Milwaukee Red Helix Cobalt Drill Bit Set Review (29-Piece)
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Quick verdict: the Milwaukee 29-piece Cobalt Red Helix set is a strong choice for anyone who drills stainless, hardened and other tough steels. It covers 1/16 to 1/2 in in 1/64 in steps, uses cobalt steel that keeps its hardness at high temperatures, and has a 135° split point that starts without walking. Milwaukee’s Red Helix flute design helps clear chips. It costs more than a TiN set, but in hard metals it lasts far longer.
Best cobalt set for metal
Milwaukee 29 Pc. Cobalt Red Helix Metal Drill Bit Set
★★★★½ 4.5 / 5
- 29 bits, 1/16–1/2 in by 64ths
- Cobalt steel for heat resistance
- 135° split point
- Metal case
Our keyword research showed that “best drill bits for stainless steel” and related searches bring the most engaged readers to this site. In that guide we recommend cobalt bits for good reason: stainless work-hardens and generates heat, and ordinary HSS bits dull quickly. The Milwaukee Red Helix set is one of the most popular cobalt sets on Amazon.
How We Reviewed the Milwaukee Red Helix Cobalt set
We compared the Milwaukee Red Helix Cobalt set against the specs and features that matter for this type of tool, using the manufacturer’s published specifications, the current Amazon listing data, and the same technical standards we use in our drilling guides. We didn’t receive a free sample, and the score reflects value for the buyer, not commission. See our editorial policy for how we write reviews.
Specifications
| Specification | Milwaukee Red Helix Cobalt 29-Piece |
|---|---|
| Pieces | 29 |
| Sizes | 1/16 in to 1/2 in, in 1/64 in steps |
| Material | Cobalt steel |
| Point | 135° split point |
| Flute | Red Helix variable flute design for chip removal |
| Case | Metal index case |
| Weight (listing) | About 2.9 lb |
| Best for | Stainless, hardened steel, cast iron, tough alloys |
What We Like
Cobalt keeps its edge in heat
Cobalt steel stays hard at temperatures that soften standard HSS. That’s why it lasts longer in stainless, where heat builds fast. Our how to drill stainless steel guide explains why heat is the main enemy.
135° split point
The flatter 135° point is stronger than 118°, and the split point starts without a pilot hole or center punch on most surfaces.
Full 64ths index
With every 1/64 in step from 1/16 to 1/2 in, you have most fractional tap drills and clearance holes. For example, 13/64 in for 1/4-20 and 5/16 in for 3/8-16 (see our tap drill size chart).
Solid metal case
The metal index keeps bits sorted and stands up to shop life.
What We Don’t Like
More expensive than HSS/TiN sets
You pay for cobalt. If you mostly drill wood, it’s not worth it.
More brittle
Cobalt is harder but more brittle than HSS. Small bits can snap if the drill wobbles or you side-load them.
Not for masonry
Use carbide-tipped masonry bits for concrete and brick.
Pros and Cons
| Pros | Cons |
|---|---|
| Cobalt holds hardness in heat | Higher price |
| 135° split point | More brittle than HSS |
| Full 1/64 in index | Overkill for wood |
| Metal case | Not for masonry |
| Resharpenable |
How to Get the Most From Cobalt Bits
- Slow down. Use low speed and steady pressure in stainless.
- Use cutting fluid. It cools the edge and extends life.
- Keep it cutting. Don’t let the bit rub; rubbing work-hardens stainless.
- Clamp the work. A drill press or clamped part reduces snapping small bits.
- Resharpen at 135°. A Drill Doctor 750X or 500X keeps the split point.
Red Helix Cobalt vs DEWALT DW1361
| Feature | Milwaukee Red Helix Cobalt | DEWALT DW1361 |
|---|---|---|
| Material | Cobalt | HSS + TiN coating |
| Pieces | 29 | 21 |
| Point | 135° split | Pilot Point |
| Best for | Stainless and hard steel | General purpose |
| Amazon | Red Helix 29-pc | DW1361 |
See our DEWALT DW1361 review for a general-purpose alternative.
Who Should Buy It?
- Welders, fabricators and maintenance techs.
- DIYers who drill stainless, truck frames or hardened parts.
- Anyone tired of burning through HSS bits in steel.
Cobalt vs Titanium vs Black Oxide
| Bit type | What it is | Best for |
|---|---|---|
| Black oxide HSS | HSS with a thin oxide finish | Wood, plastic, light metal on a budget |
| Titanium (TiN) coated | HSS with a hard TiN surface coating | General purpose, longer life than black oxide |
| Cobalt (M35/M42) | Steel alloy with cobalt throughout | Stainless, hardened steel, cast iron |
| Carbide | Very hard, brittle | Production machining, hardened materials with rigid setups |
Because the cobalt runs through the whole bit, resharpening doesn’t remove its benefit. That’s a big advantage over coated bits.
Recommended Speeds in Stainless Steel
| Bit size | Starting speed in stainless |
|---|---|
| 1/8 in | About 1,000 rpm |
| 1/4 in | About 500 rpm |
| 3/8 in | About 350 rpm |
| 1/2 in | About 250 rpm |
These are starting points. If the chips come out blue or the bit squeals, slow down further and add more cutting fluid. Steady pressure is just as important: a bit that rubs instead of cutting will work-harden the surface.
Common Problems and Fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Bit stops cutting in stainless | Surface work-hardened by rubbing | Use more pressure and lower speed, re-sharpen if dull |
| Small bit snaps | Brittle cobalt and side load | Use a drill press or clamp the work |
| Bit walks | Drilling on a curved surface | Center punch first even with a split point |
| Edge chips | Too much speed, interrupted cut | Slow down and keep feed steady |
Buying Checklist
- Drill stainless, truck frames, hardened bolts or cast iron? Get cobalt.
- Mostly wood and plastic? A TiN or HSS set is cheaper and fine.
- Own a drill press? Cobalt bits last longest in a rigid setup.
- Want to keep them sharp? Plan for a 135° capable sharpener.
Frequently Asked Questions
5 quick answers from our editors
01What sizes are in the Milwaukee 29-piece cobalt set?
1/16 in to 1/2 in, in 1/64 in steps.
02Is cobalt better than titanium for stainless?
Yes. Cobalt keeps its hardness at high temperature, while a TiN coating is only a thin surface layer on HSS.
03What point angle are Red Helix cobalt bits?
135° split point.
04Can I sharpen cobalt bits?
Yes, with a diamond wheel sharpener or a bench grinder.
05Are cobalt bits good for wood?
They work, but it’s a waste of money. Use HSS or brad-point bits for wood.
Bottom Line
The Milwaukee Red Helix Cobalt 29-piece set is a serious metal-drilling kit. Cobalt steel, a 135° split point and a full 64ths index make it ideal for stainless and hardened steel. If you drill metal often, it’s well worth the extra cost.
Check the Milwaukee Red Helix Cobalt Set Price on Amazon
As an Amazon Associate, WellableMachine earns from qualifying purchases. Product details come from the manufacturer and Amazon and may change. Check the Amazon listing for the current price and availability. Background: drill bit materials and the official Milwaukee site.
