What size is a hole saw pilot bit?

The standard pilot bit diameter is 1/4 in across the major arbor brands and industrial suppliers, carried in lengths from 3-1/4 in up to 4-1/4 in: DeWalt's DAH99314PB is 1/4 x 3-1/4 in, Milwaukee's 49-56-8010 is 1/4 x 3-1/2 in, its 49-56-8000 is 1/4 x 4 in, and DeWalt's DAH9414PB long pilot is 1/4 x 4-1/4 in. The two main exceptions are Milwaukee's Big Hawg carbide system, which uses a 5/16 in multi-material pilot, and tile-side diamond saws, which use a spring-loaded centering pin rather than a drill.

Are hole saw pilot bits universal?

Mostly. The 1/4 in diameter is close to universal on small (1/2-20) and large (5/8-18) threaded arbors from Milwaukee, DeWalt, Lenox, Bosch, and Greenlee, so a 1/4 in replacement pilot from one brand generally works in another brand's traditional arbor. What is not universal is the shank style and retention: quick-change systems (DeWalt RAPID LOAD, Lenox SNAP-BACK, Diablo Snap-Lock Plus) need a pilot with the matching groove or hex shank, set-screw industrial arbors need a plain shank the screw can bear against, and Milwaukee Big Hawg arbors need the 5/16 in pilot. Match the shank to the arbor socket, not just the diameter.

How do I remove a stuck pilot bit from a hole saw arbor?

Let the assembly cool first, since cutting heat expands the metal and binds the pilot tighter. Back the set screw fully out (Allen wrench, counterclockwise) or, on quick-change arbors, release the retention collar. Soak the socket end of the pilot with penetrating oil and give it several minutes to work in. Then grip the pilot shank with pliers or a small wrench and apply a twisting motion with steady, even pressure while pulling. If it still will not move, tap the arbor body with a rubber mallet or a wood block to break the friction bond, re-oil, and try again. Before reinstalling any pilot, clean the socket with a wire brush and add a drop of oil; debris and dry threads are what seized it in the first place.

What does the retainer on a hole saw pilot bit do?

The retainer is the arbor-side feature that stops the pilot bit from sliding out of its socket while the saw spins and plugs get ejected. There are three common kinds: a set screw that bears on a flat on the pilot shank, a spring-loaded ball detent that snaps into a groove turned in the shank (the quick-change groove on Lenox and DeWalt RAPID LOAD pilots), and Milwaukee's Big Hawg geometry, which locks the pilot in place while still allowing hand removal. A pilot listed as fitting an arbor with a retainer needs that flat or groove in the right spot, which is why plain round-shank pilots can slip in detent arbors and grooved pilots can hang up under set screws.

Why do hole saws need a pilot bit?

A hole saw is a ring of teeth with no centering point of any kind, unlike a twist bit whose tip at least has a chisel edge to seat in a punch mark. Spun against a flat surface, the cup skates and orbits instead of cutting a circle where you marked it. The pilot bit protrudes past the teeth, drills a small center hole first, and mechanically anchors the whole assembly on the mark so the cup cannot wander; it also gives the plug something to be pushed off of afterward. Without it, the saw is close to unusable on flat work.

Can I use a regular drill bit as a hole saw pilot?

Often yes, if three things line up: the shank is 1/4 in to match the socket, the overall length is enough to protrude past the cup teeth (about 3-1/4 in overall in a standard arbor), and the shank style suits the retention system, meaning flats for a set screw or a groove for a ball detent. Purpose-built pilots add a 135 degree split point for accurate starts and sometimes a parabolic flute for chip clearing, and abrasive-material work (nail-embedded wood, cement board, stucco) wants the carbide-tipped multi-material pilots instead of plain HSS.

Hole saw pilot bits: what they do, sizes, and compatibility

Every hole saw arbor carries a small drill bit down its center axis: the pilot bit. It protrudes past the saw cup's teeth, drills a 1/4 in hole at your mark before the teeth touch the work, and anchors the whole spinning assembly so the cup cuts a circle where you marked instead of skating across the surface ^[1] ^[2]. This page is the reference for that bit: the standard diameter and the length ladder across brands, which shank style fits which arbor socket, how the retainer systems hold the pilot in, why pilots use a 135 degree split point, how to get a seized one out, and how to order the right replacement. The saw cup itself has its own pages: the hole saw size chart for which diameter a job needs, and the hole saw arbor size chart for the threads, shanks, and chuck mapping of the arbors these pilots ride in.

