Bolt and screw extractor size chart
A stripped bolt and a broken-off screw are two different problems, and the size chart for each tool answers a different question: for extractor sockets, which socket fits over which bolt head; for spiral screw extractors, which drill size opens the fastener for which extractor number. Both charts are below, in inch and metric as published, along with the set contents for the three tool families you will actually find in stores. Every row cites two or more named sources.
Three things to know before the charts.
- Sockets grip outside, spirals grip inside. A Bolt-Grip socket goes over a rounded head; a spiral extractor goes into a drilled hole in a fastener broken off flush [1] [5].
- The drill size is part of the extractor size. Irwin etches both on every Hanson spiral extractor: the tool and its pilot drill are a pair [5] [6].
- Extractors turn counterclockwise, and spiral flutes bite harder as resistance rises, so the stucker the fastener, the harder the tool grips [5] [1].
Which extractor for which job
The selection logic is the condition of the fastener, not its name. If the head exists but is rounded, rusted, or painted over, an extraction socket is the first move: Irwin's Bolt-Grip line is specified for exactly that, and it drives on a 3/8 in square drive ratchet or impact, or on hexagonal flats with a wrench or locking pliers [1] [2]. If the fastener is broken off flush or below the surface, there is nothing to grip outside, so you drill into the stub and use a spiral screw extractor, whose left-hand flutes dig in as you back it out [5] [6]. In between sits the multi-spline extractor, which Irwin lists at 1/8 to 7/8 in with a low profile for confined areas and more torque than other internal types, engaging without a deep hole [4] [14].
Spiral screw extractor chart (Irwin Hanson EX series)
The Hanson 534-series spirals are the default North American screw extractors, sold singly and in sets. The chart pairs each extractor with its drill size and the fastener sizes it removes, exactly as the listings publish them, in inch and metric where both are given.
| Extractor | Drill size | Removes (inch) | Removes (metric) | Screw sizes | Tap wrench | Sources |
|---|---|---|---|---|---|---|
| EX-1 | 5/64 in | 3/32 to 5/32 in | 2.5 to 4 mm | No. 3 to No. 6 | TR-88 | [5] [6] [7] |
| EX-2 | 7/64 in | 5/32 to 7/32 in | 4 to 6 mm | No. 6 to No. 12 | TR-88 | [5] [4] [8] |
| EX-3 | 5/32 in | 7/32 to 9/32 in | 6 to 8 mm | No. 12 | TR-88 | [5] [9] [10] |
| EX-4 | 1/4 in | 9/32 to 3/8 in | 8 to 10 mm | 1/8 in NPT fittings | TR-88 | [5] [4] [8] |
| EX-5 | 19/64 in | 3/8 to 5/8 in | 10 to 16 mm | 3/8 in NPT fittings | TR-98 | [5] [11] [12] |
| EX-6 | 13/32 in | 5/8 to 7/8 in | 16 to 22 mm | 3/8 in NPT fittings | TR-98 | [5] [13] [14] |
Row sources: [5] Toolbox Supply listings for the 53401 through 53406, [4] the Hanson Hand Tools brochure PDF and its 11117 10-piece set table, [6] Hardware World's 53401 listing and series drill-size selector, [7] KSC Direct's 53401 spec line, [8] Hechler Hardware's 53403 spec line, [9] ToolWeb's Hanson EX-3 spec block, [10] Smith Tool Supply's 53403 table, [11] Adam's Tar and Paint Tool 53405 spec, [12] Smith Tool Supply 53405, [13] AIH 53406 spec line, [14] Groves Industrial 53406. The drill sizes 5/64, 7/64, 5/32, 1/4, 19/64 also appear together in the Hanson 11117 brochure set contents, and 13/32 in MSC's 12-piece set listing. NPT fitting coverage varies by retailer listing for the larger sizes; where listings disagree on which NPT size goes with EX-5, we print Toolbox Supply's.
How to use a spiral extractor
The published method, identical across the Hanson listings: center-punch the broken fastener, drill a pilot hole with the extractor's specified bit size, insert the extractor, and turn counterclockwise [6] [9]. The flutes grip into the sides of the drilled hole and remove the broken part without damaging the threaded hole it sits in [9] [5]. Two practice points from the same sources: a left-hand drill bit is recommended for the pilot hole, because it sometimes spins the stub out on its own before the extractor is needed, and cutting oil on the pilot drill keeps the hole honest in hardened stubs. The drill sizes themselves are ordinary fractional sizes, so any index covers them; our tap and drill chart covers the decimal equivalents if your index is partial.
