- Cutting square holes?
- Best square hole mortising drill bits
- Why is Delta 17-924 the best square hole drill bit?
- Delta 17-924 vs. Powermatic 1791096
- Picking out the best square hole drill bits
- The strongest material for square hole drill bits
- How do square hole drill bits work?
- Tips for handling square hole drill bits
- What other tools can cut square holes?
- How fast can you drill with a square hole drill bit?
- Comparison of square hole mortising drill bits
- Our verdict: the most precise square hole cutter
- Delta 17-924
Last updated on October 11, 2025 10:39 am
Cutting square holes?
According to Aaron Barnett of BangingToolbox: The best square-hole drill sets have at least 4 different sizes for different jobs.
They should universally fit in a drill press, or mortising machines that operate with a hammering function that drives the chisel corner edges down as the drill bores out the bulk of the hole.
These bits are essential if you want to do fast, repetitive square cuts in wood.
I was truly blown away when I discovered it’s possible to drill square holes. Not even my wood router can do this.
Best square hole mortising drill bits
#1 Best square drill bit [Kit]
Delta 17-924, 4pcs, HSS, Mortising chisel attachment set
- Includes four of the most commonly used chisel and bit sets: ¼”, ⁵⁄₁₆”, ⅜”, and ½”.
- Mounts and dismounts easily.
- It cuts nice and clean holes in hardwoods.
- Fits a wide variety of drill presses.
- The fence can be challenging to set up.
- The screws could be more precise and robust.
#2 Best mortise machine square drill bits
SaferCCTV ZXL3193-4 7pcs, HSS, Mortising square drill bits
- Provides good wear resistance and durability for mortising wood.
- It can be used with different brands of mortise drills.
- Makes immaculate cuts with smooth walls.
- Flexibility for different mortising widths.
- Quality and precision issues.
#3 Good fitting mortising square drill bits
Woodstock D2845 4pcs, HSS, Mortising drill bits
- Comes in a wide range of diameters, from ½” to 4 ¼”.
- Fits most mortising attachments with collars measuring ¾”.
- Comes with a plastic storage case.
- Needs to be sharpened out of the box for best results.
#4 Nice value square drill bits
ArtisanShow 6pcs, HSS, Mortising drill bits
- Fits most brands of mortising machines and drill presses.
- Made of superior quality, heat-treated steel.
- It comes with six drill bits in different slot diameters to accommodate a range of applications.
- Better suited for light duties.
#5 Chip-extracting mortising drill bits
CSLU 4pcs, HSS, Mortising drill bits
- Works with most types of mortising machines and drill press attachments.
- Made of excellent quality steel with a hardness rating of HRC 48~50.
- Features a geometric flute design for optimum chip extraction.
- You will need to hone these beforehand for the best results.
#6 Easy-drilling square hole drill bits
Driak 4pcs, HSS, Mortising drill bits
- Creates clean holes consistently with minimal effort.
- Works equally well with hard or softwood.
- Removes wood chips efficiently.
- The build quality could be improved.
#7 More wood-friendly square mortising drill bits
Amena 4pcs, HSS, Mortising drill bits
- Cuts through most woods quickly and easily.
- Works with a wide range of mortising machines and drill presses.
- Made of superior quality heat-treated steel with an HRC48 to 50 rating.
#8 Corner-penetrating mortising drill bits
Max-Craft 7pcs, CRV-HCS, Mortising drill bits
- Drilling tips and cutting corners are designed for fast penetration and clean drilling.
- Consistently produces clean square holes with smooth sides.
- Better suited for shallow cuts.
- Doesn’t seem as durable as other drill bits.
#9 Heat-processed mortising square drill bits
New Hope 5pcs, HSS, Mortising drill bits
- Made of heat-processed steel for maximum durability.
- Comes in a range of standard mortise sizes.
- Works with most mortising and bench drilling machines.
- They may need lubricating before use.
#10 HSS square mortising drill bits
Rowiz 3pcs, HSS, Mortising drill bits
- Made from high-carbon steel.
