Dado cuts are similar to rabbet and grooves but with a slight difference. Many methods to cut a dado exist, but using a dado blade set is easier and more accurate.
You must ensure that you aim for the dado’s exact width that will fit the mating wood. Failure to do this will defeat the purpose of a dado in a bookshelf or cabinet design.
Because of this, this article bears key information you need to cut a dado. Consequently, this key information centers around the use of a dado blade set for cutting dados.
Figure 1: A typical dado.
Table of Contents
Section 1: What are dados?
A dado is a three-sided slot carved on the woods’ surface for easy mating of another piece of wood. Often, either glue or mechanical fasteners help to secure the second piece of wood. Unlike a rabbet, which is two-sided, a dado is three-sided, which makes it a more solid joint. With either a special dado blade set, circular saw blade, or router, cutting a dado is possible. However, in the making of cabinets, door panels, drawer bottoms, bookshelves, etc., dados are important.
Figure 1: Stacked dado blade set.
Section 2: Why do we need the dado blade set to cut dados?
While there are other means to cut a dado, using a dado blade set remains the best approach. Some of the reasons for this occurrence are:
- It delivers a precise, clean, and smooth cut that needs no finessing.
- It is versatile; with a dado blade set, you can successfully cut a dado, tongue, rabbet, and half-lap joints.
- It limits wastage by removing just the exact amount of material required for the dado to form.
Section 3: How to cut dados with a table saw and dado set?
3.1 What tools do we need before cutting dado joints?
a. A Table saw
b. A dado blade set
c. A Measuring tape or square.
d. A Pencil
e. A Push stick
f. Safety gears
g. Chisel (optional)
3.2 Choose the right cutting width
The dado’s width must always correspond to the thickness of the mating wood for a perfect fit. Hence, you must put this in mind when setting out to cut your dado. Failure to do the needful checks will amount to the inaccuracy of the final dado joint. Getting an idea of the cutting width will help you in proper stacking and even height setting.
3.3 Stack the dado blade set
The dado blade set is majorly a combination of small blades known as chipper blades with lesser teeth per inch. Typically, you can stack a dado blade set to cut a dado up to 1-inch wide. They come with two outer blades and a couple of inner chippers.
To effectively stack up the dado blade set to the dado’s required width, you need to apply some tricks. You start by dismounting the two outer table saw blades and place them on top of each other. In furtherance, begin to stack the dado blade set until it flushes with the mating wood’s thickness. On the other hand, there are cases when the dado blade set’s combination will not reach the required width. In rare cases such as this, you can use shims to achieve an accurate combination of the dado blade set. To check the extent of the flush between stack and mating wood, you can use a square.
Finally, once you can achieve accurate stacking, you can now mount the table saw blade and dado blade set. This mounting could be with or without the shims depending on the situation at hand. Besides, you should ensure that the blades’ teeth are in the opposite direction.
3.4 Set your table saw blade to the correct height
Since the table saw blade is partly responsible for making the dado cut, it must maintain a certain height. This height refers to how much above the table surface the table saw blade protrudes. Also, this height is usually equivalent to the expected depth of the final dado.
3.5 Set your rip fence
With your measuring tape, you can easily adjust the rip fence and lock it to the appropriate position. With this done, the blades can appropriately pass through the wood’s expected portion during the dado cutting.
If you cannot access a measuring tape, then position the workpiece against the fence to locate the dado’s location. Afterward, then lock in the rip fence and get ready for the main cut. Always ensure that the table saw is never plugged into the mains when carrying out all necessary preparatory settings.
3.6 Cut dados
It is the last and final step to cut the dado on wood. However, it is best to have a scrap wood board to test out your dado cutting set-up. It is known as a test cut, ensuring that the whole set-up is in good working condition. Once you make the cut and everything seems fine, you can proceed with the main wood to make the dado cut. Make sure to put on the right safety gear such as earplugs, goggles, etc., and use a push stick.
Figure 3: A dado joint.
Section 4: Are there other tools that can cut dados?
Yes, a router and a circular saw mounted on a table saw can also cut dados. However, it is more herculean and less accurate than using a dado blade set.
4.1 The ban on dado blade set in Europe
According to the EN and IEC standards, using a dado blade set in the EU is forbidden. The authorities consider a dado blade set unsafe due to the removal of the guard and riving knife. A lot of injuries and accidents have occurred that made the authorities ban its use. For this reason, table saws have short arbors in the EU and cannot accommodate a dado blade set.
4.2 How to cut dados with router/ circular saw?
It does the same job as a table saw and dado blade set but most especially for some purposes. Using a router in combination with a straight bit, you can cut a great dado. The ability to cut a “stopped dado” is one distinct feature of using a router to cut a dado. Generally, when cutting a dado with a router, keep the speed low, and remain patient. You would have to carry out gradual multiple shallow passes. Typically, the depth per each pass ranges between 1/16 to 1/18-inch.
The major reason for multiple passes is to prevent burning of the workpiece or quick dulling of bits. In conclusion, ensure that you use a straightedge to guide the router’s path.
The major difference between using a router and a dado blade set is the accuracy. A dado blade set affords you the ability to set the right width for the expected dado exactly. In comparison, a router will require you to use your discretion and go through multiple passes.
Figure 4: A router cutting a dado.
With your traditional circular saw blade mounted on a table saw, you can cut a dado with multiple passes. The approach to this method is quite simple. Remember that a typical circular blade has a particular thickness. With this thickness, you can estimate how many passes to make to get the dado’s required width. For instance, for a 1-inch wide dado, you need two passes of a circular saw of ½-inch.
Figure 5: A table saw used for dado cutting.
Section 5: How to avoid getting the rough edges of dados when using the dado blade set to cut?
5.1 Cut dados on oversize board
It is an advisable approach to prevent tear out of the wood’s most fragile fiber. You can then trim down the oversized board to the required dimension once the dado is in place.
5.2 Score the edges
By scoring the edges of a workpiece with a utility knife before cutting the dado, you can avoid rough edges. Although this method works well for plywood.
5.3 Lay down masking tape
It works particularly well around the edges of the dado. Lay the tape around the edges of the cutting line and make sure to pull towards the dado.
5.4 Use a zero-clearance insert
This special insert helps to close up the gap left around the saw blade on the table saw. It prevents tear-out and provides support for the workpiece.
5.5 Use Clamps and Hold-downs
Vibration is inevitable in a table saw, but you can limit its effect by ensuring a firm hold-down of the workpiece. Always ensure to clamp down your workpiece during dado cut; this will prevent any form of error from vibration.
5.6 Take multiple passes
Despite the ability to complete the cut in one pass, taking multiple passes is still the best. As they slowly and steadily win the race, and such is the case in dado cutting. The outcome of a dado cut with multiple passes is usually a clean and fine one.
In summary, we expect you to have learned a thing or two from the pane point of this article. Not only have we talked about setting up a dado blade set, but we also highlighted tips to prevent rough edges. Over the years, NCCuttingtools has built the expertise to provide premium cutting tools for your everyday needs. For all your customized services, consultations, and guidance, do not hesitate to reach out to us now.