Bolt extractor socket chart (Irwin Bolt-Grip)
Bolt-Grip sockets size by the bolt head they grip, not by a drill hole. The base set and the expansion set together run from 5/16 to 3/4 in, and every socket carries a 3/8 in square drive plus hexagonal flats for a wrench or pliers.
| Socket size | Also marked | Set | Sources |
|---|---|---|---|
| 3/8 in | - | Base set 394001 | [2] [3] [15] |
| 7/16 in | 11 mm | Base set 394001 | [2] [3] [15] |
| 1/2 in | - | Base set 394001 | [2] [3] [15] |
| 9/16 in | 14 mm | Base set 394001 | [2] [3] [15] |
| 5/8 in | 16 mm | Base set 394001 | [2] [3] [15] |
| 5/16 in | 8 mm | Expansion set 394002 | [16] [17] |
| 10 mm | - | Expansion set 394002 | [16] [17] |
| 13 mm | - | Expansion set 394002 | [16] [17] |
| 11/16 in | - | Expansion set 394002 | [16] [17] |
| 3/4 in | 19 mm | Expansion set 394002 | [16] [17] |
Row sources: [2] the Irwin Bolt-Grip technical datasheet via Cromwell, [3] True Value's 394001 set listing, [15] JB Tools' 394001 set contents, [16] Beach Audio's 394002 listing, [17] MPR Tools' 394002 contents. The base set's case is built to hold the expansion set alongside it, so the combined 10 sockets live in one box [15] [17].
Fit guidance is one line: pick the socket that matches the nominal head size, seat it fully, and drive it with a 3/8 in ratchet, breaker bar, or impact; the reverse spiral flutes bite down as torque rises [2] [1]. On a head that has swollen with rust, one size down from nominal is the practical choice, which is why the sets pack sizes this tightly.
GearWrench Bolt Biter extractor sizes
The Bolt Biter family is the main alternative, and its screw extractor chart runs on extractor numbers 1 to 5, each with its own extraction drill bit. The sizing below is GearWrench's own flyer, confirmed by two independent retailers' set listings.
| Extractor size | Drill bit | Screw size (SAE) | Screw size (metric) | Sources |
|---|---|---|---|---|
| 1 | 1/8 in | 1/4 in and smaller | M5 to M6 | [18] [19] [20] |
| 2 | 3/16 in | 5/16 to 3/8 in | M8 to M10 | [18] [19] [20] |
| 3 | 9/32 in | 7/16 to 1/2 in | M12 to M14 | [18] [19] [20] |
| 4 | 3/8 in | 9/16 to 5/8 in | M14 to M16 | [18] [19] [20] |
| 5 | 7/16 in | 3/4 in | M18 to M20 | [18] [19] [20] |
Row sources: [18] the GearWrench Bolt Biter flyer PDF's sizing table, [19] BC Fasteners' 84786 set listing, [20] Grey Wolf Safety's 84786 spec block. The 10-piece set 84786 is five extractors plus the five matching drill bits in a molded case [18] [19].
Bolt Biter's socket side sizes like Bolt-Grip does, by fastener size. The 7-piece SAE socket set 83911 runs 1/4, 5/16, 3/8, 7/16, and 1/2 in on 1/4 and 3/8 in drives [18] [21], and the 28-piece impact set 84784 mixes SAE and metric from 1/4 in and 6 mm up to 3/4 in and 19 mm [21] [18]. GearWrench's design claim is the reverse of Irwin's: Bolt Biter sockets grip the fastener instead of cutting into it, which the company says makes them last ten times longer under an impact gun and preserves the fastener [18] [21]. That is a manufacturer claim, not something we tested.
Which extractor for which bolt, in one list
- Machine screws No. 3 to No. 6 (2.5 to 4 mm): spiral EX-1 on a 5/64 in pilot hole [5] [6].
- 1/4 in and smaller, or M5 to M6: Bolt Biter size 1 with its 1/8 in bit [18] [19].
- 1/4 to 3/8 in bolts, broken off: EX-3 or EX-4 on 5/32 or 1/4 in holes [5] [9].
- 3/8 to 5/8 in bolts, rounded head: Bolt-Grip base set sockets 3/8 through 5/8 in [2] [3].
- 3/8 to 5/8 in bolts, broken off: EX-5 on a 19/64 in hole [5] [11].
- 5/8 to 3/4 in and up: EX-6 on a 13/32 in hole, or the Bolt-Grip expansion sockets 11/16 and 3/4 in [5] [16].
- Lug nuts: dedicated lug extraction sockets; GearWrench sells a Bolt Biter lug nut line separate from these charts [18].
