb Screw Dimensions

DIN 464 heads from M1 to M10 at the same scale, knurled rim from above and profile with collar.

Size	P	d_k knurl dia. nom	k knurl height max	d_s collar dia. max	h head height nom	n slot nom	t slot depth min / max	b thread length
M1	0.25	5.5	1.5	2.8	3.5	0.3	0.7 / 0.9	3
M1.2	0.25	6	1.5	3	4	0.4	0.8 / 1	3.5
M1.4	0.3	7	2	3.5	4.7	0.4	0.9 / 1.15	4
M1.6	0.35	7.5	2	3.8	5	0.4	1 / 1.3	5
M2	0.4	9	2	4.5	5.3	0.5	1.1 / 1.4	6
M2.5	0.45	11	2.5	5	6.5	0.6	1.5 / 1.8	8
M3	0.5	12	2.5	6	7.5	0.8	1.8 / 2.2	9
M3.5	0.6	14	3	7	8.5	0.8	2 / 2.5	10
M4	0.7	16	3.5	8	9.5	1	2.2 / 2.7	12
M5	0.8	20	4	10	11.5	1.2	2.8 / 3.4	15
M6	1	24	5	12	15	1.6	3.5 / 4.3	18
M8	1.25	30	6	16	18	2	4.5 / 5.5	24
M10	1.5	36	8	20	23	2.5	6 / 7	30

DIN 464:2007 knurled thumb screws, high type, mm. The slot dimensions n and t apply to the slotted version (formerly DIN 465, withdrawn, same head).

Size	P	d_k knurl dia. nom	k head height max	d_s shank min	r under-head radius	a₁ thread run-out max
M1	0.25	5.5	1.5	–	0.5	0.75
M1.2	0.25	6	1.5	–	0.5	0.75
M1.4	0.3	7	2	–	0.5	0.9
M1.6	0.35	7.5	2	–	0.5	1.05
M2	0.4	9	2	1.86	0.5	1.2
M2.5	0.45	11	2.5	2.36	0.5	1.35
M3	0.5	12	2.5	2.86	0.5	1.5
M4	0.7	16	3.5	3.82	0.5	2.1
M5	0.8	20	4	4.82	1	2.4
M6	1	24	5	5.82	1	3
M8	1.25	30	6	7.78	2	3.75
M10	1.5	36	8	9.78	2	4.5

DIN 653:2006 knurled thumb screws, low type, mm. Same knurled head as DIN 464; no M3.5.

Tightening

How Tight Is Finger-Tight?

A knurled screw is meant to be done up by hand, and a hand on a small knurl delivers very little torque. The common estimate T = K × F × d (K about 0.2 for dry steel) shows what that means: 0.5 N·m on an M5 gives only about 500 N of clamp, a thread stress near 35 MPa.

That is ideal for covers, guides and adjustable stops, but not for joints that carry load or vibrate. There, use the slotted version and a screwdriver, add a locking feature, or choose a hex or socket screw tightened with a tool.

Need	Choose
Quick opening, light clamp	DIN 464 plain
Finger turning, tool to finish	DIN 464 slotted
Little room above the part	DIN 653 low type
Load or vibration	Hex or socket screw with a tool

Selection

Choosing a Knurled Thumb Screw

Room for fingers

Allow space round the knurl, and above it for the high type.

Length

Measured from under the head (under the collar on the high type).

Captive option

A reduced shank or a retaining washer keeps the screw in the panel.

Environment

Stainless or brass for wet, lab and outdoor use.

Tool backup

Pick the slotted DIN 464 if it may need a screwdriver.

Mating nuts

Pair with knurled nuts for tool-free assemblies.

Calculator

Knurled Screw Size & Clamp Force Estimator

Pick the size and type, then enter the hand torque to estimate the clamp force and thread stress.

Screw & torque

Size

Type

Hand torque, N·m

Our estimate: clamp force F = T ÷ (K × d) with K = 0.2; thread stress = F ÷ A_s (ISO 898-1 stress area). Real values vary widely with friction and finish. Dimensions from DIN 464 / DIN 653.

Result

500

N clamp force (est.)

