14 best counterbores
A counterbore is a specialized cutting tool used in machining and woodworking. It is related to drill bits and is often used in conjunction with them. Here's what you need to know about counterbores:
Purpose: A counterbore is designed to create a flat-bottomed hole with a larger diameter than the hole created by a standard drill bit. It is typically used to provide a recessed seat for a bolt head, screw, or other fasteners. This helps ensure that the fastener sits flush with the surface of the material.
Components: A counterbore consists of two main components:
- Body: The body of the counterbore resembles a cylindrical shaft with a cutting edge at its end.It is designed to cut the larger diameter hole.
- Pilot: At the center of the counterbore's body, there is a smaller pilot hole that helps guide the tool and keeps it aligned with the existing hole created by the drill bit.
Usage: Counterbores are used after a hole has been drilled with a standard drill bit. The drill bit creates the initial hole, and then the counterbore is used to enlarge the top portion of the hole to the desired diameter and depth. This process is common in applications where it's essential for fasteners to be flush with the material's surface, such as in woodworking, metalworking, and construction.
Types: There are different types of counterbores available, including:
- Straight Shank Counterbores: These have a straight shank and are typically used in hand drills or drill presses.
- Taper Shank Counterbores: These have a tapered shank and are often used in machine tools like milling machines.
- Interchangeable Counterbores: Some counterbores have replaceable cutting heads or pilots, allowing for versatility and easier maintenance.
Materials: Counterbores can be made from various materials, including high-speed steel (HSS), carbide, and cobalt. The choice of material depends on the specific application and the type of material being worked on.
Applications: Counterbores find applications in a wide range of industries and tasks, including:
- Woodworking: They are used to create recesses for screws or plugs.
- Metalworking: Counterbores are employed to prepare holes for bolt heads or nuts in metal parts.
- Construction: In construction, counterbores are used for various fastening applications.
Safety: When using counterbores, it's important to follow safety guidelines, including wearing appropriate protective gear such as safety glasses and ensuring the workpiece is securely clamped to prevent movement during drilling.
Counterbores are valuable tools for creating clean and precise recesses for fasteners, ensuring that they are properly seated and flush with the material's surface. They are widely used in both professional and DIY applications, providing a reliable way to improve the appearance and functionality of fastened connections.
Below you can find our editor's choice of the best counterbores on the market
Accusize Industrial Tools H.S.S. Solid Cap Screw Counterbore Set, 3 Flute, Straight Shank, 7 Pc, 508S-0007
Accusize Co., Ltd.
- High Speed Steel
- Straight Shank
- Inch Set (7 PC) : 6#, 8#, 10#, 1/4'', 5/16'', 3/8'', 1/2''
User questions & answers
| Question: | what are the pilot diameters? this data is required in order to verify the drawings currently in the works... thanks |
| Answer: | They are exactly inches, Inch Set (7 Pcs) : 6#, 8#, 10#, 1/4'', 5/16'', 3/8'', 1/2''. |
| Question: | These are not metric converted to the closest inch? I want to be sure that they are measured in Inches, not millimeters |
| Answer: | Hello,Thank you for your interest in our products. I tried to upload a chart to answer your question but Amazon dose not allow pure text pictures to be shown in the product page.Following are the specs, hope the format does not mess up.Screw Size Pilot Diameter Cutting Diameter Shank Diameter Overall Length#6 0.150" 0.242" 7/32" 3"#8 11/64" 19/64" 1/4" 3"#10 13/64" 21/64" 5/16" 3-1/2"1/4" 9/32" 13/32" 3/8" 5"5/16" 11/32" 1/2" 7/16" 5"3/8" 13/32" 19/32" 1/2" 6"1/2" 17/32" 25/32" 1/2" 7-1/2" M3 3.4mm 6mm 7/32" 3"M4 4.5mm 8mm 5/16" 3-1/2"M5 5.5mm 10mm 5/16" 4-1/2"M6 6.6mm 11mm 1/2" 5"M8 9mm 15mm 1/2" 6"M10 11mm 18mm 1/2" 7"M12 14mm 20mm 5/8" 7-1/2" |
| Question: | What size are the pilots? Are they interchangeable with other sizes (such as 3/16" pilots |
| Answer: | We are located in Toronto, Canada, to ship this item to USA address by expedited canada post / UP post are this shipping rate. which takes 5 to 7 business days arrived the US address with registered. if you order more items, the combination shipping will be more competitive. |
| Question: | Why is the shipping so high? Almost 23?cant you charge a better price |
| Answer: | I don't know the CFM. But I use this on my angle die grinder to get in tight spaces without running full speed and shredding aluminum engine components. |
Accusize Industrial Tools 7 Pc Metric Hss Solid Capscrew Counterbore Set, 3 Flute, Straight Shank, 508S-007m
Accusize Co., Ltd.
