Self-feed drill bit sizes: diameter x length chart
A self-feed bit is the plumbers' and electricians' wood borer: a short, fat bit with a threaded lead screw that pulls itself into the framing, twin spurs that score the hole wall, and an inside cutting plane that shaves the radius clean, so the operator steers rather than pushes [1][4][5]. The category exists for one job: repeated holes of 1 in and up through studs and joists for pipe and conduit [1][4]. This chart prints the size matrix from five manufacturer tables, Milwaukee, Bosch, IRWIN, Makita and DeWalt, with part numbers, the 7/16 in hex shank rule that holds the whole category together, and the maker-published RPM figures, which are rarer here than in any other bit family. For the long single-flute bits that bore deep timber, see our ship auger bit sizes page; the two categories are siblings, not rivals.
The size grid at a glance
Four specs define a self-feed bit, and the makers align on all four more closely than in any other wood-boring family [1][3][5][7]:
| Spec | Standard values | Notes |
|---|---|---|
| Cutting diameter | 1 to 4-5/8 in | steps of 1/8 and 1/4 in, plus the 2-9/16 and 3-5/8 pipe sizes [1][5][7] |
| Overall length | 5 to 6 in | Bosch prints 5 in total with 3 in working length across its whole line; IRWIN prints 5 in; Milwaukee runs 6 in in the dealer feeds [5][7][9] |
| Shank | 7/16 in hex | category-wide; Milwaukee 3 in and larger switch to three milled flats with a replaceable arbor [1][5] |
| Lead screw | replaceable, coarse thread | spare screws and set screws sold by every maker; Milwaukee ships two screws per bit [1][2] |
Two honest reading notes before the tables. First, overall length is the sloppiest spec in this category: several Milwaukee distributor feeds print 3-5/8 in or 4-1/2 in OAL values that other feeds and the physical class contradict, and this page discloses each divergence in the row rather than picking a winner. Second, the diameter ladder is not continuous below 1 in: no major maker sells a self-feed bit smaller than 1 in, so 3/4 in cable holes belong to spade bits or augers.
Main matrix: diameter x length x shank x part number
Every row is anchored on at least one first-party manufacturer table, and most carry two independent surfaces (a second maker table or independent dealer spec sheets). Where a value rests on conflicting feeds, the Notes column says so [1][3][5][7][12].
| Diameter (in) | For pipe (in) | Overall length | Shank | Milwaukee | Bosch | IRWIN Max | Makita | DeWalt | Sources |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1/2 | 5 in | 7/16 hex | 48-25-1002 | not listed | 3046004 | D-29935 | DW1630 | [1][7][12][14][15] |
| 1-1/8 | 3/4 | 5 in | 7/16 hex | 48-25-1122 | SF1121 | 3046005 | D-29957 | DW1631 | [1][5][7][12][19] |
| 1-1/4 | 1 (loose) | 5 in | 7/16 hex | 48-25-1252 | SF1251 | 3046006 | D-29963 | DW1632 | [1][5][7][12][19] |
| 1-3/8 | 1 | 6 in (Milwaukee dealer feeds) / 5 in (Bosch, IRWIN) | 7/16 hex | 48-25-1372 | SF1371 | 3046007 | D-29979 | DW1633 | [1][5][7][9][12] |
| 1-1/2 | 1 | 6 in (Milwaukee feeds) / 5 in (Bosch, IRWIN) | 7/16 hex | 48-25-1502 | SF1501 | 3046008 | D-29985 | DW1634 | [1][5][7][12][19] |
| 1-3/4 | 1-1/4 to 1-1/2 | 6 in (Milwaukee feeds) / 5 in (Bosch, IRWIN Supreme 6 in) | 7/16 hex | 48-25-1752 | SF1751 | 3046009; Supreme IWAX2006 | D-29991 | DW1635 | [1][5][7][8][12] |
| 2 | 1-1/2 | 6 in | 7/16 hex | 48-25-2002 | SF2001 | 3046010; Supreme IWAX2007 | D-30003 | DW1636 | [1][5][7][8][10][12] |
| 2-1/8 | 1-1/2 | 6 in (Milwaukee merrimac feed) / 4-1/2 in (ballard, firstsupply feeds) / 5 in (Bosch, IRWIN) | 7/16 hex | 48-25-2122 | SF2121 | 3046011; Supreme IWAX2008 | D-30019 | DW1637 | [5][7][8][9][10] |
| 2-1/4 | 2 (tight) | 5 in | 7/16 hex | 48-25-2252 | SF2251 | 3046012 | D-30025 | not listed | [1][5][7][12] |
| 2-9/16 | 2 | 6 in (dkhardware feed) / 3-5/8 in (several distributor feeds, flagged) / 5 in (Bosch, IRWIN) | 7/16 hex | 48-25-2562 | SF2561 | 3046013; Supreme IWAX2009 | D-30031 | DW1639 | [5][7][8][9][20][21] |
| 3 | 2-1/2 | 5 in | 7/16 hex (Bosch 3-flat; Milwaukee 3-flat + replaceable arbor) | 48-25-3001 | SF3001 | 3046014 | D-30047 | DW1640 | [1][5][7][12][19] |
| 3-5/8 | 3 | 5 in | same as 3 in class | 48-25-3621 | SF3621 | 3046015 | D-74414 (65 x 127 mm UK) | DW1641 | [1][5][7][13][18] |
