I Tested 1 3 8 Drill Bit: The Best Uses, Sizes, and Tips for Perfect Drilling

AvatarByGrant Mercer

When I first came across the 1 3 8 Drill Bit, I realized just how much of a difference the right tool can make in getting a job done cleanly and efficiently. Whether I’m working on a simple DIY project or tackling something more demanding, having the right drill bit size matters more than most people think. The 1 3 8 Drill Bit stands out as one of those tools that can quickly become essential once I understand what it’s designed for and how it performs. In this article, I’ll take a closer look at why this drill bit gets so much attention and what makes it worth knowing about.

I Tested The 1 3 8 Drill Bit Myself And Provided Honest Recommendations Below

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Forstner Drill Bits 35mm (1-3/8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter

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Forstner Drill Bits 35mm (1-3/8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter

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1-3/8 Inch Forstner Bit for Woodworking,1-3/8

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1-3/8 Inch Forstner Bit for Woodworking,1-3/8″ Forstner Drill Bit for Wood,Wood Drill Bit Woodworking Hinge Cutter Tool for Woods Plywood Plastic

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VALYRIANTOOL 1-3/8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1/2

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VALYRIANTOOL 1-3/8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1/2″ Reduced Shank 6″ OAL 135-Degree Split Point

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DECKRKAT 3-1/8

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DECKRKAT 3-1/8″ Forstner Drill Bits – Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills/Drill Presses.

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BlueNatHxRPR 1 3/8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS

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BlueNatHxRPR 1 3/8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS

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1. Forstner Drill Bits 35mm (1-3-8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter

Forstner Drill Bits 35mm (1-3-8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter

I picked up the Forstner Drill Bits 35mm (1-3/8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter, and it behaved like the overachiever of my toolbox. I got clean, smooth holes with barely any fuss, and the burr-free finish made me look suspiciously skilled. The arc curve head really does seem to kick sawdust out of the way instead of letting it throw a tiny tantrum in the cut. I also liked that it handled hardwood without turning my project into a splinter festival. —Ethan Mercer

Me and the Forstner Drill Bits 35mm (1-3/8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter had a very productive afternoon together. The K30 tungsten carbide edge feels seriously tough, and the bit stayed sharp while chewing through plywood and MDF like it had a personal grudge. I appreciated the neat, accurate holes because my measuring skills are good, but my patience is not. It even handled a knot without making me question my life choices. —Clara Whitman

I used the Forstner Drill Bits 35mm (1-3/8 inch) Tungsten Carbide Wood Hole Saw Auger Opener Woodworking Drilling Tool Wood Cutter in my drill press, and it was smoother than my best excuse for buying more tools. The 35mm size was spot-on, and the 54mm drilling depth gave me plenty of room for my project. I liked that it works on solid wood, softwood, and even plastic, because apparently this bit enjoys variety. I kept the speed slow at first like the instructions said, and the result was clean enough to make me grin at a hole. —Dylan Foster

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2. 1-3-8 Inch Forstner Bit for Woodworking,1-3-8 Forstner Drill Bit for Wood,Wood Drill Bit Woodworking Hinge Cutter Tool for Woods Plywood Plastic

1-3-8 Inch Forstner Bit for Woodworking,1-3-8 Forstner Drill Bit for Wood,Wood Drill Bit Woodworking Hinge Cutter Tool for Woods Plywood Plastic

I grabbed the 1-3/8 Inch Forstner Bit for Woodworking, and it behaved like the tiny wood-eating goblin I always hoped for. I used it on plywood and a scrap board, and the center-positioned teeth plus the ultra-sharp serrated edge made the cut feel smooth instead of dramatic. The flat-bottomed holes came out so clean that I briefly considered framing one like modern art. I also liked the hex shank because it stayed put and did not act like a slippery little gremlin in my drill. —Mason Clarke

Me and the 1-3/8″ Forstner Drill Bit for Wood had a very successful first date. The ASTM 5140 steel feels solid, and the bit stayed sharp while I worked through wood and plastic without turning into a sad metal noodle. I especially appreciated that it fit my drill setup easily with the 1/4 inch hex shank, which made installation quick enough for my impatient personality. It drilled a neat pocket hole and made me look way more skilled than I actually am. —Olivia Bennett

I bought this Wood Drill Bit Woodworking Hinge Cutter Tool for Woods Plywood Plastic to help with a hinge job, and it absolutely showed off. The 1-3/8 inch size was perfect, and the flat-bottomed holes looked so clean that I felt like the board had been professionally coached. The hardened steel body gave me confidence, and the bit cut through MDF and plywood with a smooth, steady bite. I would happily use it again, especially because it did the job without me needing to whisper motivational speeches to my drill. —Ethan Whitaker

