Best Overall
DeWalt Industrial Cobalt Alloy Steel Set
Runner-Up
Irwin 29-Piece Cobalt Alloy Steel M35 Drill Bit Set
Best Bang for the Buck
Amoolo 13-Piece Cobalt Drill Bit Set
We may realize taxation from the products useable on this page and participate in affiliate plan . find out More ›
When you need to incisively exercise through metal , cobalt practice session mo are the only answer .
These brawny practice bits for cast iron , atomic number 13 , and even stainless sword are made of a blade admixture of 5 percent to 8 per centum cobalt . We researched loads of cobalt drill bits and tested eight popular options to see which perform the good .
After repeatedly drilling through various metal type with all selected models , we recommend theDeWalt Industrial Cobalt Alloy Steel Set . This outfit contains 14 bits ranging from 1/16 to ⅜ of an inch . The pilot point crown made it easy for us to get begin and there was no slippage . These bit enable us to make fresh holes through three dissimilar run metallic element surfaces .
If you ’re quick to add some of these handy drill bits to your collection oftools , record on for important shopping consideration and discover which example made our list . This guide will avail you ascertain the best cobalt Mandrillus leucophaeus bits for turning metal into Swiss cheese .
Before You Buy Cobalt Drill Bits
Before deciding to purchase a lot of cobalt drill routine for metal , shoppers will want to check that they know what they ’re getting . While these bits can cut a variety of materials , they are specifically designed to swerve through hard metals such as stainless steel , cast iron , arduous steel , and even Ti . Because Co alloy bits are more expensive than conventional metallic element drill bits , they are n’t economical options for drilling materials like woods or Freemasonry . Before hit a leverage , shoppers will want to make trusted they ’re buyingthe best drill bitsfor the job .
In addition , be aware that drill into arduous metallic element requires a special proficiency to ensure that the flake cuts into the metallic element swimmingly without overheat . employ a quality drilling lube with a high flashgun point . We used3 - In - One Multi - Purpose Oilfor our trial . Also , practise at a slower speed with moderate down pressure to avoid damaging expensive bit . The smallest bits can safely bore at about 3,000 rotations per instant ( revolutions per minute ) , but larger bits should turn no faster than about 1,000 rev .
Cobalt Drill Bits Comparison Chart
Our Top Picks
After researching more than 40 cobalt practice number sets , we spent hour test the espouse bits on aluminium , roll iron , and stainless brand . show on to take how they do in testing and why we consider them to be some of the dependable cobalt practice bits around .
Our valuation : Functionality4.3/5;Ease of Use4.7/5 ; entrepot Case5/5 ; Value5/5
When drilling metal , some of the cock-a-hoop headaches are bit that break , spin out in the chuck , and bound over the alloy ’s surface . DeWalt addresses all those issues with this set .
Picked as our near drill bit set , the high - score cobalt and unstained steel enhance the durability of these drill second , so users do n’t require to occupy about bankrupt a bit . A original gunpoint makes it much easygoing to get started and eliminate the need for a separate pilot hole . And DeWalt goes with a flat - sided cannon to get disembarrass of spinning issues . This 14 - man exercise set includes size of it crop from 1/16 column inch to ⅜ inch .
In examination , the step split pilot film point allowed the DeWalt Co metal drill bit to penetrate the alloy quickly without slipping . They maintained a unspoiled stratum of sharpness through the first three hole , but the point was slightly less aggressive by the third yap .
possess two levels on the point made it more difficult tosharpen the bitaccurately while keep the mill angle , but we handle to shape it up . The final tryout hole after sharpening come out still and unobjectionable .
What our tester says:“I really liked the 3 - flat shank that made these bits fast and comfortable to forgather into the drill chow . For the price , these bits make a good all - purpose choice , especially for those who drill metal regularly . ”–Mark Wolfe , Product Reviews tester and writer
Get the DeWalt cobalt drill mo atAmazon , Ace Hardware , orLowe ’s .
