Buying guide for best hole saw sets
There's a limit to how big a hole you can drill with a standard bit. The solution for something bigger in most cases is a hole saw – which can be as large as six inches in diameter.
Different types of hole saws can cut through just about every material you can think of: drywall, wood, plastic, glass, tile, concrete, marble, and steel. They are a valuable addition to every tool kit, whether you are a weekend DIYer or a professional tradesperson.
Given the versatility, it's no surprise that there are lots of hole saw sets to choose from.
Types of hole saws
Most hole saws are comprised of an arbor, a metal cup with a toothed edge, and a pilot drill. The metal cup usually has straight sides – which makes it easier to cut a parallel hole – though some have sloped sides, which reduces friction or any chance of them binding in thick material. Not all models have a pilot drill, but it's usually included because without it, the hole saw has a tendency to wander – making it difficult to position accurately.
There is another tool called a hole saw, though more accurately it ought to be called a hole cutter. This consists of a bar with a cutting blade at one end and a shank to fit a drill chuck. As the drill rotates, the cutting blade cuts a circle. The main advantage of this type is that the blade can slide along the bar, making it adjustable. The disadvantage is that it has quite limited depth, and can only cut drywall, plywood and similar thin sheets.
Hole saw materials
What the hole saw is made of will define the materials it can cut through.
- High carbon steel (HCS) is a relatively low-cost metal used for entry-level hole saw sets. You don't really need anything more if you're working with drywall or softwood.
- Bi-metal is the most popular choice for hole saws. The main body is a flexible steel, which gives good resistance to the harsh pounding these tools can take. The toothed section is made from high speed steel (HSS) which is very hard and gives a sharp edge. In some cases, cobalt is added, making it even harder. M2 and M3 are types of HSS often found in these tools. Bi-metal hole saws will cut through wood, plastics, laminates, aluminum and even thin sheet steel.
- Tungsten carbide tip (TCT) and solid HSS hole saws are good for cutting thicker metal.
- Diamond hole saws are used for cutting glass, tile, concrete, granite, marble and other types of stone. Instead of teeth, these hole saws have a particle coating of silicon carbide (SiC), also known as carborundum – not diamond at all. The thickness, depth and quality of the coating has a big impact on performance and the depth of material they can cut through, so it's important to check before purchasing. Some, for example, are not suitable for concrete.
Other hole saw features
- Most hole saws have slots in the sides that allow the escape of dust and debris which would otherwise build up inside. If you're drilling thick material, it's a good idea to stop occasionally and clear it anyway.
- Tooth pattern will affect cutting efficiency and finish. Large, course teeth provide aggressive cutting. Irregular tooth patterns help stop teeth from getting jammed with powder from drywall or fiberboard. Small, regular teeth should leave a smooth surface. It's similar with the grain size of diamond hole saws – large grains for fast cutting (particularly in coarse materials), small grains for smooth finishes on tile and glass.
- Nickel plating looks good, but serves no real purpose beyond preventing rust.
- The hole saw cuts a plug out of the material, which can get stuck in the body of the saw. It's not usually difficult to remove – the slots allow access for a screwdriver. However, some hole saws incorporate spring mechanisms to eject plugs, which is very convenient.
- Whether choosing a toothed or diamond hole saw, it's vital to check the maximum depth of cut it's capable of. Some are surprisingly short.
"Thick-walled hole saws are usually designed for cutting metal. They will cut wood and other materials, but thin-walled alternatives usually do those jobs better."
STAFF
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Hole saw set prices
Inexpensive: Basic hole saw sets of high carbon steel (HCS) for cutting wallboard or pine paneling can be found for between $15 and $20. You'll find basic metal-cutting HSS hole saw sets for a similar price, but consider spending $10 to $15 more for TCT versions. Entry-level diamond hole saw sets don't cost any more than HCS versions – though depths will be limited, and the range of cuttable materials may be restricted.
Mid-range: Good bi-metal hole saw sets are in the $50 to $90 range, for which you'll get 12 to 15 sizes.
Expensive: A boxed set of heavy-duty diamond saws from a premium brand can be $200 or more, and you might get 8 or 10 sizes.
The main takeaway here is that there's something for every budget – but it pays to buy quality. Better to buy three of four really good pieces than a cheap set of 12, half of which you may never use.
Tips for using hole saws
- If your hole saw is cutting at an angle, you'll end up with an oval hole, not a round one. Patience is important. Let the saw cut, don't try to force it.
- Splintering can be a problem when the hole saw exits out of the material – particularly with wood and plywood. If the resulting hole will be seen from both sides, you can either attach a sacrificial board to the back, or drill half way from one side, then use the pilot hole to line up and complete the cut from the other side.
- If you need to make an existing hole bigger, you'll often find a pilot drill isn't large enough to provide a guide – but cutting without one is almost impossible because of the way a hole saw wanders. If you have a hole saw of the same size to the existing hole, you can 'double up' – attaching that one and the large one on the same arbor, thus benefiting from the guide you need.
- Use water as a lubricant for cutting concrete, stone, granite, etc. Use cooling oil when sawing into metals. They not only keep the blade cool and cutting better, they help disperse debris away from the cut.
- The hex keys that hold hole saw, arbor and pilot drill together can work loose. Often you'll notice a change in sound. Check regularly and tighten if necessary. If it comes apart it can ruin your work.
- Pilot drills typically wear more quickly than the hole saw. They need to be sharp to give you an accurate start. They are cheap and easy to replace, so don't struggle with blunt bits.
FAQ
Q: Should any special safety precautions be taken when using a hole saw?
A: As when using any power tool, always wear eye protection. Hole saws can produce a considerable amount of dust and airborne debris, so a lightweight breathing mask is a good idea.
When the cutting edge of the hole saw itself makes contact, there can be a noticeable torque reaction that can cause the drill to twist in your hands. Make sure you have a firm grip, and wherever possible keep the cutting edge level with the work surface.
If you're working with a corded drill and using water as a coolant, make sure the drill is connected to a GFCI (ground fault circuit interrupter) to prevent electric shock.
Q: Can I use hole saws with any type of drill?
A: You can, but you need to consider the material you are drilling and the size of the hole. A one-inch hole in plywood shouldn't present any problems for a DIY-type cordless drill. A two-inch hole in concrete is a very different proposition. If you have lots of heavy-duty work in hard materials, a powerful Slotted Drive System SDS drill is the obvious choice.
Bear in mind whatever the drill, you should only use rotary, not hammer action. A hole saw is not designed to cut that way, and you'll very likely damage it and possibly deform the hole, too.
Q: What's the difference between an annular cutter and a hole saw?
A: In essence, all hole saws are a type of annular cutter in that they are a ring shape with teeth or cutting material on the edge. Machine tool annular cutters have a much thicker cutting edge and no pilot drill. They are designed for precision engineering work and normally used in lathes or milling machines.