What the pilot bit actually does

A hole saw is a ring. Unlike a twist bit, whose chisel edge can at least seat in a punch mark, the cup has no centering feature at all: put one against a flat board, pull the trigger, and the teeth grab unevenly and push the saw sideways, wandering off the mark and gouging the surface. The pilot bit solves that. Because it sticks out past the teeth, it drills a small center hole first; the arbor is then mechanically pinned to the work through that hole, and the cup cannot orbit around anything but the mark ^[1] ^[2]. Empire Abrasives lists the pilot's jobs as locating the cut, keeping the saw stable through the hole, and helping eject the spent plug afterward ^[1]. Milwaukee describes the same role for its pilot drills: accurate hole placement, from the 135 degree split point down ^[3].

That anchor job is also why the pilot is the most abused part of the assembly. It takes the full side load of a wandering cup, it drills the hardest material first, and it is the piece that hits nails and debris ahead of the teeth. Arbors are built around that fact: nearly every threaded arbor from every major brand carries a replaceable pilot rather than a fixed one, and the replacement is a cheap standard bit rather than a new arbor ^[2] ^[14].

The short answer on size

The pilot drill diameter is 1/4 in, close to universally. Milwaukee states 1/4 in as the standard pilot for its arbors, Ruko grounds its replacement pilots to 6.35 mm (exactly 1/4 in) to DIN 1412 C with a split point, and McMaster-Carr fits 1/4 in pilot drills in its industrial arbors ^[2] ^[14] ^[13]. Length is where brands differ: the common ladder runs 3-1/4, 3-1/2, 4, and 4-1/4 in overall, with the long sizes existing so the pilot still leads the cup on deep-cut saws and thick stock ^[7] ^[9]. Two families leave the 1/4 in standard: Milwaukee's Big Hawg carbide-tooth system uses a 5/16 in multi-material pilot ^[18] ^[19], and diamond hole saws for tile use a spring-loaded carbide centering pin instead of a drilled pilot ^[20] ^[21].

Pilot bit size and compatibility chart

The chart below is organized by arbor class, because that is what the pilot has to fit. Thread terms are only labels here: which cup diameters go with 1/2-20 versus 5/8-18, and which shank fits which chuck, is the arbor page's job, and the hole saw arbor size chart owns that table in full. Every row is sourced from at least two independent listings.

Hole saw pilot bits: diameter, shank style, and length by arbor class
Arbor class / system	Pilot shank style	Pilot diameter	Typical overall length	Representative part numbers	Sources
Small threaded arbor (1/2-20 thread)	Round shank with flats or quick-change groove	1/4 in	3-1/4 to 3-1/2 in	DeWalt DAH99314PB, Lenox LXAH99314PB, Klein 31907, Milwaukee 49-56-8010	^{[3] [5] [6] [7]}
Large threaded arbor (5/8-18 thread)	Round shank with flats or quick-change groove	1/4 in	3-1/4 to 4 in	Lenox 1L to 6L arbors, Greenlee 39893, Milwaukee 49-56-8000	^{[6] [10] [12]}
Long-reach pilots for deep cups and thick stock	Round or hex shank, grooved	1/4 in	4 to 4-1/4 in	DeWalt DAH9414PB, Greenlee 39873 (4-1/8 in), Milwaukee 49-56-8000	^{[8] [9] [10] [12]}
Quick-change collar arbors (DeWalt RAPID LOAD, Lenox SNAP-BACK / 2L QC)	Round shank with quick-change groove	1/4 in	3-1/4 in	Lenox LXAH99314PB, DeWalt DAH99314PB / DAH9414PB	^{[6] [9]}
Diablo Snap-Lock Plus mandrels	1/4 in hex shank	1/4 in	2-3/8 in cutting depth (60 mm)	Diablo DHS4BITII (for 5/8 to 6 in Diablo cups)	^{[15] [16]}
SDS-Plus mandrels and masonry arbors	Plain 1/4 in shank (included 4 in pilot); TCT pilot for concrete and brick	1/4 in	4 in	Diablo DHSARSDS (includes 4 in pilot); SDS-Plus carbide-saw arbors with TCT pilots	^{[17] [22]}
Industrial set-screw arbors (McMaster, Ruko)	Hex or round shank under a set screw	1/4 in (6.35 mm)	3-1/16 to 4-5/16 in (82 mm Ruko)	McMaster 4066A-series pilot drills, Ruko DIN 1412 C pilots	^{[13] [14]}
Milwaukee Big Hawg with carbide teeth	3-flat straight shank	5/16 in	4 in	Milwaukee 49-56-9300 (fits Big Hawg arbors)	^{[18] [19]}
Carbide multi-material pilots for abrasive work	Round shank, RAPID LOAD compatible	1/4 in	3-3/4 to 4-1/4 in	DeWalt DAH9314CTPB / DAH9414CTPB, Milwaukee 49-56-9300	^{[18] [23]}
Diamond hole saws for tile and stone (Bosch AutoStart)	1/4 in hex shank, spring-loaded retractable	Carbide tip, not a drill	Sets its own depth (retracts)	Bosch HDGPB6, for 3/4 to 4-1/8 in diamond cups on PCM mandrels	^{[20] [21]}

