Skil 21 Pc. Gold Oxide Drill Bit Set

First impressions

I put this Skil 21-piece set through a week of real tasks in the shop: hanging fixtures in thin steel, drilling pilot holes in 3/4-inch oak, opening up holes in aluminum brackets, and general plastic work. My takeaway is that it’s a solid, budget-friendly generalist set with a few thoughtful touches that make day-to-day drilling easier. It won’t replace higher-end cobalt bits for stainless or production work, and quality control isn’t perfect, but for most wood, plastic, and mild steel jobs it gets the job done cleanly—if you use the right speeds and technique.

What you get

• Sizes from 1/16 to 1/2 inch, with duplicates in the smaller, easy-to-snap sizes (two each of 1/16, 5/64, 3/32, 7/64, and 1/8).
• High-speed steel with a gold oxide coating.
• 135-degree split points on 1/8-inch and larger bits.
• Round shanks.
• A metal indexed case with clear markings.

The duplicates in the small sizes are a smart inclusion. Those bits see the most abuse and are the ones you’re most likely to break or dull when you’re rushing a pilot hole.

Build quality and design

The grind on the larger bits in my set looked consistent, and the 135-degree split points were correctly formed, which mattered when I was starting holes on slick, painted sheet metal. The smaller bits (under 1/8 inch) do not have split points, so they’ll skate if you don’t center punch or start at low pressure. The gold oxide coating is not a hard, wear-resistant coating like TiN or TiAlN; think of it as a surface treatment that helps with heat and oil retention, not a miracle shield. Expect it to discolor quickly in steel—that’s normal.

The round shanks fit universally but can spin in a loose keyless chuck on larger diameters if you push hard. Tighten well, or lock down a keyed chuck for the 3/8 and 1/2-inch sizes.

The metal case is better than the typical plastic clamshell. The indexing is clear, sizes are easy to read, and the bits don’t rattle around. The latch isn’t fancy, but it stayed shut bouncing around in my tool bag.

Performance in wood and plastic

In wood, the set did exactly what I want from a general-duty twist bit. In 3/4-inch red oak, the 3/16 through 3/8-inch bits cut cleanly at moderate speed with steady chip ejection. A backer board prevented tear-out on exit, and the split points minimized walking on entry. If you’re used to brad-point bits for crisp hole placement in fine woodworking, you’ll still prefer those for visible work, but for construction lumber, cabinetry carcass work, or general shop tasks, these were just fine.

In plywood and MDF, I had no burning at reasonable speeds and feeds; the coating seemed to shed dust rather than caking up. In plastics (ABS and acrylic), the lips were sharp enough to avoid chipping when I slowed the speed and backed off the feed near breakthrough. A quick tip: for acrylic, grind or stone a very slight negative rake on the cutting lips, or just feather the trigger and let the bit scrape rather than dig to reduce cracking.

Performance in metal

The set is billed for sheet metal and medium-gauge steel, and that lines up with my experience. In 18-gauge mild steel, the 1/8, 1/4, and 3/8-inch bits started accurately with a light center punch and a controlled feed. The 135-degree split point helps reduce walking and generates a shorter, stronger chisel edge—helpful on thin material. With a few drops of cutting oil and sensible speed (around 600–800 RPM for 3/8-inch in mild steel), chips came off in tight curls and the edges stayed crisp for the handful of holes I made.

I did push the 1/2-inch bit through 1/16-inch steel to see how it behaved on a larger opening. It did the job, but it’s much happier if you step up: 1/8 to 1/4 to 3/8 to 1/2. Going straight to 1/2 from a tiny pilot tempts the larger bit to grab and leaves a ragged exit on thin stock. Deburr afterward regardless.

In aluminum, these bits cut quickly and stayed controllable with a dab of paste lube. Keep speeds conservative to avoid galling. I didn’t attempt stainless, and I wouldn’t recommend this set for it; HSS with oxide is not the recipe for a forgiving day in 304.

Heat, wear, and sharpening

After a dozen holes in mild steel and plenty of woodwork, the cutting lips on the mid-range bits still looked tidy. The gold oxide finish wears evenly and shows heat patterns, which I find useful as a visual reminder to slow down. The edges do dull faster in steel than cobalt bits, but that’s expected at this price point.

I did touch up a couple of sizes on a bench grinder. The steel took an edge easily and didn’t burn or crumble when I used a light touch and a cooling dip. On one small bit, I managed to overheat the tip almost instantly with an aggressive grind—it lost edge retention faster than the others afterward. That suggests there can be some variation batch-to-batch, especially on the tiny diameters. The duplicates help you shrug it off and keep moving.

Usability quirks and tips

• Use a center punch. The split points are good, but a quick dimple makes thin metals and laminates go smoother.
• Slow the big bits down. Larger diameters in steel want low RPM and steady feed with oil. If the chips turn blue, you’re too hot.
• Step up on thin metal. It reduces grabbing and gives a rounder, cleaner hole.
• Tighten the chuck hard on the larger bits. Round shanks can spin if the chuck is even slightly oily.
• Back your work. A scrap backer prevents blowout in wood and supports thin sheet as you break through.

Where it falls short

This isn’t a set for stainless, hardened fasteners, or thick structural steel. If that’s your world, cobalt or carbide is the better spend. The smaller bits lacking split points can walk more than you might like if you’re used to premium sets that include it across the board. And while most bits in my set were straight and true, one 1/8-inch bit had a slight wobble. It didn’t ruin a job, but I pulled a duplicate and moved on. That’s a reminder to spin each bit in the chuck once when you first open the case; exchange anything that’s obviously bent.

Who it’s for

• Homeowners and DIYers who need a complete range of common sizes for mixed materials.
• Hobbyists and makers working in wood, plastics, aluminum, and mild steel.
• Pros who want an inexpensive, all-around set to live in a service truck or jobsite box for non-critical drilling.

Who it’s not for: machinists, metal fabricators drilling stainless or tough alloys daily, or anyone expecting brad-point precision in furniture-grade hardwoods.

Value and alternatives

In its price tier, the Skil set earns points for the split-point geometry on the most-used sizes, the useful duplicates, and the metal case. You can find pricier sets with TiN coatings or M35 cobalt that hold an edge longer in steel, but you’ll pay for that longevity. If your workload is mostly wood with occasional mild steel, the economics here make sense. If you frequently open holes in steel plate or tackle stainless, step up to cobalt and keep this set for wood and plastic.

Recommendation

I recommend this Skil set for general-purpose drilling in wood, plastic, aluminum, and mild steel. The 135-degree split points on 1/8-inch and larger bits start cleanly, the assortment covers nearly everything a home shop or jobsite will encounter, and the metal case keeps you organized. You’ll need to respect speeds and use cutting fluid in metal, and there’s some variability in the smallest sizes, but the included duplicates and easy-to-sharpen steel make the occasional hiccup manageable. For the price, it’s a practical, no-drama kit that earns a spot in the toolbox, with the clear caveat that it’s not the right choice for stainless or heavy-duty fabrication.