Fillister Head Screws Manufacturer in India

Overview

Fillister Machine Screws (ASME B18.6.3): Manufacturer & Distributor

A fillister head is small across and tall: cylindrical sides, a slightly domed top and a deep slot or recess. It drops into counterbores and tight spaces where a pan head will not fit.

Exotic Alloy manufactures fillister head screws in Mumbai, India, for instrument, electrical, machinery and equipment builders. We stock across India and supply Colombia, Latin America, North America, the Gulf and Europe. Heads are cold headed and threads are rolled to UNC and UNF.

Three versions

The slotted head (ASME B18.6.3 Table 21), the Phillips head with the same head dimensions (recess per Table 22), and the slotted drilled head with a cross hole for lock wire (Table 23). The metric relative is the cheese head screw.

ASME B18.6.3 No. 0 to 3/4″ Slotted & Phillips Drilled heads UNC & UNF

Fillister head screw at a glance

Head: Cylindrical, domed top; A ≈ 1.6–1.66 D up to 3/8″
Standard: ASME B18.6.3 Tables 21, 22, 23
Drive: Slot or Phillips No. 0–4
Length: From under the head
Special: Drilled head for lock wire
Related: Cheese, pan, round heads

ASME No. 10-24 × 1/2″ slotted fillister head screw, drawn to scale at maximum dimensions. Dome and thread shown schematically; top views of slotted and Phillips heads.

Specification

Fillister Head Screw Specification

The range we manufacture and supply.

StandardASME B18.6.3-2013: Table 21 slotted, Table 22 recess, Table 23 slotted drilled

Size rangeNo. 0 to 3/4″ (micro sizes 0000–00 and drilled No. 2–3/8″ to order)

ThreadUNC and UNF, class 2A, rolled

LengthsTo order, measured from under the head

DriveSlotted; Phillips (Type I) No. 0–4; slotted and drilled

Drilled headCross hole 0.031–0.070″ for lock wire, at right angles to the slot

Materials18-8 (304) and 316 stainless; low-carbon steel; brass

FinishPlain or passivated stainless; zinc plated or black oxide steel; plain or nickel brass

CertificationMill certificate; EN 10204 3.1; PMI for stainless

PackingBoxes of 100 to 5,000, bulk cartons, kits

Types & comparison

Slotted, Phillips & Drilled Fillister vs Pan & Round

Narrower and taller than pan and round heads, with a deeper slot.

No. 10 heads at the same scale. The three fillister versions share one head; the pan and round heads are wider and the pan head much lower.

Size	Fillister A × O max	Pan, slotted A × H max	Round A × H max	Fillister slot depth T max	Pan slot depth T max	Tap drill 75 % thread
No. 2-56	.140 × .083	.167 × .053	.162 × .069	.037	.031	#50 (.0700)
No. 4-40	.183 × .107	.219 × .068	.211 × .086	.048	.040	#43 (.0890)
No. 6-32	.226 × .132	.270 × .082	.260 × .103	.060	.050	#36 (.1065)
No. 8-32	.270 × .156	.322 × .096	.309 × .120	.071	.058	#29 (.1360)
No. 10-24	.313 × .180	.373 × .110	.359 × .137	.083	.068	#25 (.1495)
No. 12-24	.357 × .205	.425 × .125	.408 × .153	.094	.077	#16 (.1770)
1/4″-20	.414 × .237	.492 × .144	.472 × .175	.109	.087	#7 (.2010)
5/16″-18	.518 × .295	.615 × .178	.590 × .216	.137	.106	F (.2570)
3/8″-16	.622 × .355	.740 × .212	.708 × .256	.164	.124	5/16″ (.3125)
1/2″-13	.750 × .412	.987 × .281	.813 × .355	.190	.161	27/64″ (.4219)

Inch, ASME B18.6.3 maximum values: fillister Table 21, slotted pan Table 17, round head (2002 edition). Tap drills give about 75 % thread (our check).

Dimensions

Fillister Head Screw Dimensions (ASME B18.6.3)

Slotted fillister heads from No. 0 to 3/4″ at the same scale. Up to 3/8″ the head is about 1.6 to 1.66 times the screw diameter; from 7/16″ it drops to 1.33 to 1.5 times.