Read the length column as a ladder, not a standard. DeWalt's naming shows the pattern plainly: DAH99314PB is the 3-1/4 in standard pilot and DAH9414PB is the 4-1/4 in long pilot for the same arbors, with the deep-cut cup deciding which you need ^[7] ^[9]. Milwaukee splits the same way at 3-1/2 in (49-56-8010) and 4 in (49-56-8000, with 2 in of flute) ^[3] ^[10] ^[11], and Greenlee offers 3-1/4 and 4-1/8 in pilots for its arbor line ^[12]. Nothing about the arbor thread changes with pilot length: a 4 in pilot drops into the same 1/4 in socket as the 3-1/4 in one it replaces ^[6] ^[9].

Shank styles: round with flats, grooved, hex, slotted

The shank is where compatibility actually lives, because it has to satisfy the arbor's retention system, not just fill the hole. Four styles cover the market.

Round with flats: the classic. Milwaukee's pilots are round shanks with flats (its listing says one flat, retail listings describe the same bit as round with three flats) so the arbor's set screw or socket can bear on metal instead of polishing a round shank ^[3] ^[4]. The flats stop the pilot spinning independently of the arbor under load.
Round with a quick-change groove: Lenox's LXAH99314PB is the type specimen, a 1/4 in round shank with a groove that Lenox states fits its 2L QC and 5L SNAP-BACK quick-change arbors and the 1L through 6L traditional arbors alike ^[6]. DeWalt's RAPID LOAD pilots work the same way, locking into the collar by groove while still seating in standard arbors ^[9] ^[10].
Hex shank: Diablo's Snap-Lock Plus system uses a 1/4 in hex pilot (DHS4BITII) whose flats give the mandrel a positive grip, and McMaster's industrial arbors take hex-shank pilot drills retained by a set screw bearing on the flats ^[15] ^[13]. Bosch's HSP-HS tile-side pilot is hex-shanked too ^[6].
Slotted and specialty: deep-plug and SDS-Plus systems carry their own pilot forms, like the 4 in pilot included with Diablo's SDS Snap-Lock Plus mandrel or the tungsten-carbide pilots fitted to masonry carbide-saw arbors for concrete and brick work ^[17] ^[22].

Practical rule: match the shank to the socket's retention, then check the diameter. A plain round shank in a detent-style arbor slips; a grooved pilot in a set-screw arbor usually works but lets the screw seat in the groove, changing its stick-out. When in doubt, buy the pilot the arbor manufacturer lists for that arbor: every brand publishes the pairing, and the rows above give the part numbers.

The retainer: how the pilot is held in

Search listings call it a pilot bit "with retainer": the retainer is the arbor-side feature that keeps the pilot from sliding out while the assembly spins, plugs get pushed out, and the drill changes hands. Three mechanisms cover nearly everything on the market. Set-screw retention: a hex-socket screw bears against a flat on the shank, the industrial standard on McMaster and Ruko arbors ^[13] ^[14]. Ball-detent and groove retention: a spring-loaded ball in the arbor snaps into the groove in the pilot shank, which is exactly what the Lenox quick-change groove and DeWalt RAPID LOAD groove are for, released by sliding the collar ^[6] ^[9]. Proprietary geometry: Milwaukee's Big Hawg pilot "locks the hole saw pilot bit securely in place while also allowing for easy bit removal" through its exclusive shank geometry ^[18]. Knowing which one your arbor uses tells you both which replacement pilot fits and how to release it when it seizes, which is the next section.