- Combines tough drill bits with precision sharpened chisel edges.
- Comes in three diameters ranging from 14 mm to 19 mm.
Why is Delta 17-924 the best square hole drill bit?
If you’ve ever wanted to drill a square hole, the Delta 17-924 square hole drill bits offer pro-quality at a price that won’t break the bank.
The set consists of four of the most commonly used chisel and bit sizes, including ¼”, ⁵⁄₁₆,” ⅜,” and ½.” These options cover you for pretty much any size mortise that you need to cut.
The 17-924 will work with almost any type of drill press on the market, with quill diameters ranging from 38 millimeters to 66 millimeters.
It works flawlessly on most hardwoods and does a great job at cutting mortises into softer woods such as pine.
If you don’t need a dedicated mortising machine, the Delta 17-924 is an excellent alternative that gives you some of the best drill bits on the market.
Delta 17-924 vs. Powermatic 1791096
Delta 17-924
The Delta 17-924 and the Powermatic 1791096 are the two best options if you need a premium quality set of square hole drill bits.
Both offer excellent bang for the buck, and you really can’t go wrong regardless of which one you choose.
The 17-924 set is the one to go for if versatility is your main priority. The different sizes span a broad range and will let you cut mortises in various widths.
Powermatic 1791096
The Powermatic 1791096 is no slouch, either. Boasting premium quality carbon steel, these are some of the most durable square drill bits for wood.
Their ability to make clean cuts is impressive, and I recommend having a pack of these handy when doing a lot of mortise work, and you need to drill square holes in wood quickly.
Picking out the best square hole drill bits
#1 Best square hole mortising chisel attachment set
The Delta 17-924 kit provides almost everything you need to cut clean and smooth mortises.
With the right drill press, these square hole cutters can create pro-looking square holes with minimal effort.
The kit comes with four chisels and bits in the following sizes: ¼”, ⁵⁄₁₆,” ⅜,” and ½.” These bits are ideal for the Delta 18-900L drill press, but they will work just as well with the 21313 and 21317 drill presses.
You get a smart-looking carrying case for easy storage and transport of your square drill bits for the price.
Unless you make furniture full time–in which case you would probably need a dedicated mortising machine–the Delta 17-924 kit is an excellent addition to your toolbox.
#1 Finest value square hole mortising drill bit set
If you’re looking for a lower-priced alternative that doesn’t compromise quality and performance, the ArtisanShow 6pcs, HSS, and Mortising chisel bits are for you.
These bits are made to work with almost any brand of mortising machine on the market, and they can turn any drill press into a very capable mortise cutter.
The ArtisanShow set comes in a variety of diameters, from 6.5 mm to 19 mm. Each bit is made from heat-treated steel for maximum durability and tested to the most rigorous quality control standards.
If you need a fairly cheap but dependable set of drill bits for construction, renovation, and DIY work, the ArtisanShow set is worth looking into.
The strongest material for square hole drill bits
The best square hole drill bits are made of tough high-grade steel. Some bits are made from cold-forged steel combined with a black oxide finish that prevents corrosion, resulting in longer usable life.
Additionally, there are square hole drill bits for metal that are made of tungsten carbide steel. This material is supposedly three times more durable than carbide steel.
How do square hole drill bits work?
Square hole drill bits are used with mortising machines and drill presses. They allow you to cut square holes into wood.
Square hole drill bits consist of an auger-style bit housed in a hollow square with sharp chisel edges. The auger bit first cuts a round hole into the workpiece, and then the chisel edge cuts out the sides of the hole to make it square.
For information on how to cut circular holes in wood click here.
Tips for handling square hole drill bits
- Before you begin drilling a square hole, decide how wide you want your square hole or mortise. You should select a drill bit with a diameter equal to the intended width of your desired hole size.
- Once you have selected the proper drill bit and mounted it to your drill press or mortising machine, set the depth stop to your desired depth. It’s always necessary to mark the mortise position on the workpiece with a pencil before you begin drilling.