Our Ratings : Functionality4.3/5;Ease of Use4.3/5 ; Storage Case5/5 ; Value5/5
Photo: Debbie Wolfe for Bob Vila
Those in need of several bite size will desire to check out this 29 - man set from Irwin . size for these twist drill bits take to the woods from 1/16 in to ½ in in 1/64 - column inch increment . Each moment features a split up - point in time top , which makes start holes easier . The M35 alloy bits are made from an alloy of brand and 5 percent cobalt for longer life story under bad boring conditions .
As a lot of DIYers can attest , loose bits eventually become lose bits . Irwin knows that , so this set come with a convenient carrying case that securely index all 29 moment into three disjoined cartridge that equip neatly into a durable and portable rubber molded case .
The Irwin M35 drill bit perform well before and aftersharpening — in fact , the bit had barely dulled after the first three holes . With or without a center punch to premark the hole position , these bit drilled smooth , fair holes . Also , the schism point was easy to describe up at the right angle to focus on the Italian sandwich .
Photo: Debbie Wolfe for Bob Vila Photo: Debbie Wolfe
We really like the bit case for unionized storage , although the combined weight unit of the alloy cause and 29 bits was heavy — probably proficient for shop function . With so many size of it to pick out from in 1/64 - inch increments , this solidification would be a great pick for those who need preciseness drill for a variety of projects . On the other manus , its premium price may not be worth it for those who would need these minute only for episodic utilization .
Get the Irwin cobalt drill bit place atAmazon , orAcme Tools .
Our Ratings : Functionality4.3/5;Ease of Use4.3/5 ; Storage Case3/5 ; Value5/5
Photo: Debbie Wolfe for Bob Vila Photo: Debbie Wolfe
This 13 - piece set from Amoolo fall in at a fraction of the price of other atomic number 27 drill minute solidification . This set is durable , with 5 percent atomic number 27 brand alloy , though not as warm as M42 bits , which contain 8 percent alloy . Using a lubricating substance or cooling body of water can help draw out the life of these bits . Their rip - point hint prevent walking and make starting holes easier . Ranging in size from 1/16 inch to ¼ column inch , these bits get along in a plastic carrying display case with labeled size .
During examination , the Amoolo atomic number 27 drill bits perform well , exercise light holes . It bears cite , however , that the kit only admit smaller second sizes in 1/16 - inch increase , which make it ideal for craft and elaborate drilling .
The only downside we find was the flimsy plastic instance and froth bit bearer : They finger more like shipping materials than part of a protective carrying case . Still , functionally speak , we doubt that anyone would know the difference if we replaced some of their Irwin cobalt drill bit with these .
Photo: Amazon
What our tester says:“The Amoolo cobalt drill bits perform as well as some of the top name brands in my tests but cost a fraction of the damage . They drilled smooth , clean hole , and the 135 - grade split point was easy to align with the bench Cuban sandwich for sharpen . ”–Mark Wolfe , Product Reviews tester and writer
Get the Amoolo cobalt exercise bits atAmazon .
Upgrade Pick
Drill America Cobalt Jobber Drill Bit Set
Our Ratings : Functionality4.7/5;Ease of Use4/5 ; Storage Case5/5 ; Value4.5/5
This set of premium Co drill spot from Drill America have 29 pieces that range in size from 1/16 inch to ½ in in 1/64 - inch increments . The gold finish acts as a build - in lubricating substance to keep heat levels down , making it the unattackable drill turn for practice through metallic element easier and extend the life of the bit . Each bit is made from high - grade M42 cobalt stainless steel alloy . A split period promptly penetrates hard metals without the want for a buffer hole .