| 4-1/8 | 3 PVC w/ coupling | 5 in class | same as 3 in class | 48-25-4125 | not listed | not listed | not listed | not listed | [1][2] |
| 4-5/8 | 4 | 5 in class | same as 3 in class | 48-25-4621 | SF4621 | 3046016 | D-74429 (117 x 127 mm UK) | DW1642 | [1][5][7][13][19] |
Reading the matrix honestly. The Milwaukee 4-1/8 in size (48-25-4125) is catalog-attested only: it appears in Milwaukee's own PTA table and spec sheet, but no second manufacturer lists it and no dealer spec surface with an OAL was found, so treat it as a specialty order [1][2]. The Milwaukee 3-5/8 and 4-5/8 rows carry their OAL only in the class sense (the 5 in Bosch/IRWIN rows); Milwaukee's own surfaces do not print an OAL for the big sizes. The pipe-size column is Milwaukee's own published mapping, which is the whole point of the ladder: 1 in bit for 1/2 in pipe, 2-9/16 for 2 in pipe, and so on [1].
The shank rule, and the one wrinkle
Print one number on the shop wall: 7/16 in hex. Milwaukee's spec sheet prints it for the 1 through 2-9/16 ladder [1], Bosch's table prints it for its whole SF line [5], IRWIN prints 7/16 in quick-change on both Max and Supreme lines [7][8], Makita's catalog prints 7/16 in heavy-duty shank [12], and DeWalt's product pages specify a 7/16 in ball-groove hex quick-change shank [19]. That means every self-feed bit on this page fits a 1/2 in chuck, and clicks into the same quick-change holders right-angle drills use.
The wrinkle sits at the big end and in one maker's wording. Milwaukee's 3 in and larger bits abandon the plain hex for a shank with three milled flats and a replaceable arbor (48-07-0201), with a different feed screw and a 5/32 in hex key instead of the 1/8 in key the smaller bits use [1]. And Makita's USA product pages describe their self-feed shank as "heavy duty 1/2 in with three milled flats" while the Makita reference catalog prints "7/16 in heavy-duty shank" for the same family; both are Makita's own statements, printed a decade apart, and the divergence is disclosed here rather than resolved [4][12].
Speed: what the makers actually publish
This is the part most charts invent, so here is exactly what exists. Milwaukee, Bosch, IRWIN and DeWalt print no RPM guidance for self-feed bits on any product surface pulled for this chart. The only manufacturer-published per-diameter speeds in the category are Makita's UK spec sheets, and they are simple: 500 rpm in wood across the 1 in through 2-1/4 in sizes (25 to 57 mm), and 300 rpm for the 4-5/8 in (117 mm) bit [13]. No formula is offered or implied by any maker, and this page prints none.
The tool makers fill in the picture indirectly: Makita rates its standard right-angle stud drills for 2-9/16 in self-feed bits, its big right-angle machines for 4-5/8 in, and its drill manuals put self-feed capacities in the low-speed gear (the DA4031 manual lists a 300 rpm low range alongside its 4-5/8 in self-feed capacity) [6]. That is class guidance from the tool side, not a bit spec, and it is labeled as such. For the general RPM-by-diameter logic, see our drill speed chart and drill press speed chart pages.
Self-feed vs spade vs hole saw vs Forstner
The four wood-boring families answer four different questions, and the screw tip is what separates a self-feed bit from all of them [4][7]:
| Question | Winner | Why | Sources |
|---|---|---|---|
| Repeated 1 in+ holes through studs for pipe | Self-feed | screw tip pulls the bit, spurs score the wall, clean hole with no pushing | [1][4] |
| Fast rough holes in thin stock, lowest cost | Spade bit | cheaper, faster to 1-1/2 in, but needs operator pressure and tears the exit | [4][7] |
| Flat-bottomed blind holes, hinge cups | Forstner | rim-guided flat bottom; a self-feed bit cannot drill a partial-depth hole cleanly | [7] |
| Holes past 4-5/8 in, or non-wood material | Hole saw | annular cut scales where a solid self-feed head cannot | [7] |
| Deep holes through multiple members, poles | Ship auger | long flute clears chips from holes a 6 in self-feed body cannot reach | [4] |
One note the spec sheets do not print but the geometry forces: there is no fish hole in a self-feed bit. The wire-pulling hole through the tip belongs to bell hanger bits and flexible installer bits; every self-feed surface surveyed here is a solid screw tip, and pulling wire is not what the category is built for. The full family comparison lives on our wood boring bits compared page.