- Metric Set (7PC): M3, M4, M5, M6, M8, M10, M12
- 3 Flute
- High Speed Steel
- Straight Shank
- Shank sizes: M3-5.5mm/.218", M4-7.9mm/.312", M5-7.9mm/.312", M6-12.7mm/.500", M8-12.7mm/.500", M110-12.7mm/.500", M12-15.8mm/.625"+
User questions & answers
| Question: | Shank size for each bit |
| Answer: | These are three flute co bores and pilots are three flute as well, so measurement of pilots is as follows.. 1/2 is .531 pilot..3/8 is .406 pilot.. 5/16 is .343 pilot .. 1/4 is .281 pilot .. #10 is .204 pilot .. # 8 is .171 pilot .. #6 is .150 pilot Bear in mind I did these measurements with digital dial calipers, so plus or minus .002 is possible. I do not know what tolerances the manufacturer used, so your set may not be exactly the same as mine. |
Accusize Industrial Tools 7 Pc'' H.S.S. Solid Capscrew Counterbore Set 3 Flute Straight Shank, 509S-0007
Accusize Co., Ltd.
- Inch Sizes: 6#, 8#,10#, 1/4'', 5/16'', 3/8'', 1/2''
- H.S.S.; Straight Shank
- Bright Finished
- Premium Quality
- Packed in Solid Strong Wooden Box
User questions & answers
| Question: | Can you tell us want grade steel it is, m2. M7, etc |
| Answer: | Thanks for asking. the difference is not only the strong nice fitted wooden box, This counterbore set made in higher grade High-Speed Steel which is much better than the regular set. Thank you! |
| Question: | What makes these premium vs the regular set? Different steel, or just a wood box |
| Answer: | Shank sizes M3-5.5mm, M4-7.9, M5-7.9, M6-12.7, M8-12.7, M110-12.7, M12-15.8 |
POWLAB 5pcs Counterbore Set High-Speed Steel M3-M8 4 Flutes HSS-AL Straight Shank Counterbore End Mills for Copper, Aluminum, Steel, Cast Iron
Product description
An essential hardware tool for industrial.
Specifications:
Material: High-speed steel.
Drill Quantity:5pcs.
Drill Size: m3, m4, m5, m6, m8.
Package Weight: Approx.130g /4.6oz
Package List:
5 * Counterbore End Mill
- Mill cutters are made of hard high speed steel, usually used to be assembled on milling machine.
- It includes 5 sizes in one counterbore set(m3, m4, m5, m6, m8).Please refer to the size chart for detailed data.
- High toughness, abrasion resistance, high-speed cutting for the high hardness.
- Reduces times of changing tools, improves machine actuator movement efficiency and save mold making time.
- Suitable for milling of copper, aluminum, steel, cast iron, etc.An essential hardware tool for industrial.
Snappy Tools 1/8 Inch x 3/8 Inch 3-Flute Flat Bottom Counterbore with TiN coated twist drill #32408
Make it Snappy
Product description
Use SD-3 Counterbores to drill a pilot hole and counterbore a flat bottomed hole in one step. Perfect for lag screws, lag bolts, washer head screws, T-nuts & more.
