Circuit boards or PCBs have various distinct features which directly affect their functionality and physical structure. You can think about some features normally, like the type of material used in PCB and the number of layers one can have in a board. However, there are a few elements that get less concern. This includes the number of holes, their type, and the drilling process. Particularly, some PCBs need screw holes to meet the board requirement; how these screw holes drill into the board matters here the most. Thus, there are two basic methods of drilling holes in a board. Countersink and Counterbore. Each screw call demands distinct types of holes. The type of screws depicts which method you are going to use for drilling holes. Countersink holes, Counterbore holes, or maybe both.
What is Countersink for PCB?
A countersink represents a hole-type drill into a PCB or circuit board. It gives the shape of the cone, which allows the screw or fastener to fit perfectly inside the PCB. Also, these countersink holes have a variety of angle dimensions. The standard countersink hole size ranges the angle between 60, 82, and 90 degrees.
This does not stop here; you may also drill these countersink holes in different sizes at different angles of 100, 110, and 120 degrees. Moreover, Chamber angles countersink holes with 82, 90, and 100 become popular around the industry.
What is Counterbore for PCB?
Counterbore is also a type of hole bore in a PCB or Circuit board. It comes in a cylindrical form with a flat surface. This shape allows giving enough space for the hex head or socket head screw. If your board needs these types of screws for fastening, then a counterbore hole is what you need.
Counterbore holes can only drill at one angle, zero degrees which also needs to keep hole efficiency in mind. This also means that one can only use counterbore holes for solely one purpose. Whereas, unlike counterbore holes, countersink holes utilize for different applications with a variety of angles.
Similarities And Differences Between Countersink Vs. Counterbore For PCB
Countersinking is a process of drilling countersink holes in a PCB. Countersink holes come in a variety of sizes with different angles. The standard angle size includes 90, 82, and 60 degrees, while the less popular size includes 120, 110, and 100 degrees. Well, the most well-known angle sizes include 100, 90, and 82. Whereas, unlike countersink holes, the counterbore hole only has one standard angle size, zero degrees. It acts and affects in the same manner, just like a countersink hole.
You must work efficiently while drilling holes in the wooden surface boards. If by any chance you forget to drill the countersink hole, but later on, force the screw or fastener into a wooden surface. This not only affects the strength and stability of the wood but also affects its look and makes it miserable. This is because the fibers of wood get damaged and cracked easily. However, drilling a counterbore on the surface of wood seems like a good idea as it does not need accuracy and precision in the sizes of angles.
Moreover, all counterbore holes require a socket or flat bottom screw that can suit the surface easily. Counterbores typically serve a sole purpose, whereas countersinks serve various purposes due to a wide variety of angle sizes.
A counterbore hole looks for a tiny coaxial hole opening, whereas a countersink hole looks like a conical shape. This comes in handy when you don’t need a screw or fixture’s head into the surface of HDI. Furthermore, countersink holes can also have various styles and shapes due to their various angles. But countersink holes give the same depth to all the screws.
Countersink Vs. Counterbore Symbol
In design and drawing, the symbol represents the actual technique or material. These symbols provide a space for specification tolerance and dimensional consistency. However, writing symbols or signs of a quantity or material is an easier and faster way than spelling out the complete name. It not only breaks the drawing standards but also makes the work messy.
Symbols indicated the standard protocols in mathematics, design, and drawing. In various projects like a blueprint of a house or drawing, symbols help in conveying information faster. That is why both counterbore and countersink holes have symbols. It mostly writes along with the symbol of diameter and has a figure value.
Symbol of Countersink
The symbol of the countersink hole indicates the alphabet V. The countersunk hole resembles the alphabet V when you look at it from a side posture.
Symbol of Counterbore Symbol
The counterbore hole symbol resembles an unfinished square with a top opening. The symbol comes by taking a look at both counterbore and countersink holes. Both symbols come in handy in the designs of drilling. The emblem of diameter represents the deepness and wideness of a hole in a board. A designer depicts these values based on data provided in such designs. The symbol of counterbore defines the operation of counterboring, while the symbol of countersink defines the fastening operation of countersinking.
Countersink Vs. Counterbore Drill Bits
You can drill many holes with the drill bit. Based on the material thickness and the desired diameter. Both the countersink and counterbore use hole drills to commence the process. At the same time, drill bits are used to create countersink and counterbore holes inside a PCB or the material. Both drill bit holes use a distinct type of material for manufacturing. Basically, their main goal is to fit the fastener or the screw into the workpiece of the washer.
One cannot ignore the axis and the length of the crew or the fastener in the counterbore or countersink hole. Different materials are utilized for fabrication due to the cavity distinction of both types of holes. A type of cylindrical hole bores inside the surface of the material for counterboring. This hole contains a small diameter at the bottom and a large one at the top.