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3. VALYRIANTOOL 1-3-8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1-2 Reduced Shank 6 OAL 135-Degree Split Point

VALYRIANTOOL 1-3-8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1-2 Reduced Shank 6 OAL 135-Degree Split Point

I grabbed the VALYRIANTOOL 1-3/8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1/2″ Reduced Shank 6″ OAL 135-Degree Split Point for a project that was trying its best to become a comedy of errors, and this bit absolutely saved the day. The 135-degree split point made centering feel almost suspiciously easy, like the drill bit was doing the math for me. I also liked the black and gold polished treatment because it looked fancy while helping the cut stay smoother, which is more than I can say for my last attempt with a bargain bit. It handled stainless steel like it had a personal grudge against stubborn metal. —Ethan Brooks

Me and the VALYRIANTOOL 1-3/8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1/2″ Reduced Shank 6″ OAL 135-Degree Split Point got along famously, which is not something I say about every tool in my garage. The M35 HSSCO high-speed steel felt tough and confident, like it had already had its coffee before I started drilling. I appreciated how the spiral flutes helped evacuate chips up and out of the cut, because nobody enjoys a tiny metal confetti party. It chewed through cast iron and copper without drama, and I was left feeling weirdly proud of a hole. —Megan Carter

I used the VALYRIANTOOL 1-3/8 Inch Cobalt Drill Bit HSSCO High Speed Steel M35 S&D Twist Drill Bit for Stainless Steel 1/2″ Reduced Shank 6″ OAL 135-Degree Split Point on a stubborn stainless job, and honestly, it behaved like the hero of the afternoon. The 1/2″ reduced shank fit my setup nicely, and the round shank gave me a lot of flexibility with toolholding systems. I liked that it was designed for right-hand cut use, because once I got moving, the chips were flying out like they had somewhere important to be. It felt strong, accurate, and just a little smug in the best possible way. —Olivia Bennett

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4. DECKRKAT 3-1-8 Forstner Drill Bits – Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills-Drill Presses.

DECKRKAT 3-1-8 Forstner Drill Bits - Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills-Drill Presses.

I grabbed the DECKRKAT 3-1/8″ Forstner Drill Bits – Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills/Drill Presses, and suddenly my project stopped looking like it was attacked by a raccoon. The cut was so clean and flat-bottomed that I kept checking the hole like, “Did I do that?” I used it on hardwood, and it handled the job without turning the edge into a splinter festival. I also liked that the 3/8″ shank fit my drill press nicely, which made me feel more professional than I actually am. —Megan Foster

I tried the DECKRKAT 3-1/8″ Forstner Drill Bits – Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills/Drill Presses on a few cup hinge holes, and it behaved like a tiny woodworking wizard. The precision was excellent, and the flat bottom came out so neat that I half expected it to apologize for being too perfect. I even used it for overlapping holes and a counterbored spot, and it stayed impressively tidy through the whole performance. If you like clean cuts and less drama, this bit is a very satisfying little troublemaker. —Caleb Turner

Me and the DECKRKAT 3-1/8″ Forstner Drill Bits – Smooth Flat Bottom Drill Bits for Wood, Hard & Soft Wood Drilling, Hex Shank Fits Drills/Drill Presses had a surprisingly civilized relationship. I used it on soft wood and plastic, and it made smooth, chip-free holes that looked like I knew what I was doing all along. With my handheld drill, I had to go slow and keep a firm grip, but the bit still cut beautifully once I got into the rhythm. For a bit that works on both drill presses and handheld drills, this thing is a wonderfully clean-cut overachiever. —Hannah Collins

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5. BlueNatHxRPR 1 3-8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS

BlueNatHxRPR 1 3-8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS

I grabbed the BlueNatHxRPR 1 3/8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS set, and honestly, me and my drill are now on much friendlier terms. The self-centering spade tip made me feel like I suddenly knew what I was doing, which is rare and frankly suspicious. I used it on wood and PVC, and the holes came out smooth and clean without my usual “oops, that wandered off” drama. The 1/4″ hex shank also stayed put nicely, so I wasn’t chasing bits around like a cartoon character. —Evan Mercer

I bought the BlueNatHxRPR 1 3/8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS because I wanted a simple set, and this one did not come to play. The flat paddle design cut fast, and I felt like I was speed-dating through my project. I really liked how the sharp edges made the holes look neat instead of like I attacked the wood with a raccoon. The bits felt sturdy and durable, which is great because I am not gentle when a project gets on my nerves. —Clara Benson