- Drive Shank: 1/4 Inch Hex Power Bit Shank
- Drill Size: 1/8 Inch
- Counterbore Size: 3/8 Inch
User questions & answers
| Question: | Can the 3/8" drill be taken out and replaced by a 3/8" rod |
| Answer: | They are not. |
| Question: | is this ok to use on metal |
| Answer: | I purchased two sizes. On the 5/8" counterbore, the bit extends 1-1/2 inches beyond the cutting edge. On the 1/2" counterbore, the bit extends 1-1/4 inches. |
| Question: | How long does the drill bit stick out from the beginning counter sink cutting edge |
| Answer: | You should test this before trying on an assembly. The 3/8 inch counter bore would 1/16 inch from the edge. If your drill center is not dead on center you will break through the radius edge of the plug. I hope this helps. |
| Question: | Can you use this for the 1/2 walnut face wood plugs |
| Answer: | M2 High-Speed Steel, Thank you. |
2 pcs Deburring External Chamfer Tool, Deburring Tool Hard High Speed Stainless Steel Remove Burr Quickly Repairs Tools for Drill Bit Triangle Shank and Hexagon Shank External Chamfer
Mithome
- Safely and Efficiently: Triangle Shank and Hexagon Shank deburring tool can be tightly connected to almost kinds of chuck drills. Three sharp shaving teeth can safely and effectively cut bolts layer by layer without sparks and hurting your hands. Quickly repair bolt . Both threaded and non-threaded stock are available.
- High Quality: Made of high-speed steel, deburring external chamfer tool has very high hardness, strong heat resistance, durable, impact resistant, abrasion resistant, non-breaking, can be reused without corrosion, not deformed and not rust. Deburring tool has strong cutting and repairing capabilities.
- Easy to Use: Facing damaged or deformed bolts, you do not need to spend time and money to find hard-to-find or expensive replacement bolts. You only need to apply the chamfering tool on the drill and then gently apply pressure with the lowest speed to remove burrs. Repair damaged bolts and tighten nuts in place can simplify the maintenance process and provide work efficiency, especially when dealing with non-removable bolts.
- Widely Used: Compact size, you can carry the eliminate damaged extractor in your tool pouch and make hot forming tool, effectively used in Stainless Steel, Hardened Steel, Mild Steel, Copper, Brass, Aluminum, Fiberglass, Wood, Plastic. Fits size(approx.):5/16-32 bolts (.164) up to 3/4″-10 (.750) - (8mm -19mm)
- Our remove burr tools focus on quality, customer experience, and practicality, and are designed to provide people with more convenience in life. If you are not satisfied with this deburring Tool, please contact us at any time to return.
User questions & answers
| Question: | Will this tool sharpen drill bits |
| Answer: | It deburrs any rough edges. Yes it cuts off the unwanted pieces leaving you with a clean thread to put on a bolt (assuming your cutting all thread ) |
| Question: | Does it actually cut or just rubs the end of the screw |
| Answer: | Yes, I purchased this two chamfering tool set, both of which can be mounted on my electric drill, and both use very well. |
| Question: | I want to know if the chamfer tool of triangle shank and hexagon shank can be used on the same electric drill |
| Answer: | Friend, this is a must have for your tool box! Very handy item, and as described, this chamfer tool can be used for 8- 32 bolts (.164) up to 3/4 "-10 (.750)-(4mm -19mm), Works on various length bolts. Makes shortening and rethreading bolts a breeze. |
| Question: | Are they only be used on fixed size screws |
| Answer: | The drill bit can be taken out and replaced |
Product features
Three sharp shaving teeth
Can safely and effectively cut bolts layer by layer without sparks and hurting your hands.
Universally applicable
Hexagon Shank and Triangle Shank chamfer tool can be used in the same chuck drills.
Widely used
Suitable for stainless steel, hardened steel, mild steel, copper, brass, aluminum, fiberglass, wood and plastic pipes.
Applicable size
Suitable for 5/16-32 bolts (.164) up to 3/4″-10 (.750) - (8mm -19mm)
Comparative Advantage
This deburring external chamfer tool had been fully tested, and it indeed serves its purchase in grinding the tip of compressed or rusty bolt to tapered edge so as to tight the nut in place.