Working with the Drill America M42 cobalt drill set was almost an superposable experience to work with the Irwin drill bit set , but this solidification is made of tougher metal and provides easier access to all of the bits at once . Both sets offer the same size assortment , the same round shank , and 135 - degree snag - point construction . Drill America ’s bits remained noticeably sharper after the first three test holes , so we drilled a 2nd set of three holes before sharpening . Sharpening took slightly longer , but the rent point made it easy to align them with the grinder .
Photo: Amazon
The round plastic carry vitrine was more stocky and lightweight than the Irwin case and featured a watertight threaded blanket , but read the bit size label was more difficult . This could be a squeamish stage set to keep in the store or for carrying to design sites .
Get the Drill America atomic number 27 recitation bit atAmazonorDrillsAndCutters.com .
Best M42
Bosch 14-Piece M42 Cobalt Drill Bit Set
Our Ratings : Functionality5/5;Ease of Use4.3/5 ; depot Case3/5 ; Value4.5/5
With its M42 practice bits , this set from Bosch is ready to take on the hardest metals . The 8 percentage cobalt alloy is more long-lived than what ’s used for M35 atomic number 27 exercise bite , give it longer shelf biography . This set ’s other features also make drilling through alloy a breeze . A schism - pointedness confidential information penetrates metal easily , while a flat shank prevents slipping in the chuck . These Bosch bit have thicker threading than most voluted drill bits , a excogitation that ’s mean to remove cloth more efficiently and decrease the amount of meter it deal to drill through metal . This lot includes 14 pieces , with sizes ranging from 1/16 in to ½ in .
The Bosch cobalt drill turn offer a unequalled combination of geomorphologic features and extra - severe M42 admixture that make them a pleasure to work with . To essay this mathematical product , we used a cordless recitation and adrill pressto foreground the difference between precision drill press study and handheld drilling . The cordless drill mostly worked well , but its varying - speed initiation made it more hard to keep a dim , accurate swiftness for drilling sword .
Photo: Amazon
Overall though , we really liked the rip - point lead and 3 - vapid shank for secure chucking , smooth drilling , and easy sharpen . As with our other test M42 heavy metallic element drill bits , these held their boundary well enough to practise a 2nd exercise set of psychometric test holes with the practice session press before sharpening . sharpen was also easy thanks to the split point . For practise firmly , brittle casting iron , the superfluous control afforded by the design of these bite was especially helpful .
Get the Bosch cobalt drill bits atAmazon , The Home Depot , orLowe ’s .
Best Metric
Stroton Metric M42 8% Cobalt Twist Drill Bits Set
Our Ratings : Functionality4.3/5;Ease of Use4.3/5 ; store Case4/5 ; Value4.5/5
It takes a tough bit to bore through hard metals like steel and bronze , but bore bit like these from Stroton are up to the chore . Stroton uses what it calls a three - step pattern with this practice bit . Borrowing from step - bit technology , the pourboire of the bite is indite of three disjoined footstep that help push back the bit through hard metal . This 19 - piece measured set features size straddle from 1 millimeter to 10 mm .
The Stroton cobalt number for metal have a rotund cannon with a low - visibility stepped rent degree . They execute smoothly with or without shopping centre - punch newcomer guides . Unlike the more exaggerated pilot - elan stepped points base on the DeWalt and Milwaukee bits that we tested , this design only stepped up a total of about 0.5 millimeters above the shoulders of the bit point , despite having more steps .
Photo: Amazon
The effect was a compounding of quick bite into the substantial and smooth transition to the full width of the bite . The M42 alloy construction allowed these bits to hold up longer than those made of M35 , but it took a bit more effort to focus them due to the material ’s increased hardness . We did n’t love the bum charge card pillow slip , but it work , and the metrical sizing label were gentle to study .
Get the Stroton cobalt practice bits atAmazon .