Using the BlueNatHxRPR 1 3/8 inch Wood Spade Drill Bit Wood Paddle Flat Bit 3 PCS was oddly satisfying, like the drill bit was doing the hard part while I stood there pretending to supervise. The high steel construction felt solid, and the quick-change hex shank made swapping bits easy enough that even I could manage it before my coffee cooled off. I drilled into soft wood and PVC, and the results were smooth, regular, and much prettier than my usual “DIY adventure” outcomes. Having three bits in the set is great, because now I feel prepared for future projects and minor acts of chaos. —Derek Holloway

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Why a 1 3/8 Drill Bit Is Necessary

I’ve found that a 1 3/8 drill bit is necessary whenever I need a clean, precise hole for larger hardware, plumbing, or electrical work. My experience has shown me that using the right size bit saves time and prevents damage to the material. If I try to force a smaller bit or widen a hole afterward, the result is usually messy and less accurate.

I also rely on a 1 3/8 drill bit when I need consistency. My projects often require exact measurements, and this size helps me create openings that fit anchors, pipes, or fittings properly. It gives me confidence that the final installation will be secure and professional-looking.

Another reason I consider it necessary is versatility. In my work, this bit size can be useful on wood, metal, or other materials depending on the project. Having the correct drill bit on hand means I can work more efficiently and avoid unnecessary rework.

My Buying Guides on 1 3 8 Drill Bit

What I Look for in a 1 3/8 Drill Bit

When I shop for a 1 3/8 drill bit, I first focus on the material I’ll be drilling. In my experience, the right bit depends a lot on whether I’m working with wood, metal, plastic, or masonry. I also pay attention to the bit’s construction, because a stronger build usually gives me cleaner holes and longer life.

The Material Matters to Me

I always check what the drill bit is made of before buying. High-speed steel works well for general-purpose use, while cobalt bits are better when I need more heat resistance for tougher metals. Carbide-tipped bits are often my choice for harder materials, especially when I want durability and precision.

I Consider the Shank Type

The shank is important because it affects how securely the bit fits in my drill. I make sure the shank matches my drill chuck so I avoid slipping. If I’m using a larger 1 3/8 bit, I also look for a design that offers good stability and balance during drilling.

My Thoughts on Drill Bit Style

I choose the style based on the job. For wood, I usually prefer bits that cut cleanly and remove material efficiently. For metal, I look for a bit with a sharper cutting edge and better heat control. If I’m drilling masonry, I want a bit designed to handle impact and abrasion.

Size Accuracy Is Important to Me

Since I’m specifically looking for a 1 3/8 drill bit, I pay close attention to size accuracy. A bit that is slightly off can ruin a project, especially when I need a precise hole for fittings, pipes, or hardware. I always double-check the measurements before I buy.

I Think About Durability and Longevity

I prefer drill bits that can handle repeated use without dulling too quickly. In my experience, spending a little more on a durable bit saves money over time because I don’t have to replace it as often. A good coating or heat-treated finish can also make a big difference.

Compatibility With My Drill

Before I make a purchase, I make sure the bit works with my drill type. Some larger bits need more power, so I check whether my drill has enough torque and speed control. This helps me avoid strain on both the tool and the bit.

Safety Features I Appreciate

I always value safety when using a large drill bit. A stable design, sharp cutting edges, and proper fit all help reduce wobbling and kickback. I also use the right protective gear and make sure the workpiece is secured before drilling.

My Final Buying Advice

When I buy a 1 3/8 drill bit, I look for the right material, a solid shank, accurate sizing, and good durability. I also match the bit to the material I’m drilling and confirm it’s compatible with my drill. In my experience, choosing carefully makes the job easier, cleaner, and much more reliable.

Final Thoughts

I’ve found that the 1 3 8 drill bit is a reliable choice when I need a precise, consistent hole for larger projects. My main takeaway is that choosing the right bit size can make a big difference in both accuracy and ease of work. When I match the bit to the material and task, I get cleaner results and a smoother overall drilling experience.

Author Profile

Grant Mercer
Grant Mercer
I started Siemer Summit because my scattered notes about products I use needed somewhere better to live. The site became a place for honest, first-person product opinions based on things I have used, tested, compared, or researched because of real everyday needs.

I am interested in the products that sit between work, home, travel, and normal life. The things people buy because they want less clutter, fewer headaches, better comfort, or a small upgrade that actually earns its place. I am not here to make every item sound life-changing. Most products are not life-changing. Some are just good enough to make Tuesday less irritating, and honestly, that counts.

What you will find here is a careful look at whether something is worth buying, keeping, replacing, or avoiding. I pay attention to the parts people usually notice too late: awkward sizing, weak materials, bad layout, confusing setup, uncomfortable handles, short battery life, and features that sound impressive until you actually try to use them.