Hole saws are quite popular, allowing you to create different size holes in materials for a wide variety of uses. While the hole saw itself is easily identifiable, there are two major types that exist with each having its own uses. The arbored and non-arbored hole saws are similar in some ways, yet different in others.
What is the difference? No, it is not the presence or absence of the pilot bit.
Difference Between Arbored and Non-Arbored Hole Saw
The difference between an arbored vs non-arbored hole saw lies in the arbor or shank design. In an arbored hole saw the shank or arbor is an integral part of the cutting bit. On the other hand, a non-arbored version is designed to use with a detachable arbor. You can use the same arbor (sometimes called a mandrel) with different diameter unarbored hole saws in a set.
Both types of hole saws may appear alike at least at first glance. This is because both types of hole saws are essentially canisters with serrated teeth on one end and may have a pilot bit in the center. Both are designed to cut into materials for the purpose of making holes which range from ½ ″ up to 8″ depending on the external diameter of the hole saw.
For both types, the hole must be punched through the material, which is unlike a Forstner bit that leaves a flat bottom. Not cutting all the way through only leaves a ring or a circular groove and not a hole.
Arbored Hole Saw
The arbored hole saw has a fixed shank and a twist drill in the center known as the pilot bit. This pilot drill bit is used to stead the saw when in action.
When you cut soft materials such as wood, plastic pipes, etc. the pilot bit will create a small hole first, much like a standard drill bit which is then followed by the teeth of the hole saw. Because the drill bit has already penetrated and set in the material, it creates a stable environment for the rest of the saw to cut through the material without walking or drifting.
Walking is when the saw teeth are not firmly set in one place along with the material which means that it may drift away from the desired location when drilling. The pilot bit prevents this from happening as it provides a solid point of contact.
Advantage and Uses
The main use of an arbored hole saw is to create an accurate hole in the material time and time again. Since the fixed arbor is an integral part of the cutting bit, it is rigid and will run with true circularity. The pilot drill ensures that precise location and accuracy are maintained throughout the drilling process. The result is a clean hole that offers several different uses depending on the intention of the hole itself.
However, the material that has been removed will have the pilot hole in the center. This may or may not be desired depending on the purpose of creating the hole.
For example; what is your main purpose for using a hole saw? Do you want to cut a hole in the workpiece or you want to use the round piece cut out from it? In case you want to use the round piece, then do want the piece to have a small hole in the center?
If you need a round piece without the center hole, use the hole saw without the pilot bit.
Non-Arbored Hole Saw
The non-arbored hole saw usually comes without the arbor and the pilot drill in the center. If you buy as a complete set, you will often find one or two arbors and a number of different non-arbored hole saws. The arbor or mandrel is detachable and suits different diameter saws from the same brand.
Hence the key difference between an arbored and a non-arbored hole saw is that the arbored version has a fixed shank and the non-arbored saw has a removable arbor that suits various diameter hole cutters. Otherwise, the function of the non arbored hole saw is quite similar to the one with the arbor.
Pros and Cons
The main advantage of this type of hole cutter is the cost. Non-arbored types usually cost less and they take up less space for storing.
The disadvantage here is that they are less accurate than their fixed shank counterparts and are prone to error concentricity when switching between different diameters.
How to Use a Non-Arbored Hole Saw:
You use a non-arbored hole saw in the same manner as one with a fixed arbor with one exception. Here, when you want to cut a different-sized hole, you need to remove the shank (or mandrel) and attach it to a different size hole saw.
Make sure that you are using the correct mandrel and clean saw and arbor. If dust or debris gets caught in-between, the hole saw may not run concentrically.Important: Both arbored and non-arbored hole saws can have a removable pilot drill bit in the center. Usually, you can loosen the locking set screw and take the bit out to sharpen it or to completely remove it.
Diamond grit hole saws or core bits nearly always are arbored, but they do not have a pilot bit in the center.
Hole Saw without Pilot
Without the pilot bit in the center, when the saw starts to drill into the surface, there is no guiding in place to keep the saw steady.
Generally, you don’t want to remove the pilot drill bit. The exception is that the material which is removed will not have a pilot hole in the center which may or may not be desired depending on what is done with that material.
A hole saw without a pilot drill requires either clamping the workpiece securely or a guiding plate to keep the saw in place. A guiding plate is an external piece that keeps the cutting bit from drifting away from its intended location.
A guiding plate is not required when you have a pilot drill in the center to prevent the saw from going anywhere other than its intended location.
Hole Saw With and Without Pilot – Pros & Cons
There are advantages and disadvantages to each type of hole saw. Understanding them will help you make the best-informed decision about which one is right for you.
Both types of hole saws will have about the same durability assuming they are used in the right manner.
The difference is that when used on handheld drills without a guide plate, the one with a pilot drill will last considerably longer than the saw without it.
Ease of Use
It is also best suited for people of all experiences, especially those who have never used a hole saw before. This is because the pilot bit keeps the hole saw in one place when drilling into the material. The result is an accurate hole is created of the size that is desired.
A hole saw without a pilot bit is desirable for those who want to make use of the material that has been removed without a hole in the center. However, you will need a guiding plate or drill press to make this type of saw work for you.
Carbide-tipped or diamond hole saw without a pilot bit is used for cutting holes in masonry, stones, and tiles.
Accuracy & Speed
If you need the hole in the precise location, use a center punch or center drill bit to mark position first. This does take a little more time if accuracy in the material is a must. But then again, you do not need a guiding plate or use a drill press as with a pilotless saw.
One advantage of not using the pilot is the ease of removing the slug from the hole cutter. This may speed up your work, although at the cost of accuracy.
For those who have experience in cutting out holes in tiles, granite, stones, etc. know that the diamond hole saw comes without a pilot. Having steady hands and experience will help when using this type of saw.
Which One is Best for You?
Ultimately, it comes down to whether you need the material that has been cut out or not. If you are creating holes in the material so you can use what has been cut out, then the hole saw without a pilot is the right choice. It creates a smooth line and does not have a center hole that may damage the material that has been removed.
Conversely, if you do not care about the material that has been removed, then an arbored hole saw with a pilot bit is the better choice. This is because the accuracy tends to be greater thanks to the pilot drill and integral shank.