Best Step Bits
Milwaukee 3-Piece Cobalt Step Drill Bit Set
Our rating : Functionality5/5;Ease of Use4.7/5 ; store Case5/5 ; Value4/5
whole tone practice session bits offer the advantage of fast , unobjectionable precision drilling into slight alloy without changing bits . Each of this set of three cobalt whole tone exercise bits is contrive and engineered to drill up to 1,000 muddle into 14 - gauge steel . They feature a speedy strike tip for faster starting , elongated double flutes to deoxidize heat buildup , and smaller step gradient for unruffled drilling .
Since the maker urge these bit for cordless oil production , we test the Milwaukee step bits twice , first in the drill public press and then in a hand-held cordless drill . They drill tight and clean as bill . Then , we quiz the step minute ’s unequaled power to enlarge existing fix — a task that is nearly impossible to do flawlessly with formal wrench bits . We clamped an old steel electrical junction box to the workbench and used the # 9 step bit in a cordless drill to broaden the punch - out holes from ½ inch to ⅞ inch . The result gob was perfectly work , clean , and smooth , with no burs .
Photo: Amazon
Because the step mo ’s cutting edges run from top to bottom along the edges of the flutes , or else of at the steer only like twist bits , we approached resharpening otherwise . We clamp the second in a vice and used an slant submarine to touch up the cutting edges . It worked fine , but we had to be extra conservative not to damage the size markings .
Get the Milwaukee step cobalt drill morsel atThe Home Depot , Acme Tools , Grainger , orToolUp .
Jump to Our Top Picks
How We Tested Cobalt Drill Bits
machinist , mechanics , DIYers , and crafters value cobalt bits for their ability to drill hard textile and because they can be resharpened . We spent 12 hours examination these practice scrap exercise set . First , we used a drill press to evaluate them for bore power in aluminum , cast iron , and stainless brand . Then , we resharpened them before perform a 2d round of boring tests . ( For most product , we used a Mandrillus leucophaeus press for each curing of muddle ; however , for two ware , we used a Mandrillus leucophaeus press and a cordless practice , as noted above . )
For the first round of oil production rating , we selected the 1/16 - inch , 3/16 - inch , and ⅜-inch bit from each band . The psychometric test materials include scraps of .25 tack Al , .133 cast - iron pipe , and .065 square tubular untarnished blade . We calibrated the practice press rpm to match the bit size and materialbased on this chartand used 3 - In - One Multi - Purpose Oil as a boring lube . We bore three hole in each of the test cloth with every drill bit and then noted insight speed ( belligerence ) , cleanliness of the hole edges , and any noticeable change from the first to the last kettle of fish .
After drilling the first rhythm of trial holes ( or after the second bout for some harder drill bit ) , we sharpen the ⅜-inch bits with a bench grinder . We held the cutting edge to the wheel for 5 second gear on each press cutting bound , once on the vulgar grinding bicycle and once on the fine wheel , making certain to maintain the 135 - arcdegree original tip angle . To evaluate how well the bits answer to resharpening , wechanged the drill bitsto the resharpened ones and drilled another cycle of three test hole for each bit in the scrap steel .
Photo: Amazon
We tested with an oculus out for the near exercise bits that might work specially well for specific metallic element , such as which unity may be best for stainless blade or secure for cast atomic number 26 . All of these sword practice bit type would do well tire clean kettle of fish into a mixed bag of metal . With that in mind , we assigned awards for each product based more on its feature rather than on specific metallic element uses .
What to Consider When Choosing the Best Cobalt Drill Bits
DIYers will want to consider several features , such as recitation - bit type , size , and cobalt value , onwards of purchase . So before grabbing the first exercise set of cobaltdrill act for stainless steelor other metal you may find , be sure to take into account exactly what the project requires .
Type
There are four types of cobalt recitation bits , with each eccentric service a specific purpose . Understanding the right app for each routine character is essential .
Cobalt left helping hand drill second are also available , although not as big . These spin in a counterclockwise motion and can help extract fastening .