135 degree split point versus 118 degree conventional

Nearly every purpose-built hole saw pilot carries a 135 degree split point, and the reason is the pilot's whole job description. A split point is self-centering: splitting the web at the tip eliminates the chisel edge, so the bit starts cutting on contact instead of skating, which is precisely the behavior you need from the bit that anchors a hole saw ^[3] ^[25]. Milwaukee states it as "135 degree split point provides accurate hole placement" ^[3]; DeWalt says the same of its pilots, that the split point "easily penetrates steel and minimizes walking" ^[8]. The conventional 118 degree point is the general-purpose grind on ordinary twist bits; it is not self-centering and normally wants a center punch to keep it seated ^[25]. On curved stock such as pipe and conduit, the difference is larger still: field testing of the DeWalt pilot found the 135 degree tip bites more confidently than a 118 degree grind when the surface is not flat ^[9]. For how these angles are ground and maintained, see drill bit sharpening, which owns that how-to; for bit materials and coatings generally, drill bits by material.

How to get a stuck pilot bit out of an arbor

Pilots seize, and the search demand for it is real. It happens for three reasons: the set screw was never fully backed out, heat from the cut expanded the pilot in its socket and it cooled locked, or debris and corrosion wedged in the interface ^[23] ^[24]. Work through the steps in order; each one is cheap and the next one is not.

Let it cool. Cutting heat expands the pilot relative to the arbor bore; removing it hot fights that interference. Cool metal comes apart easier ^[24].
Release the retention fully. Back the set screw completely out with an Allen wrench (counterclockwise), not just loose; on collar-and-detent arbors, slide the release collar to free the ball from the groove ^[23] ^[6]. A half-backed screw quietly pins the pilot.
Penetrating oil, then patience. Soak the socket end of the pilot where it enters the arbor and give the oil several minutes to creep into the joint; guides agree this is the single highest-value step for a bit stuck tight ^[23] ^[22].
Grip and twist. With pliers or a small wrench on the pilot shank, apply a steady twisting motion with even pressure while pulling, not a jerk; uneven force bends the pilot or batters the socket ^[22] ^[23].
Break the friction bond. If it still will not move, strike the arbor body (never the pilot tip) with a rubber mallet or through a wood block to shock the joint, then repeat the oil-and-twist cycle ^[23].

Prevention is the same list run backward: clean the socket and the shank with a wire brush when you swap pilots, put a drop of oil on the shank before reinstalling, and do not overtighten the set screw against a dirty flat ^[23] ^[24]. Pilots are consumables; a shank scarred from repeated pliers extraction is a pilot ready to be replaced, and the next section says how to order its successor.

Choosing a replacement pilot

Three questions, in order. One: what diameter does the arbor take? For nearly every threaded arbor that is 1/4 in; Big Hawg arbors take the 5/16 in Milwaukee pilot and nothing else ^[2] ^[18]. Two: what shank style does the socket retain? Set-screw sockets want plain or flatted shanks, detent systems want the groove, Snap-Lock Plus wants the 1/4 in hex ^[13] ^[6] ^[15]. Three: does the work need more than plain HSS? Nail-embedded wood, cement board, shingles, plaster, and stucco are where the carbide-tipped multi-material pilots earn their price: Milwaukee rates its 5/16 in Big Hawg carbide pilot for exactly that list, and DeWalt's DAH9314CTPB and DAH9414CTPB carbide pilots target concrete block and fiber cement ^[18] ^[10] ^[23]. For stainless-heavy hole saw work, a cobalt pilot reduces replacement cycles; the HSS split-point pilots hold up in everything softer ^[9].

The tile side is its own world, and the exception is by design. Diamond hole saws for porcelain, granite, and stone do not use a drilling pilot at all: Bosch's AutoStart HDGPB6 is a spring-loaded, retractable carbide centering pin on a 1/4 in hex shank that scratches a starting divot for the diamond rim, then retracts out of the cut as the saw engages; it is explicitly not meant to drill through the material, and it fits Bosch's PCM-series diamond mandrels for cups from 3/4 to 4-1/8 in ^[20] ^[21]. Wet-cutting rules and the full tile technique live on our how to drill into tile page. For the metal side of hole sawing, speeds and lubrication are covered in how to drill through metal, and for which cup diameter the job needs, the hole saw size chart.

Related guides

For the cups themselves: hole saw sizes by job and wood boring bits compared for when a spade bit or Forstner beats the saw. For the arbors these pilots ride in: the hole saw arbor size chart. For bit materials and coatings: drill bits by material and drill bit coatings compared. For speeds: the drill speed chart. For the screws that go into the holes hole saws make way for: the pilot hole chart.