Extensions, kits, and replaceable parts
Because the shank standard is shared, the extension market is shared too: Milwaukee's 7/16 in hex extensions run 5-1/2, 12, 18 and 24 in (48-28-4001 to 48-28-4016), Bosch sells 6 and 12 in versions (EX1006, EX1012), Makita's run 5-1/2, 12 and 18 in (D-35645, D-35651, D-35639), and DeWalt's kit extension is 5-1/2 in (DW1646) [1][5][13][19]. Every kit follows the same logic: Milwaukee's 4-piece contractor kit pairs the 1-3/8, 1-1/2, 2-1/8 and 2-9/16 sizes with an extension and a 5-1/2 in one-piece shank and coupling [2], and DeWalt's multipacks bundle the same staple sizes plus a spare-parts pack (DW1650) [19].
What wears out is the lead screw, not the body. Milwaukee ships two removable feed screws per bit and sells coarse and regular-thread replacements plus set screws [1][2]; IRWIN sells replacement tip packs in three diameter bands (1792762 for 1 to 1-3/8, 1792763 for 1-1/2 to 2-9/16, 1792764 for 3 to 4-5/8) [7]; and Milwaukee's SwitchBlade line takes the idea further with a fully replaceable cutting blade in 1-3/8 through 2-9/16 in (48-25-5120 to 48-25-5150, about 5 in OAL per the dealer listings), sold as a 10-piece plumber's set [11][16][17]. A dull self-feed bit is usually a 10 dollar screw, not a 50 dollar bit.
Buying by size: the pipe logic
The diameter ladder is not arbitrary; it is the pipe schedule in disguise, and Milwaukee prints the mapping outright [1]:
| Bit diameter | Fits pipe through the hole | Who needs it |
|---|---|---|
| 1 and 1-1/8 | 1/2 and 3/4 in pipe | water supply stubs, small conduit |
| 1-1/4 to 1-1/2 | 1 in pipe | drain vents, dishwasher and hose bib runs |
| 1-3/8 | 1 in pipe with clearance | the cabinetmakers' and plumbers' staple |
| 2 and 2-1/8 | 1-1/2 in pipe | branch drains |
| 2-9/16 | 2 in pipe | the trades staple; most-sold large size |
| 3 and up | 2-1/2 in pipe and larger, soil stack work | main drains; low-speed right-angle drill territory |
That mapping is why the 1-3/8 and 2-9/16 sizes dominate shelf space and every kit. If your hole is for cable rather than pipe, buy one size smaller than the pipe logic suggests and read the cable-count rules on our bell hanger bit page instead.
Related guides
Also on this site: ship auger bit sizes for the long deep-boring siblings, spade bit sizes for the fast flat bits below 1-1/2 in, hole saw sizes for diameters past 4-5/8 in, forstner bit sizes for flat-bottomed holes, and wood boring bits compared for the head-to-head decision table with RPM ceilings.
Sources
- Milwaukee HEAVY-DUTY ACCESSORIES Selfeed spec sheet (Gescan distribution copy of the Milwaukee PTA sheet, pulled live 2026-09-23): full 1 to 4-5/8 in ladder with box and clamshell numbers (48-25-1001/1002 through 48-25-4621), shank types (7/16 hex to 2-9/16, quick-change and 3-flat above), pipe-size mapping, feed screws, replaceable arbor 48-07-0201, hex keys, extensions 48-28-4001 to 4016, kit contents: cdn.gescan.com
- Milwaukee PTA Wood Boring Bits catalog page (Ferguson-hosted manufacturer sheet, pulled live 2026-09-23): Selfeed ladder 48-25-1002 to 48-25-4621, plumber and contractor kit contents (49-22-0065, 49-22-0130, 49-22-0135), SwitchBlade overview: fergusonprod.a.bigcontent.io
- Milwaukee Tool product page, Selfeed Bit 1 in 48-25-1002 (pulled live 2026-09-23): category overview copy, feed-screw and cutting-plane features: milwaukeetool.com
- Makita USA product pages, D-29935 (1 in) and D-30031 (2-9/16 in) Self Feed Bit (pulled live 2026-09-23): diameter specs, 1/2 in shank with three milled flats wording, screw-point and outlining-spur copy, 2 in pipe fit on D-30031: makitatools.com, makitatools.com
- Bosch Tools Self-Feed Bits category table (pulled live 2026-09-23): SF1121 to SF4621, working length 3 in, total length 5 in, 7/16 in hex shank with 3-flat on 3 in and larger; extensions EX1006 6 in and EX1012 12 in: boschtools.com
