MANUFACTURER VARIES 21MK99 Countersink Deg Hss Uncoated 190735766866 3/4

( Brand: Manufacturer Varies ), ( Type: Countersink-bits ), ( Material: High Speed Steel ), ( Application: For Cast Iron, Heat-treated Stee ), ( Manufacturer Part Number: 21MK99 ), ( Country Of Origin: China ), ( UPC: 190735766866 )

Review MANUFACTURER VARIES Countersink Fl Deg 3/4 Hss Uncoated

The 21MK99 is a high-quality countersink tool designed for use with 3/4 inch high-speed steel (HSS) shank drill bits. This particular model features an included 82 degree countersink flute, making it an excellent choice for creating countersunk holes with a slight outward angle to the sides. The uncoated design of the tool allows for easy sharpening, making it a versatile and long-lasting addition to any toolbox.

The countersink surface of the 21MK99 is specifically designed to create a flat bottom in the center of the hole, allowing for a flush and seamless finish when installing screws or other fasteners. The flute angle of 82 degrees ensures that the tool effectively removes chips and debris as it cuts, reducing the likelihood of clogging and improving overall performance.

Made from durable high-speed steel, the 21MK99 is built to withstand heavy use and wear. Its uncoated finish may require more frequent sharpening compared to coated models, but this also allows for greater customization and control over the tool's edge geometry.

With its versatile design and durable construction, the 21MK99 is an essential tool for any DIY project or professional workshop. Its ability to create clean, countersunk holes with ease and its long-lasting design make it a smart investment for anyone looking to streamline their workflow and improve the overall quality of their projects.

Countersink bits, specifically a 21mm Kukko MK99 model with a 82-degree flute, 3/4-inch shank, and uncoated HSS (High Speed Steel) material, are commonly used for creating pilot holes with countersinks in various materials. Let's discuss the potential advantages and disadvantages of purchasing this type of bit.

1. Durability: The uncoated HSS material is known for its hardness and durability. It can withstand heavy-duty use and resist wear and tear, making it suitable for drilling into various materials, including steel, wood, and aluminum.

2. Versatility: The 82-degree flute design allows for efficient chip removal, reducing the likelihood of clogging and ensuring smoother drilling. Additionally, the 3/4-inch shank size is a standard size, making it compatible with most drill machines.

3. Cost-effective: Uncoated HSS bits are generally more affordable compared to their coated counterparts. This can be an attractive option for those working on a budget or for those who require a large quantity of bits for a project.

1. Requires more force: Uncoated HSS bits may require more force to drill through tougher materials compared to coated or cobalt-alloy bits. This can lead to increased wear on the drill machine and potential user fatigue.

2. Higher risk of galling: Galling occurs when metal-to-metal contact causes the formation of unwanted metallic deposits. Uncoated HSS bits are more susceptible to galling, particularly when drilling into brass or other soft metals.

3. Limited corrosion resistance: The absence of a coating leaves the bit more vulnerable to corrosion, especially when working with water or acidic materials. This can lead to a shorter lifespan for the bit if not properly maintained.

In conclusion, a 21mm Kukko MK99 countersink bit with an 82-degree flute, 3/4-inch shank, and uncoated HSS material offers several advantages such as durability, versatility, and cost-effectiveness. However, it also comes with some disadvantages like requiring more force, higher risk of galling, and limited corrosion resistance.

Considering these factors, this type of countersink bit may be a suitable choice for those working on projects involving various materials and requiring a large quantity of bits, as well as those with a limited budget. However, if you're working primarily with tougher materials, corrosive substances, or need a longer lifespan for your bits, coated or cobalt-alloy options may be worth exploring.

part # 21mk99 price

• $21.04

specifications drillnubbin:

• brand: Manufacturer Varies
• type: Countersink-bits
• material: High Speed Steel
• application: For Cast Iron, Heat-treated Stee
• manufacturer part number: 21MK99
• country of origin: China
• upc: 190735766866

returns drillnubbin:

• paid by: Buyer
• method: Money back
• time: 30 Days
• policy: Returns Accepted

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• credit card: Mastercard
• wallet: Apple-pay
• other

offer drillnubbin:

• options: Ship-to-home
• started: April 11, 2026
• quantity: 97
• sold: 0
• availability: In Stock

shipping drillnubbin:

• class: Standard
• carrier: UPS
• cost: $0.00
• service: UPS Ground
• transit: 4-7 Days
• type: Fixed

general drillnubbin:

• condition: New
• Tools Workshop Equipment > Power Tool Air Tool Accessories > Drill Bits

seller drillnubbin:

• # reviews: 152434
• rating: 99.6%

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