Countersinking Setup and Cost
A $9 minimum is added for countersinking to your order. Quantity discounts might save you up to 70% or more! The material, operation type, number of procedures performed on each part, and the number of duplicate parts are all taken into account when calculating quantity discounts. Based on your order, our app will automatically provide quantity savings.
Part Sizing
Because the thickness of the material and the size of the part have a significant impact on the efficacy of countersinking, we've established sizing minimums and maximums that your part must meet:
Minimum part size of 1” x 4”
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Minimum length of the shortest side is 1”
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Minimum length of the longest side is 4”
Maximum part size of 14” x 46”
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Maximum length of the shortest side is 14”
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Maximum length of the longest side is 46”
Materials Available for Countersinking
File Setup and Design Considerations
Confirming countersink placement in our app
You may ensure that your part will work as you meant it to when you upload your file to our app and view it in a 3D model. Make sure your countersinks are positioned correctly on your part by using this model. It's crucial to carefully verify that countersinks are marked on the right face of a part because they can be positioned on either the top or bottom face.
Indicating countersunk holes
Remember that you only need to mention the inner circumference of the hole (referred to as the Minor) that needs to be countersunk when preparing your file for countersinking. Avoid including the outer circumference (the Major, or countersink size) in your file since it will be removed during machining, making your hole too big to countersink. Your document should appear as seen here:
Hole size
The Major hole size should be the same size or slightly larger than the diameter of the hardware head you’re using. It’s best to use the exact diameter of the hardware head as your reference, but a good rule of thumb is to make the countersink 50% larger than the internal hole (Minor).
When selecting your hole operations for the desired hole in your design, we will automatically resize the hole to the required size as long as the starting hole is less than .500” in diameter. Please keep in mind that because they will resize, you will need to verify you have adequate clearance to other features and edges of the material.
You can see examples of countersinking sizing in the chart below. It’s important to note that these examples are based on sample hardware (linked in the chart) and hardware specifications and styles will vary based on the manufacturer.
Imperial/SAE Examples:
Hardware Size | Hardware Head Diameter | Countersink Minor Diameter | Countersink Major Diameter | Countersink Depth |
|---|---|---|---|---|
¼-20, ⅜” Hex Drive Flat Head Screws | 0.531” | 0.250” | 0.531” | 0.161” |
10-32, ⅜” Hex Drive Flat Head Screws | 0.411” | 0.194” | 0.411” | 0.127” |
Metric Examples:
Hardware Size | Hardware Head Diameter | Countersink Minor Diameter | Countersink Major Diameter | Countersink Depth |
|---|---|---|---|---|
M8 x 1.25mm, 12mm Hex Drive Flat Head Screw | 16mm | 8mm | 16mm | 4.4mm |
M5 x .8mm, 14mm Hex Drive Flat Head Screw | 10mm | 5mm | 10mm | 2.8mm |
Depth and angle
Countersinks shouldn't go deeper than 60% of the thickness of the material. Any deeper and you run the danger of compromising the component's and material's structural integrity. If your countersink must be deeper than that, make sure the holes are sufficiently apart from one another to avoid undue tension.
The angle of the countersink is dependent upon the hardware being used. Ideally, the hardware has at least 50% contact with the countersunk hole, but it doesn’t have to match exactly. The standard countersink angle for metric hardware is 90°, and the standard countersink angle for imperial hardware is 82°. We offer sizes in both angles.