What the sets actually contain
Three sets cover most purchases. Irwin's 11117 is 10 pieces in a metal index: the five spiral extractors EX-1 to EX-5 with their five matching left-hand cobalt drill bits [4] [22]. The Bolt-Grip base set 394001 is the five most common sockets, 3/8 to 5/8 in, in a case with empty slots for the 394002 expansion set [3] [15]. GearWrench's 84786 is the five Bolt Biter extractors with their five bits [18] [19]. A complete kit for a working shop is one socket set plus one spiral set; Irwin also sells a 48-piece master set that adds the multi-spline series if you want everything in one index [4] [14].
The extraction drill bits deserve their own note: they are left-hand twist bits, which turn reverse of a normal drill and can catch the stub and spin it out during the pilot-hole step. Irwin pairs cobalt ones with the Hanson extractors in the sets [4] [22], and the drill side of why cobalt matters in hardened stubs is on our drill bit coatings page. For the drilling speeds those pilots want in steel, the drill speed chart has RPM by diameter; for the hole sizes screws want when they are not broken, the pilot hole chart and tap drill chart are the references. Broken bolts in wood, rather than metal, usually want a different bit approach entirely.
Related guides
Also on this site: the pilot hole chart for drilling holes screws survive, the tap and drill chart for decimal equivalents of these extractor drill sizes, drill bit coatings compared for the cobalt question on extraction drill bits, drill bits by material, the drill speed chart for pilot-hole RPM, and step drill bit sizes for opening the hole after a fastener is out.
Sources
- IRWIN Tools, BOLT-GRIP bolt extractors product page (reverse spiral flutes, high carbon steel, 3/8 in square drive, hex flats): irwintools.com
- Irwin 10504634 Bolt-Grip technical datasheet via Cromwell (base set contents 3/8, 7/16/11mm, 1/2, 9/16/14mm, 5/8/16mm): cromwell.co.uk
- True Value, Irwin BOLT-GRIP 5-piece bolt extractor set listing (same five sizes, drive options, metric and standard fit): truevalue.com
- Hanson Hand Tools brochure PDF (extractor families overview, multi-spline 1/8 to 7/8 in, 11117 set contents with drill sizes, bolt extractor range 1/4 to 1 in): toolsid.com
- Toolbox Supply, Hanson spiral flute screw extractor listings 53401 to 53406 (drill size, fastener range, tap wrench per size): toolboxsupply.com
- Hardware World, Irwin Hanson EX-1 listing with series drill-size selector (5/64, 7/64, 5/32, 1/4, 19/64, 13/32 in): hardwareworld.com
- KSC Direct, Irwin Hanson 53401 spec line (EX-1, 5/64 in drill, 3/32 to 5/32 in, 2.5 to 4 mm, No. 3 to 6): kscdirect.com
- Hechler Hardware, Irwin Hanson 53403 listing (EX-3, 7/32 to 9/32 in, 6 to 8 mm, No. 12, 5/32 in drill): hechlerhardware.com
- ToolWeb, Hanson EX-3 spiral screw extractor spec block (TR-88, 5/32 in drill, method of use): toolweb.com
- Smith Tool Supply, Irwin Hanson 53403 table (drill bit, tap wrench, fastener range): smithtoolsupply.com
- Adam's Tar and Paint Tool, Irwin 53405 listing (19/64 in drill, TR-98, 3/8 to 5/8 in, 10 to 16 mm): adamstarpntool.com
- Smith Tool Supply, Irwin Hanson 53405 table (19/64 in drill, 3/8 to 5/8 in range): smithtoolsupply.com
- AIH, Irwin Hanson 53406 spec line (EX-6, 13/32 in drill, 5/8 to 7/8 in, 16 to 22 mm): aih.com
- Groves Industrial, Irwin Hanson 53406 EX-6 listing (13/32 in drill, screw size range): grovesindustrial.com
- JB Tools, Irwin 5-piece Hanson Bolt-Grip base set 394001 (contents, use, expandable case): jbtools.com
- Beach Audio, Hanson 394002 5-piece expansion set (8mm/5/16, 10mm, 13mm, 11/16, 19mm/3/4): beachaudio.com
- MPR Tools, IRWIN bolt extractor expansion set 394002 (same sizes, drive spec): mprtools.com
- GearWrench, Bolt Biter extraction flyer PDF (screw extractor sizing table, socket set sizes, grip-not-cut claims, lug nut line): gearwrench.com
- BC Fasteners, GearWrench 84786 Bolt Biter screw extractor set listing (extractor sizes, drill bits, case): bcfasteners.com
- Grey Wolf Safety, Bolt Biter screw extractor set 10 pc spec block (5 extractors, 5 drill bits): greywolfsafety.com
- The Home Depot, GearWrench 28-piece Bolt Biter impact extraction socket set 84784 (SAE and metric size run, grip claim): homedepot.com
- MSC Industrial Supply, Irwin Hanson 10-piece spiral extractor and drill set 11117 (extractors with corresponding left-hand cobalt bits): mscdirect.com