What is CSK hole?
Countersunk Holes A countersink is a tapered hole drilled with a wide outer portion. A common usage of the countersunk hole is to allow the head of a flat head bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material.
What is counter sunk hole?
A countersink (symbol: ⌵) is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. A countersink may also be used to remove the burr left from a drilling or tapping operation thereby improving the finish of the product and removing any hazardous sharp edges.
What drill size is used for normal fit clearance for an M5 socket head cap screw?
Counterbore Hole Size Chart for Socket Cap Head Fasteners (ISO 4762)
| Fastener Size | Pilot Hole Diameter (Close Fit H12) | Pilot Hole Diameter (Normal Fit H13) |
|---|---|---|
| M5 | 5.3 | 5.5 |
| M6 | 6.4 | 6.6 |
| M8 | 8.4 | 9.0 |
| M10 | 10.5 | 11.0 |
How do I specify countersink?
Write the dimensions of the countersink, giving first the diameter of the drill hole, then the angle of the countersink, followed by the diameter symbol and the diameter of the larger hole. This dimension can be given either with a diameter symbol first, or with the word DRILL after the first diameter.
What is a 100 degree countersink used for?
Bugle Head – Countersunk style primarily used in drywall and wood decking. Fillister Head – Smaller diameter and higher profile than round or pan heads allows for deeper slot. Flat 100 Head – Uses a 100 degree angle rather than the standard 82 degree. Used for thinner materials that require a flat head.
What size countersink do I need?
You will want to choose a countersink that is larger than the bolt size of the hole. Countersink diameter = 1.5 x Bolt Size Hole Diameter. Example: 1/4″-20 Bolt – Multiple the diameter (. 250) x 1.5 = 0.375.
How do you measure countersink depth?
QUICKLY MEASURE COUNTERSINK DIAMETERS Simply press the spring loaded, exact angle Gaging Plunger into the countersink and read the dial directly in . 002″ or 05mm diameter increments on the dial face or optional digital indicator. The COUNTERSINK GAGE is a direct reading gage.
How do you specify countersink on a drawing?
How much larger should a clearance hole be drilled for a socket head cap screw?
| USA SOCKET-HEAD CAP SCREWS | ||
|---|---|---|
| Screw dia. | Counterbore dia. | Clearance dia. (close fit) |
| 1/4 | 7/16 | 17/64 |
| 5/16 | 17/32 | 21/64 |
| 3/8 | 5/8 | 25/64 |
What are countersunk screws used for?
Countersunk Screw. A countersunk screw is a type of fastening that sits flush with the surface of the material it occupies.
What is a counterbore and where is it used?
A counterbore (symbol: ⌴) is a cylindrical flat-bottomed hole that enlarges another coaxial hole, or the tool used to create that feature. A counterbore hole is typically used when a fastener, such as a socket head cap screw, is required to sit flush with or below the level of a workpiece’s surface.
What is the angle of the countersunk head screw?
Countersunk-head screws that follow the Unified Thread Standard very often have an 82° angle, and screws that follow the ISO standard very often have a 90° angle. Throughout the aerospace industry, countersunk fasteners typically have an angle of 100°.
How do you calculate drill depth?
A spot drill has a 90-degree point angle, which makes it easy to calculate the depth of a hole to be spot-drilled. You simply divide the diameter of the spot-drilled hole.