- Makita drill capacity classes (pulled live 2026-09-23): XAD05Z product page rates 2-9/16 in self-feed capacity; DA4031 instruction manual lists 4-5/8 in self-feed capacity at its 300 rpm low gear: makitatools.com, cdn.makitatools.com
- IRWIN Wood Drilling catalog (SPEEDBOR Max Self-Feed table; catalog copy hosted at cupdf, corroborated by src-15 dealer specs, pulled live 2026-09-23): 3046004 1 in through 3046016 4-5/8 in, all 7/16 in shank, 5 in overall length, 2 cutting edges on 3 in and larger, replacement tip packs 1792762/1792763/1792764, family positioning copy (self-feed for pipe and conduit through-holes, Forstner for flat-bottomed blind holes): cupdf.com
- IRWIN SPEEDBOR Supreme product family page (irwintools.com, pulled live 2026-09-23): IWAX2005 1-1/2 through IWAX2009 2-9/16 self-feed bits, all 7/16 in quick-change, 6 in length, with replacement tips: irwintools.com, press release: irwin.mediaroom.com
- Milwaukee 48-25-1372 dealer specifications (pulled live 2026-09-23): 1-3/8 in diameter, 6 in overall length, 7/16 in shank, per PACE Supply and First Supply spec blocks; the same feeds cover 1-1/8 through 2 in at 6 in OAL: pacesupply.com, firstsupply.com
- Milwaukee 2 in and 2-1/8 in dealer specifications (pulled live 2026-09-23): Ballard Industrial prints 48-25-2002 at 6 in OAL and 48-25-2122 at 4-1/2 in OAL; Merrimac Industrial prints 48-25-2122 at 6 in; First Supply prints 48-25-2122 at 4-1/2 in; divergence disclosed in the matrix: ballardindustrial.com, merrimacindustrial.com
- Milwaukee 2-9/16 in 48-25-2562 dealer specifications (pulled live 2026-09-23): DK Hardware prints 6 in length; First Supply, PACE Supply, AIH and Famous Supply feeds print 3-5/8 in OAL; the divergence is disclosed in the matrix row rather than resolved: dkhardware.com, firstsupply.com
- Makita Reference Catalog 2024/2025 self-feed section (pulled live 2026-09-23): Self Feed Bits copy, 7/16 in heavy-duty shank, D-29935 to D-30047 ladder: cdn.makitatools.com
- Makita UK Self Feeding Wood Drill Bits table and product pages (pulled live 2026-09-23): D-74304 25 x 127 mm through D-74429 117 x 127 mm, all 11 mm (7/16 in) shank, 127 mm (5 in) length; per-bit Rpm wood 500 min-1 for 25 to 57 mm and 300 min-1 for the 117 mm bit; extension bars D-35645 5-1/2 in, D-35651 12 in, D-35639 18 in: makitauk.com, d-74304, d-74429
- DeWalt self-feed family index (pulled live 2026-09-23): DW1630 1 in through DW1642 4-5/8 in model map: dewalt.com
- IRWIN 3046004 and 3046013 dealer specifications (pulled live 2026-09-23): 1 in and 2-9/16 in, 5 in OAL, 7/16 in shank, hex/quick-change impact, per The Lumber Yard, Empire Rigging and Kendall Electric spec blocks: thelumberyard.com, empirerigging.com
- Milwaukee SwitchBlade Selfeed Bit 1-3/8 in 48-25-5120 product page (pulled live 2026-09-23): replaceable-blade design, 12 percent faster and 2X life claims: milwaukeetool.com
- Milwaukee SwitchBlade dealer listings (pulled live 2026-09-23): Crescent Electric 48-25-5140 2-1/8 in at 5 in OAL 7/16 in shank; Home Depot 10-piece plumber set 49-22-5100 sizes 1-3/8, 1-1/2, 2-1/8, 2-9/16: crescentelectric.com, homedepot.com
- Makita UK filter facets and the 65/76/92 mm sizes (pulled live 2026-09-23): category filter lists 65 mm (2-9/16), 76 mm (3), 92 mm (3-5/8) diameter options in the 127 mm length family: makitauk.com
- DeWalt DW1639 product page and support article (pulled live 2026-09-23): 7/16 in ball-groove hex quick-change shank, family and multipack contents, DW1646 5-1/2 in extension, DW1650 spare parts: dewalt.com, support.dewalt.com
- DeWalt DW1639 dealer specifications (pulled live 2026-09-23): DK Hardware prints 2-9/16 in diameter, 6 in OAL, 7/16 in ball-groove hex shank; divergence with src-21 disclosed: dkhardware.com
- Pollard Water DeWalt DW1639 listing (pulled live 2026-09-23): 2-9/16 in, length 5 in, 7/16 in hex shank: pollardwater.com