Step 1
Install the deburring external chamfer tool on the drill bit.
Step 2
Using the lowest speed on the drill bit, and then slightly applying pressure to remove the burr.
Step 3
Quickly remove the burrs, can easily screw nuts on the bolt.
7pcs/Set Cap Screw Counterbore Set, 6 up to 1/2", Part# 510-001
CME
Product description
7pcs/set Cap Screw Counterbore Set, #6 up to 1/2", part# 510-001
- 7pcs/set Cap Screw Counterbore Set, #6 up to 1/2", part# 510-001
User questions & answers
| Question: | how much run-out can be expected with these (assuming a true running chuck) and are these on-size, undersize, or oversize c-bores? thanks |
| Answer: | No, drill bits are hardened steel and the inserts in this tool are also hardened steel. Its not intended for sharpening. It is a deburring tool for removing burrs from round stock, allthread, bolts, etc. |
Preamer 5pcs M3-M8 Pilot Slotting Counterbore Mould End Mill Cutter Solid Slot Countersink End Mill Drill Bit
Preamer
Product description
Specifications:
Material: HSS-AL
Item color: silver
Weight: 128g(approx.)
Hardness: HRC 65~68
Size:
M3: 5.9 (blade diameter) * 3.2 (boot) * 6 (shank diameter) * 45 (full length)
M4: 7.4 (blade diameter) * 4.2 (boot) * 6 (shank diameter) * 48 (full length)
M5: 9.5 (blade diameter) * 5.2 (boot) * 6 (shank diameter) * 51 (full length)
M6: 11.0 (blade diameter) * 6.2 (boot) * 8 (shank diameter) * 58 (full length)
M8: 14.0 (blade diameter) * 8.2 (boot) * 12 (handle diameter) * 67 (full length)
Package Included:
1 Set(5pcs) x Countersink Mill Cutters
- 5pcs/Set M3 M4 M5 M6 M8 HSS Countersink End Mill Cutters Drill Bits Set 4 Flute Metal Drilling Slot Drill Bit Woodworking Pilot Milling Cutting Tools Set
- Mill Cutter, usually used to be assembled on milling machine.
- Suitable for carved, high-speed machines.Reducing the number of tool changes, improve machine actuator movement rhythm, save mold making time.
- Can milling of copper, aluminum, tool steel, cast iron, etc.
- High toughness, abrasion resistance, high-speed cutting for the high hardness.
User questions & answers
| Question: | Can anyone tell what is being sold here from the description |
| Answer: | As a counterbore tool, it's putting in a counter bore (recess) onto a clearance hole for a bolt to sit below flush of a surface. Typical clearance for a bolt will be +.03 With that much clearance, run-out isn't an issue. With my use in a machine shop, I found them to run pretty true. I did not check the run-out with an indicator, a visual inspection was enough for me. As to being on-size, under size or oversize, the pilot on these counter-bore tools was +.03 of whatever bolt size. Example, the 1/4" tool has a pilot of of .280, this is your standard .03 clearance. For the price, I was very happy with this purchase. |
HHIP 2007-0016 1/4 x 9/32 HSS 3 Flute Solid Pilot Counterbore
HHIP
Product description
1/4 X 9/32" High Speed Steel 3 Flute Solid Pilot Counterbore ~ Cutter diameter is 13/32". ~ Shank diameter is 3/8". ~ Overall length is 3". ~ Continuous pilot counterbores cut rapidly, smoothly and accurately, producing long spiraling chips rather than small metal particles. ~ The pilot extends the full length of the flute portion of the tool. ~ As cutter flutes are ground back due to wear, a new section of pilot becomes exposed. ~ The pilot head may be cut off to any desired length when repeated sharpening makes it too long for practical use. ~ Continuous pilot counterbores have a life many times that of the conventional type counterbore. ~ Cap Screw is 1/4". ~ Pilot Diameter is 9/32".