Size	Basic dia. in	TPI UNC	A head dia. max / min	H side height max / min	O total height max / min	J slot width max / min	T slot depth max / min	Phillips driver
No. 0000	.021	–	.038 / .032	.019 / .011	.025 / .015	.008 / .004	.012 / .006	–
No. 000	.034	–	.059 / .053	.029 / .021	.035 / .027	.012 / .006	.017 / .011	–
No. 00	.047	–	.082 / .072	.037 / .028	.047 / .039	.017 / .010	.022 / .015	–
No. 0	.060	80 UNF	.096 / .083	.043 / .038	.055 / .047	.023 / .016	.025 / .015	No. 0
No. 1	.073	64	.118 / .104	.053 / .045	.066 / .058	.026 / .019	.031 / .020	–
No. 2	.086	56	.140 / .124	.062 / .053	.083 / .066	.031 / .023	.037 / .025	No. 1
No. 3	.099	48	.161 / .145	.070 / .061	.095 / .077	.035 / .027	.043 / .030	No. 1
No. 4	.112	40	.183 / .166	.079 / .069	.107 / .088	.039 / .031	.048 / .035	No. 1
No. 5	.125	40	.205 / .187	.088 / .078	.120 / .100	.043 / .035	.054 / .040	No. 2
No. 6	.138	32	.226 / .208	.096 / .086	.132 / .111	.048 / .039	.060 / .045	No. 2
No. 8	.164	32	.270 / .250	.113 / .102	.156 / .133	.054 / .045	.071 / .054	No. 2
No. 10	.190	24	.313 / .292	.130 / .118	.180 / .156	.060 / .050	.083 / .064	No. 2
No. 12	.216	24	.357 / .334	.148 / .134	.205 / .178	.067 / .056	.094 / .074	No. 3
1/4″	.250	20	.414 / .389	.170 / .155	.237 / .207	.075 / .064	.109 / .087	No. 3
5/16″	.312	18	.518 / .490	.211 / .194	.295 / .262	.084 / .072	.137 / .110	–
3/8″	.375	16	.622 / .590	.253 / .233	.355 / .315	.094 / .081	.164 / .133	No. 4
7/16″	.438	14	.625 / .589	.265 / .242	.368 / .321	.094 / .081	.170 / .135	–
1/2″	.500	13	.750 / .710	.297 / .273	.412 / .362	.106 / .091	.190 / .151	–
9/16″	.562	12	.812 / .768	.336 / .308	.466 / .410	.118 / .102	.214 / .172	–
5/8″	.625	11	.875 / .827	.375 / .345	.521 / .461	.133 / .116	.240 / .193	–
3/4″	.750	10	1.000 / .945	.441 / .406	.612 / .542	.149 / .131	.281 / .226	–

ASME B18.6.3-2013 Table 21, inch; Phillips heads use the same head dimensions. Phillips driver sizes are shown where two sources agree; for 5/16″ ask us. No. 0 is threaded 0-80 UNF only; 0000 to 00 have special threads.

Size	A head dia. max / min	H side height max / min	O total height max / min	J slot width max / min	T slot depth max / min	E hole location basic	F hole dia. basic (drill)
No. 2	.140 / .124	.062 / .055	.083 / .070	.031 / .023	.030 / .022	.026	.031 (#68)
No. 3	.161 / .145	.070 / .064	.095 / .082	.035 / .027	.034 / .026	.030	.037 (#63)
No. 4	.183 / .166	.079 / .072	.107 / .094	.039 / .031	.038 / .030	.035	.037 (#63)
No. 5	.205 / .187	.088 / .081	.120 / .106	.043 / .035	.042 / .033	.038	.046 (#56)
No. 6	.226 / .208	.096 / .089	.132 / .118	.048 / .039	.045 / .035	.043	.046 (#56)
No. 8	.270 / .250	.113 / .106	.156 / .141	.054 / .045	.065 / .054	.043	.046 (#56)
No. 10	.313 / .292	.130 / .123	.180 / .165	.060 / .050	.075 / .064	.043	.046 (#56)
No. 12	.357 / .334	.148 / .139	.205 / .188	.067 / .056	.087 / .074	.053	.046 (#56)
1/4″	.414 / .389	.170 / .161	.237 / .219	.075 / .064	.102 / .087	.062	.062 (1/16″)
5/16″	.518 / .490	.211 / .201	.295 / .276	.084 / .072	.130 / .110	.078	.070 (#50)
3/8″	.622 / .590	.253 / .242	.355 / .333	.094 / .081	.154 / .134	.094	.070 (#50)