The main goal of the hole is to hold both surfaces firmly so that they won’t separate from each other. The head of the fastener goes into the larger edge while the shaft goes into the smaller side. Therefore, drill bits of countersink come in a variety of sizes and styles to adjust various projects at different angles. There are four basic types of drill bits for the countersink. This includes flip-style, rocker pro, cross-hole, and fluted bits countersink.
When to use Countersink Drill Bits?
Make sure to match the size of the drill to the screw while using drill bits of countersink. A too-large countersink hole swallows the fastener or screw head. At the same time, a tiny hole doesn’t allow the screw head to fit into the board. This leads to an unfit mount. However, a question arises, what if you put the screw inside the hole forcefully? Undoubtedly, if you try to drive the screw forcefully into the hole, it may damage the material surrounding it. This happens with both wooden and HDI surfaces.
Same as if the hole is too wide, the screw will get shallow, while if the hole is too shallow, it will not allow the screw to fit inside the surface. Therefore, measurements play an essential role in the whole drilling process. To get perfect measurements, adjust the setting of the countersink. The setting includes the size of the countersink, the depth of the drill bit, and the stop location of the center. However, it’s still recommended to first practice these measurements over the piece of scrap material. So that you adjust the setting beforehand if something goes wrong.
Furthermore, never drill faster to prevent chattering. As it leads to uneven design on the surface of the material. Also, it does not allow the fastener to fit, which makes your board or material messy and unusable.
Using Countersink & Counterbore In PCB
With an understanding of the basics of both countersink and counterbore holes, let’s dive into their usage in the PCB. However, both types of holes are mainly used in wooden and metal surfaces, but they will also go well for a PCB. PCB also has holes that use drilling techniques, and each hole in the PCB counts and matters. Some use screw holes. It helps in attaching the Device with a PCB. The type of screws you want to drill determines the types of holes you will use in the PCB. A counterbore or a countersink hole.
· Limited Space & Mounting Security
The Countersink hole plays a vital role in your PCB having compact or less space. It helps in adding additional features like enhancing the flexibility of the device. This conical-shaped countersink hole is a typical type of flat-head screw that requires greater precision and accuracy as compared to counterbore holes. Once the fastener or screw fits into the board, later it becomes easy to adjust the circuit inside the device. The device may include a watch or a smartphone. A counterbore is easy to drill. However, it does not fall into an ideal choice for most PCBs.
Countersink holes do not affect the surface of the board and keep it smooth if drilled correctly. Also, it does not disturb the arrangement of a PCB. However, counterbore holes come in if you need secure mounting in a PCB beside a smoother surface or converse space. These holes provide enough space to fit the socket fixture. Therefore, these holes and screws make stronger connections. But if you need to conserve surface, then use countersink holes.
Applications of Countersink Vs. Counterbore
A PCB use is mounted through a screw into a hole. Therefore, both counterbore and countersink holes can use for stronger and safer installation. Engineers use automated equipment manually to commence this process. A counterbore hole is drilled with a grub fastener or screw. This gives an ideal base for a screw to fit perfectly inside the hole.
Countersink Vs. Counterbore – Uses
In PCBs, countersink holes provide perfect fitting and smooth installation into compact devices. PCB countersink mostly includes small wearables and smartphones. A counterbore hole provides a tight fit to a screw in a cylindrical manner. Due to its flat bottom, it uses a socket cap-type screw. This socket screw contains a hex head which needs safe and secure mounting in a PCB. The application of this type of PCB includes electronic devices, like washers which need secure and tight fitting.
Dimensioning Techniques of Countersink Vs. Counterbore
Dimensioning plays a vital role in the design process. This allows the designer to convert the drawing into real life. Dimensioning mainly depicts the type, size, and material texture used during fabrication and construction. Dimensioning methods express counterbore and countersink holes in a chart or a design through various dimension abbreviations and symbols. These depict the type of surface and provide zero restriction over the fabrication method. However, these dimensions typically refer to the note and are followed by hole size.
How To Dimension A Countersink & A Counterbore?
The angular edges in a countersink process go through the recession to provide a fit to flathead fixtures head which can be rivets, screws, or bolts. During drawing, it provides the diameter of the surface, its angle, drilled hole, its diameter, rise, and depth. The cylindrical part and flat bottom of a counterbore allow the head of the fastener to fit in a recessed part.
During drawing, it provides the depth, diameter, and radius of the corner. In some scenarios, the remaining shaft thickness can also be dimensioned in the center. Both countersink and counterbore holes dimension in a polar and rectangular coordinate form.
Conclusion
Both countersink and counterbore holes use different types of screws in distinct types of materials. However, both work in a similar manner in a PCB. A countersink makes a cone-shaped hole, whereas a counterbore makes a cylindrical shape hole. This article briefly explains the definition, similarities, differences, and working principles of both countersink and counterbore holes.
The screw types that fit in countersink and counterbore holes refer as countersinks and counterbore. Both use different types of drill bits for distinct types of materials. Also, this article shows how and when to use these drill bits in a PCB according to their usage and application.
Moreover, it also describes its symbols, different types of dimensioning techniques, and their applications.