- Cap Screw 1/4"; Cutter Diameter 13/32"
- Pilot Diameter 9/32"; Shank Diameter 3/8"
- Continuous pilot counterbores cut rapidly, smoothly and accurately, producing long spiraling chips rather than small metal particles Length 5"
- Individual counterbores The pilot extends the full Length of the flute portion of the tool; High speed steel
- Length 3"
21 Pc. 5/16-5/8" HSS Counterbore Set Interchangeable Pilots 3/8" Shank
TrongStar
Product description
Supplied in fitted case.
- Our Part # ALL-10500
- Set includes 6 counterbores: 5/16", 3/8", 7/16", 1/2", 9/16" & 3/4" diameters
- Set includes 14 pilots: .1870", .2040", .2130", .2290", 1/4", 17/64", 9/32", 5/16", 21/64", 11/32", 3/8", 25/64", 13/32" & 7/16"
- Also includes each: 3/8" shank & wrench (shank measures 3.5" overall) Made of high quality High Speed Steel (HSS)
3/8" Interchangeable Pilot Counterbore
Product description
Overall Length - 4 1/16", Shank Diameter - 5/16" x 3 1/16", Pilot Hole Diameter - 5/32". Used in spot facing and counterboring operations. . These counterbores can be used with a wide variety of pilots. The shank diameter of the pilots ordered must be the same as the pilot hole size in the counterbore. We stock a complete range of pilots; please inquire.
- High Speed Steel,
- Short Series
- Straight Shank
Amana Tool - (424000) Face Frame Counterbore No.1
Amana Tool
Product description
Amana Tool® is an industry leader for over 40 years, commitment to offer the highest consistent quality and innovative products. Devotion to consistently providing the highest quality, and providing solutions for manufacturers, fabricators, display and cabinet professionals fabricators, display and cabinet professionals. We are proud to have our corporate headquarters and warehouse, located in new York, U.S.A.
- Amana Tool is an industry leader for over 40 years
- Devotion to consistently providing the highest quality
- Solutions for manufacturers, fabricators, display and cabinet professionals
- U.S.A. Corporate headquarters and warehouse, located in new York
- Commitment to offer the highest consistent quality and innovative products
Amana Tool - (55286) Carbide Tipped Counterbore 1/2 Dia x 1/4 Quick Release Hex Shank
Amana Tool
Product description
Flat bottom counterbores for using round head screws, Hex bolts, etc. Includes pilot drill, #55286, (D) Diameter: 1/2, (D) shank: 1/4, overall length (L): 2-3/4, D1: 1/4, replacement drill: 630-70255286 carbide Tipped Counterbore 1/2 dia x 1/4 Quick release hex shank
- (D) Diameter: 1/2
- (D) shank: 1/4
- Overall length (L): 2-3/4
- D1: 1/4
- Replacement drill: 630-702
Countersink Drill Bit Set Carpentry Tools Countersunk Counter Sink Bit 10mm Width for Woodworking Wood Counterbore 5pcs
- 5 sizes: 0.11'',0.12'', 0.125'', 0.138, 0.157''. Chunk Size: 0.31'' (8mm) -0.39''(10mm)
- High Quality Material: Carbide Countersink Drill Bit Set, High precision, smooth cutting edge, Easy to drill and sink.
- 2-in-1 function: The Countersink Drill Bits Set can save your working time and improve efficiency, because drilling and countersinking work in one step.
- Adjustable Counterbore: Adjustable length of the lower head, with fixing screw, use the attached Hex Key, remove the screw and set the length of the counter bore.
- Great Gift: Good woodworking present for Professional Use and DIY Homeowner. Note - Keep the drill bit vertical during operation. This depth only needs to sink the screw head below the surface.
Product features
Center Positioning Drill
Adjustable Length, Quickly Discharge Chips, provide the stable and safe drilling work
Hex-Key Wrench
Coming with a hex key wrench, adjust drilling depth for screws of various lengths, is not easy to fall off.
Carbide Blade
Sharpened Edge, Quick and Smooth Countersink
Safe and durable design, easy and fast drilling round holes, good for cutting work
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