Sources

Empire Abrasives, Hole Saw Arbors: arbors carry the pilot drill that centers and stabilizes the cut and aids plug removal; arbored vs non-arbored definitions; 1/4 hex 1/2-thread and 3/8 / 7/16 hex 5/8-thread arbor classes (empireabrasives.com/hole-saw-arbors)
Tool Army, Hole Saw Arbor Compatibility: 1/4 in pilot bit is the standard across Milwaukee, DeWalt, Bosch, Lenox arbors; 1/2-20 and 5/8-18 UNF thread classes shared across brands (toolarmycompany.com/blogs/universal/hole-saw-arbor-compatibility)
Milwaukee Tool, High Speed Steel Pilot Bit 1/4 in x 3-1/2 in (49-56-8010) product page: 135 degree split point for accurate hole placement, 1-flat shank won't slip in arbor or chuck, parabolic flute, Thunderbolt tapered web (milwaukeetool.com/products/details/49-56-8010)
Amazon, Milwaukee 49-56-8010 pilot drill listing: shank size 1/4 in, shank shape round w/ 3 flats, HSS, pilot drill size 1/4 in dia x 3-1/2 in, fits all hole saw diameters (amazon.com/dp/B000BQM8FI)
The Home Depot, Klein Tools 31907 listing: 1/4 in x 3-1/4 in replacement pilot bit for hole saw arbors (homedepot.com/p/301000756)
Campbell Hardware and Supply, Hole Saw Pilots and Mandrels catalog page: Lenox LXAH99314PB 1/4 in dia x 3-1/4 in round shank HSS pilot with quick-change groove fitting 2L QC and 5L QC SNAP-BACK arbors plus 1L through 6L traditional arbors; Bosch HSP-HS hex-shank pilot; DeWalt arbor compatibility notes (store.campbellhardwareandsupply.com/category-s/613.htm)
National Hardware Group, Arbors Pilots and Mandrels collection: DeWalt DAH99314PB 1/4 in 3-1/4 in long x 1/4 in dia pilot; DeWalt DAH99414PB 4-1/4 in long x 1/4 in dia pilot; Lenox LXAH99314PB 1/4 in HSS 3-1/4 in (nationalhardwaregroup.com/collections/arbors-pilots-mandrels)
DeWalt Canada, Replacement Hole Saw Pilot Bits (DAH9414PB) product page: 135 degree split-point pilot bit easily penetrates steel and minimizes walking; hardened HSS construction for commercial applications (dewalt.ca/product/dah9414pb)
Toolstash, DeWalt Hole Saw Pilot Drill Bit DAH9414PB hands-on review: 1/4 in shank, 4-1/4 in overall length, fits standard non-quick-change arbors and RAPID LOAD tool-free systems via the shank groove, 135 degree tip bites more confidently than 118 on curved stock, step up to a cobalt pilot for stainless-heavy work (toolstash.com/tools/Vg73Fd-hole-saw-pilot-drill-bit-1-4-dah9414pb)
Toolup, Milwaukee 49-56-8000 listing: 1/4 in x 4 in HSS pilot bit, Thunderbolt tapered web, 135 degree split point, 3-flat shank won't slip in arbor or chuck, parabolic flute (toolup.com, SKU 49-56-8000)
North Coast, Milwaukee 49-56-8000 spec sheet: diameter 1/4 in, overall length 4 in, flute length 2 in, shank diameter 0.25 in, 135 degree split point starts on contact to keep the bit from walking, recommended for portable drills (northcoast.com/product/detail/90334)
Acme Tool, hole saws and arbors catalog: Greenlee 39893 1/4 in x 3-1/4 in pilot bit; Greenlee 39873 1/4 in x 4-1/8 in pilot bit for 37157 hole saw arbor; Klein 31907 1/4 in x 3-1/4 in replacement pilot; DeWalt DW1808 long pilot superseded by DAH9414PB (acmetool.com, Hole Saws and Arbors)
McMaster-Carr, Hole Saw Adapters: arbors with pilot drill bit in 3/8 in and 7/16 in hex shanks for 1/2-20 and 5/8-18 threads, 1/4 in dia x 3-1/16 in HSS pilots standard, 4-5/16 in pilot on the 7/16 in 1/2-20 arbor; Replacement Pilot Drill Bits and Long-Life Pilot Drill Bits categories; set screw drive retention (mcmaster.com/products/hole-saw-adapters)