35

MPa thread stress

Knurl d_k × k:20 × 4 mm

Height above part:11.5 mm (collar Ø 10)

Slot n × t max:1.2 × 3.4 mm

Tap drill:4.2 mm

Clearance hole:5.5 mm

Materials

Knurled Head Screw Materials & Finishes

Material	Finish	Best for
Steel	Plain, zinc plated, black	Fixtures, machines, indoor equipment
A1 stainless (303)	Plain	Turned screws, general stainless use
A2 stainless (304)	Plain, passivated	Laboratory, food and outdoor equipment
Brass	Plain, nickel plated	Instruments, electrical, decorative

Steel

Black or zinc

As in the photo.

1018 1022

Stainless A1

303

Free-machining for turned heads.

303

Stainless A2

304

Better corrosion resistance.

304 316

Brass

Free-cutting brass

Instruments and electrical.

C36000 C26000

Manufacturing

How Our Knurled Head Screws Are Made

1

Bar or wire

Steel, stainless or brass, certified by heat or lot.

2

Turning or heading

Head, collar and shank turned from bar or cold formed.

3

Knurling

Straight or diamond knurl rolled into the rim.

4

Slotting

Slot cut on slotted DIN 464 screws.

5

Threading

Threads rolled or cut to 6g.

6

Finishing

Zinc, black or nickel; stainless passivated.

Applications

Where Our Knurled Head Screws Are Used

Instrument covers

Panels that are opened for calibration and service.

Jigs & fixtures

Quick clamping and adjustable stops.

Laboratory equipment

Stainless screws on stands, clamps and housings.

Optics & cameras

Mounts and rails adjusted by hand.

Electronics racks

Front panels and inspection covers.

Machine guards

Access panels that are removed for cleaning.

Quality & testing

Knurled Head Screw Inspection & Certification

Check	Method	Applied to
Knurl diameter & height	Callipers: d_k, k	Every lot
Collar & head height	Callipers: d_s, h	High type
Knurl quality	Visual: even, burr-free	Every lot
Slot	Width n and depth t	Slotted lots
Thread	GO / NO-GO ring gauges	Every lot
Material	PMI / chemical analysis	Stainless and brass lots

Every shipment includes

Mill certificate with heat number
Dimensional report
Lot number on every box

On request

EN 10204 3.1 certificate
Salt spray test for plated lots
Screw and knurled nut kits

FAQ

Knurled Head Screw Questions, Answered

A knurled head screw, or knurled thumb screw, has a round head with a ridged (knurled) rim so it can be turned and tightened by hand without tools. DIN 464 covers the high type, with a collar under the knurled head, and DIN 653 the low type, with the knurled head directly on the shank, both from M1 to M10.

Both have the same knurled head, for example 20 mm across and 4 mm high for M5. DIN 464 adds a 10 mm collar under the head, so the head stands 11.5 mm high and the fingers can get under the knurl; DIN 653 is the low type, only 4 mm high, for tight spaces.

DIN 465, the slotted high-type knurled thumb screw, has been withdrawn. Its head dimensions are the same as DIN 464, for example 20 mm knurl, 10 mm collar and 11.5 mm total height for M5, and the current DIN 464 includes the slot width and depth, so slotted knurled screws are ordered to DIN 464.

Not very tight, which is the point of a thumb screw. As an estimate, torque = 0.2 × clamp force × diameter, so 0.5 N·m by hand on an M5 screw gives only about 500 N of clamp force. Where a joint must not loosen under vibration, use a slotted knurled screw tightened with a screwdriver, or a hex or socket screw.

The slot lets you turn the screw by hand for quick adjustment and then finish or release it with a screwdriver when it is tight, stuck or out of reach. For M5 the DIN 464 slot is 1.2 mm wide and 2.8 to 3.4 mm deep.

From the underside of the head to the end of the screw. On the high type the underside is the bottom of the collar, so the collar is not included in the length.

Wherever parts are adjusted, opened or changed often without tools: instrument and enclosure covers, fixtures and jigs, guards and inspection panels, camera and optical mounts, laboratory equipment and electronics racks.

Steel, plain, zinc plated or black finished like the screw in our photo; A1 and A2 stainless steel; and brass, plain or nickel plated. Stainless and brass suit laboratory, food and outdoor equipment.