- It is important to use the right amount of pressure according to the material you are drilling into. If you don’t press down hard enough, the drill bit won’t bite into the material. It is better to press down just a little bit too hard instead of not pressing down hard enough.
What other tools can cut square holes?
You can cut square holes into wood using a router and a jigsaw or drill with beveled chisels.
To do this, you will need to drill a hole into the inner side of the square you mark off for the hole. Here’s our chisel using guide.
You then use a jigsaw tool to cut away at the hole you’ve just drilled to make it square. You can finish off with a sander to smooth out the edges of the hole.
For information on the best cordless jigsaws see what I have to say here.
If all you have is a drill and a chisel, you can cut out a square hole with a bit of work. Again, this requires drilling a pilot hole into the workpiece with your cordless drill.
Afterward, you can carve out the sides of the hole to make it square.
Or, you can use a rasp, although this is considerably more difficult compared to using other tools. Using a rasp requires that you have access to both sides of the workpiece, which isn’t always feasible.
Here are more detailed ways to cut a square hole.
How fast can you drill with a square hole drill bit?
Probably the most time-consuming part of using a square hole drill bit is setting it up for the first time. After you get used to doing it, though, you can attach your drill bit to your drill press in only a few minutes.
After you have it set up, drilling a square hole will only take you as much time as drilling any other hole.
Comparison of square hole mortising drill bits
| Delta 17-924
| SaferCCTV ZXL3193-4
| Woodstock D2845
| ArtisanShow
| CSLU
| Driak
| Amena
| Max-Craft
| New Hope
| Rowiz
| |
|---|---|---|---|---|---|---|---|---|---|---|
| Verdict: | #1 Square hole drill bits as a kit | Finest value with 6pc set | ||||||||
| Pieces: | 4 pcs | 7 pcs | 4 pcs | 6 pcs | 4 pcs | 4 pcs | 4 pcs | 7 pcs | 5 pcs | 3 pcs |
| Sizes: | 1/4 in- 1/2 in | 1/4 in- 1/2 in | 1/4 in- 1/2 in | 1/4 in-5/8 in | 1/4 in-1/2 in | 1/4 in-1/2 in | 1/4 in-1/2 in | 1/4 in-3/4 in | 1/4 in-5/8 in | 9/16 in-3/4 in |
| Hardness: | HRC 48-50 | HRC 56 | HRC 48-50 | HRC 48-50 | HRC 48-50 | HRC 56 | HRC 48-50 | HRC 48-51 | HRC 48-50 | HRC 48-50 |
| Material: | High-speed steel | High speed steel | High speed steel | High speed steel | High speed steel | High speed steel | High speed steel | CRV-High carbon steel | High speed steel | High carbon steel |
Our verdict: the most precise square hole cutter
The Delta 17-924 offers professional quality mortising attributes at a very reasonable price. It mounts easily on benchtop drill presses and can be dismounted quickly as well.
They are an excellent accessory for cutting out square holes in hardwood, as a cheaper alternative to a dedicated mortising machine while still giving you quality results.
Now that you’ve found out the best way to drill a square hole using a square hole drill bit, you might want to check out the best drill bits for drilling circle holes.
Delta 17-924
What can you get with Delta 17-924?
- Choose from the common chisel and bit sets of various sizes ¼”, ⁵⁄₁₆,” ⅜,” and ½.”
- Change chisel bits easily.
- Precise cuts even in hardwoods.
- Bits can fit universally in drill press and mortising machines.
Delta 17-924 limitations:
- Setting up a fence can be a challenge.
#1 Best square hole mortising drill bits attachment set
Frequently Asked Questions
Can I use a power drill to attach a mortising attachment?
It's not a good idea. Mortising drill attachments only work for drill bits better.
I only have a power drill, can I use it to make a square hole?
Yes. You can use it to drill a pilot hole and utilize a woodworking chisel to cut square holes.
Other tools that can cut other shapes and square holes?
If you're looking for a much more versatile wood cutter, your best bet would be a wood router.