ASME B18.6.3-2013 Table 23, inch. Same head diameter and side height as Table 21, but a shallower slot and a higher minimum head height. The hole is drilled roughly at right angles to the slot, may break into the slot bottom and must be free of burrs.

Drilled heads

Drilled Fillister Heads & Lock Wire

A cross hole through the head takes lock (safety) wire. The wire is routed so that its pull turns each screw clockwise, the tightening direction, so the screws cannot back off.

Where vibration could loosen a screw and a loose screw would be dangerous or costly, drilled fillister heads are tied together with stainless lock wire, or sealed with wire and a lead or plastic seal against tampering.

The holes are standard drill sizes, from 0.031″ (#68) on No. 2 to 0.070″ (#50) on 3/8″. Choose a wire that passes freely through the hole, and follow your industry’s wiring practice.

Need	Choose
Vibration, safety-critical joint	Slotted drilled fillister + lock wire
Tamper evidence	Drilled fillister + seal wire
Power driving	Phillips fillister
Wider bearing face	Pan head
Metric design	Cheese head

Metric equivalents

Fillister vs Metric Cheese Head (ISO 1207)

Converting a design between inch and metric? The nearest metric head is the ISO 1207 cheese head. It has a flat top and is lower, so a counterbore sized for one is not always right for the other. The threads differ, so the screws are never interchangeable.

Inch fillister	A × O in, max	A × O mm	Nearest metric ISO 1207 cheese	d_k × k mm, max	Head width fillister vs cheese
No. 2	.140 × .083	3.56 × 2.11	M2	3.8 × 1.4	-0.2 mm
No. 4	.183 × .107	4.65 × 2.72	M3	5.5 × 2	-0.9 mm
No. 6	.226 × .132	5.74 × 3.35	M3.5	6 × 2.4	-0.3 mm
No. 8	.270 × .156	6.86 × 3.96	M4	7 × 2.6	-0.1 mm
No. 10	.313 × .180	7.95 × 4.57	M5	8.5 × 3.3	-0.5 mm
1/4″	.414 × .237	10.52 × 6.02	M6	10 × 3.9	+0.5 mm
5/16″	.518 × .295	13.16 × 7.49	M8	13 × 5	+0.2 mm
3/8″	.622 × .355	15.80 × 9.02	M10	16 × 6	-0.2 mm

ASME B18.6.3 Table 21 and ISO 1207 maximum head sizes; pairing by nearest thread diameter and conversion are our own.

Calculator

Fillister Counterbore & Tap Drill Calculator

Pick the size, set the clearance and extra depth, and get the counterbore, tap drill and head data in inch and mm.

Screw & counterbore

Size (UNC)

Clearance per side, in

Extra depth, in

Our rule of thumb: counterbore diameter = A max + 2 × clearance; depth for a fully sunk head = O max + extra depth; with only the cylindrical side sunk (dome proud) = H max + extra depth. Head data from ASME B18.6.3 Table 21 (drilled heads Table 23); tap drills give about 75 % thread. Check against your own design rules.

Result

.345

in counterbore Ø (8.76 mm)

.190

in deep (4.83 mm)

Head A × H × O:.313 × .130 × .180″

Depth, dome proud:.140″ (3.56 mm)

Slot J × T / Phillips:.060 × .083″ / No. 2

Tap drill:#25 (.1495″), 75 %

Drilled head hole:.046″ (#56)

Nearest metric:M5 cheese head

Materials

Fillister Head Screw Materials & Finishes

Material	Finish	Best for
18-8 stainless (304)	Plain, passivated	Instruments, food, outdoor and general use
316 stainless	Plain, passivated	Marine, chemical and coastal plant
Low-carbon steel	Plain, zinc plated, black oxide	Machinery, electrical and general assembly
Brass	Plain, nickel plated	Electrical terminals, instruments, non-magnetic

ASME B18.6.3: unless otherwise specified, steel machine screws are non-heat-treated low-carbon steel such as 1006 to 1022, Rockwell B69 to B100.