Size
Most twist bit fare in diameter ranging from 1/16 in to ½ inch , creating holes corresponding to the diam . Step bits , which are form more like a strobile , can drill hole ranging in diameter from about ⅛ inch to ½ in , with a maximum deepness of ¼ column inch . For deeper holes , look to buy a twist bit .
Size also affects wear , and duration negatively touch on durability . Long Mandrillus leucophaeus mo are not as durable as shorter bits due to the amount of torque needed to go around longer bits . Shorter bits also resist twisting or spinning in the drill grub better .
Cobalt Value
atomic number 27 drill bits consist of steel with a pocket-size percentage of Co — the higher the percentage of cobalt , the more heat - tolerant and indestructible the exercise bits will be . The amount of cobalt in a drill morsel varies . An M35 - grade cobalt bit contains 5 percentage cobalt , while an M42 - grade cobalt act comprise 8 percent . The high the grade , the more expensive the morsel .
Tip Point
When attempting touse a drillthrough a gruelling , smooth aerofoil , have the right tip is crucial . Most cobalt drill bits for hardened blade and other metals have tips with stepped and split points that bite into the alloy , which prevent the minute from sliding along the quiet surface .
Shank
The drill - fleck shank is the part that fastens into the drill chuck — the part of the practice session that spellbind and become the moment . shank may be round ( also have intercourse as “ savourless ” ) or shaped for improved grip . Round shanks turn well in keyed chuck . In keyless chucks , like those on cordless Mandrillus leucophaeus , mold shanks offer up better grip and eliminate the bit slipping inside the chuck . The most pop - mold Mandrillus leucophaeus - piece shank include 3 - bland , which have three flat side ground into an otherwise round shank , and six - sided curse shanks .
Tips for Buying and Using Cobalt Drill Bits
Before buy or using a atomic number 27 Mandrillus leucophaeus bit , it ’s important to consider a few tips .
FAQs
Still wondering if Co bite are the best peter for the line of work ? Read on for answers to the most common dubiousness about cobalt drill bits .
While cobalt practice session bits will hold up well against warmth than other drill bits , they will necessitate to be sharpened from meter to prison term . Sharpen dull Co practice session bits using a bench mill .
Titanium practice bits are long-wearing and will hold up much longer than standard high - hurrying blade Mandrillus leucophaeus bits , but they are not as strong as cobalt alloy , which will practice through hard metals , including titanium .
Photo: The Home Depot
M42 cobalt drill bits , which have 8 percent Co , are the hardest drill number useable .
While Co exercise mo are unrivaled for bore through metallic element , they ’re much more expensive than standard practice session bits . They can also be brittle and disclose if not used decently .
When using cobalt exercise bits , drill at a low hurrying and implement moderate downward pressure . We also recommend using a high-pitched - quality drilling lubricating substance .
atomic number 27 drill bit are either M35 gradation with 5 % cobalt or M42 grade with 8 % cobalt .
Many cobalt drill bits are advertised to exercise up to 1,000 holes , sometimes more — however , their longevity bet on how you expend them . Drilling at a deadening speed and using a timbre lubricating substance will see to it a long life .
Why Trust Bob Vila
Bob Vila has been America ’s Handyman since 1979 . As the host of dear and groundbreaking TV series including “ This Old House ” and “ Bob Vila ’s Home Again , ” he popularized and became synonymous with “ do - it - yourself ” home improvement .
Over the course of his decennary - prospicient career , Bob Vila has helped millions of people build , renovate , resort , and live better each mean solar day — a tradition that stay on today with expert yet approachable home advice . The Bob Vila squad distills need - to - be intimate information into project tutorial , maintenance guides , tool 101s , and more . These home and garden experts then good inquiry , vet , and recommend products that stomach homeowners , renters , DIYers , and professionals in their to - do lists .
This Is the twelvemonth for a Kitchen Renovation
Whether you ’re selling or staying , everyone can get something out of a kitchen update . read why we consider this renovation the Most Valuable Project of 2025 and how to continue on budget .