Ruko arbor holders spec sheet via AutomationDirect: HSS pilot drill 6.35 mm (1/4 in) x 82 mm ground to DIN 1412 C with split point, fitted to 7/16 and 3/8 hex holders with 1/2-20 UNF and 5/8-18 UNF threads (cdn.automationdirect.com, Ruko arbor pilot PDF)
HardwareWorld, Diablo DHS4BITII listing: 1/4 in HSS hole saw pilot bit, 1/4 in hex shank for secure mandrel grip, fits all Diablo Snap-Lock Plus mandrels, 2-3/8 in cutting depth, for 5/8 to 6 in Diablo hole saws, drills wood plastic aluminum metal stainless (hardwareworld.com, item 9W76OV)
Stine Home, Diablo Snap-Lock Plus 1/4 in HSS Hole Saw Pilot Bit listing: fits all Snap-Lock Plus mandrels, 60 mm (2-3/8 in) cutting depth for deeper holes in one pass, tool-free plug ejection (stinehome.com, item 2508406)
The Tool Locker and Fishertools, Diablo DHSARSDS SDS Snap-Lock Plus Mandrel System listings: SDS-Plus shank mandrel fits all Diablo hole saws 5/8 to 6 in, includes one 4 in pilot bit plus 1/2 and 5/8 in thread adapter nuts (thetoollocker.com; fishertools.com/cutting-accessories/sds-mandrel-system)
Milwaukee Tool, BIG HAWG with Carbide Teeth Pilot Bit (49-56-9300) product page: 5/16 in multi-material carbide-tipped pilot bit for nail-embedded wood, cement board, shingles, plaster, stucco; exclusive bit geometry locks the pilot securely in place while allowing easy removal (milwaukeetool.com/products/details/49-56-9300)
Supply House, Milwaukee 49-56-9300 listing: 5/16 in Big Hawg carbide pilot bit, carbide material, paired with Big Hawg Carbide Arbor 49-56-9305; The Home Depot lists it as 5/16 in x 4 in (supplyhouse.com; homedepot.com/p/305188001)
1toptools, Bosch HDGPB6 AutoStart Pilot Bit spec page: 1/4 in hex shank, spring-loaded retractable carbide-tip centering pin for diamond hole saws 3/4 to 4-1/8 in on porcelain granite stone glass; not designed to drill through the material, only to scratch a starting divot, and retracts once the diamond rim engages (1toptools.com/products/b003nu0i4w)
Toolstash, Bosch AutoStart pilot bit HDGPB6 hands-on review: works with Bosch diamond hole saw mandrels PCM38, PCM12, PCMDSPL; covers 3/4 to 4-1/8 in cups; pilot keeps the ring from skating until the rim grooves a track, then retracts (toolstash.com/tools/mp7aHJ-pilot-bit-hdgpb6)
Walmart, SDS Plus hole saw arbor and carbide hole saw kit listings: SDS-Plus arbors for carbide hole saws 1-1/4 to 8 in carry TCT (tungsten carbide tipped) pilot drills for drilling concrete, brick, and masonry; 7/16 hex-end variant for 1/2 in chucks; replacement TCT pilot bits sold separately (walmart.com/ip/2038701095)
Raptor Supplies, DeWalt Pilot Drill Bits catalog: DAH9414PB 4-1/4 in overall length hex shank hardened steel; DAH9314CTPB 1/4 in carbide pilot for concrete and nail-embedded wood; DAH9334MMPB carbide pilots 3-3/4 in (raptorsupplies.com.sg, Dewalt Pilot Drill Bits); Acme Tools listing for DAH9414CTPB: carbide tip optimized for concrete block and fiber cement, RAPID LOAD and non-quick-change compatible (acmetools.com/S0000000105619)
ToolsAdvisers, How to Remove Hole Saw Bit from Arbor and How to Remove Pilot Bit from Hole Saw: friction and heat expand and bind the joint, so let it cool; debris acts as a wedge; penetrating oil applied liberally with time to work for bits stuck tight; pliers or wrench with even pressure; prevention by cleaning, lubricating, and not overtightening (toolsadvisers.com/how-to-remove-hole-saw-bit-from-arbor; toolsadvisers.com/how-to-remove-pilot-bit-from-hole-saw)
Wikipedia, Drill bit: conventional 118 degree point angle versus 135 degree split-point, the split eliminating the chisel edge so the bit self-centers and needs no center punch (en.wikipedia.org/wiki/Drill_bit)