18-8 stainless

304

The everyday choice.

304

316 stainless

Molybdenum

Chlorides and marine air.

316

Steel

1006–1022

Zinc or black oxide.

1018 1022

Brass

Plain or nickel

Conductive, non-magnetic.

C26000 C36000

Manufacturing

How Our Fillister Head Screws Are Made

1

Wire

Cold heading quality wire, certified by heat.

2

Cold heading

Tall head and Phillips recess formed in a two-blow header.

3

Slotting & drilling

Slots cut; cross holes drilled and deburred on drilled heads.

4

Thread rolling

UNC or UNF threads rolled to class 2A.

5

Finishing

Passivating, zinc, black oxide or nickel.

6

Inspection & packing

Gauged, boxed and labelled by lot.

Applications

Where Our Fillister Head Screws Are Used

Instruments

Counterbored housings, gauges and meters.

Electrical

Terminal blocks, switches and relays.

Machinery

Covers, guards and tooling in tight spaces.

Lock-wired joints

Drilled heads on vibrating equipment.

Sealed meters

Wire and seal against tampering.

Hardware & instruments

Classic slotted heads on visible parts.

Quality & testing

Fillister Head Screw Inspection & Certification

Check	Method	Applied to
Head A, H, O	Micrometer / callipers	Every lot
Slot J, T	Slot gauges	Slotted lots
Phillips recess	Penetration gauge	Phillips lots
Cross hole	Pin gauge, burr check	Drilled lots
Thread	2A 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
First article inspection report

FAQ

Fillister Head Screw Questions, Answered

A machine screw with a small-diameter, tall head: cylindrical sides and a slightly domed top. Under ASME B18.6.3 a No. 10 fillister head is 0.292 to 0.313 in across and 0.156 to 0.180 in high overall, against 0.357 to 0.373 in across for a No. 10 pan head.

Same idea in two systems. The fillister is the inch head of ASME B18.6.3, with a domed top; the cheese head is the metric ISO 1207 head (formerly DIN 84) with a flat top. A No. 10 fillister head is 0.313 in (7.95 mm) across and 0.180 in (4.57 mm) high; an M5 cheese head is 8.5 mm across and 3.3 mm high.

The tall head carries a deep slot, up to 0.083 in on a No. 10 against 0.068 in on a No. 10 pan head, which gives the screwdriver a good grip, and its small diameter fits counterbores and narrow spaces.

A slotted fillister head with a small cross hole through the head for lock (safety) wire. ASME B18.6.3 Table 23 lists them from No. 2 to 3/8 in; on a No. 10 the hole is 0.046 in (a No. 56 drill), drilled roughly at right angles to the slot. The wire is routed so its tension turns each screw in the tightening direction.

No. 0 for No. 0 screws, No. 1 for No. 2 to No. 4, No. 2 for No. 5 to No. 10, No. 3 for No. 12 and 1/4 in, and No. 4 for 3/8 in. Cross recessed fillister heads have the same head dimensions as slotted ones.

From under the head to the end of the screw. The head is not included, unlike a flat countersunk head, which is measured overall.

Our rule of thumb is the maximum head diameter plus a clearance each side, and the maximum total head height plus a little extra depth for a flush or sunk head. For a No. 10 with 0.016 in clearance per side that is 0.345 in (8.8 mm) across and at least 0.180 in deep. The calculator on this page works it out for every size.

18-8 (304) and 316 stainless steel; low-carbon steel, plain, zinc plated or black oxide; and brass. Unless otherwise specified, ASME B18.6.3 steel machine screws are low-carbon steel such as 1006 to 1022, Rockwell B69 to B100.