THINKWORK W6139-HSS 5-Piece HSS Step Drill Bit Set

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Product guide

THINKWORK W6139-HSS 5-Piece HSS Step Drill Bit Set

Piece: The THINKWORK W6139-HSS step drill bit set is listed as five HSS bits with four spiral flutes and TiN coating. Its stated ranges cover several stepped hole sizes, but the listing gives conflicting kit details, so confirm the exact bits and case before ordering.

At a glance

Four-flute spiral design and laser-marked step sizes are presented for controlled hole enlargement and size selection.
The manufacturer lists five bit ranges from 1/8" to 1-3/8" overall, with a different number of steps on each bit.
The listing describes use on thin metal and wood, and also names aluminum, copper, iron, carbon steel and plastic.

Price

$27.99Save 12%

Reference price: ~~$31.97~~

Price checked: Nov 13, 2026

View offer Ahead of Black FridayExplore the selection

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Pros and cons

Pros

Five stated size ranges cover a variety of hole diameters, including a bit reaching 1-3/8".
Laser-marked sizes are intended to make step selection easier while working.
HSS construction and a TiN finish are specified.

Technical specifications

12 specifications

Identity
Brand	THINKWORK
Model	W6139-HSS Step Drill Bits

Dimensions and installation
Dimensions listed	6 x 1.5 x 4 inches
Shank type	Straight

Materials and protection
Material listed	High Speed Steel (HSS)
Finish	Titanium Nitride

Cutting design and applications
Cutting diameter	1.38 inches
Minimum bore diameter	4.76 millimeters
Flute type	Spiral
Number of flutes	4
Point style	Step Point
Surface recommendation	Metal, Wood, Plastic

What to know before buying

Listing details to confirm

The listing conflicts on kit details: its title says 59 steps, the five individual ranges add up to 59 steps, but another item highlight claims sizes from 1/8" to 1-3/8" without explaining the count. Shank descriptions also vary between a straight shank and 1/4" plus 3/8" shanks. The case is claimed in feature copy but absent from the explicit contents list. Confirm the selected listing's exact sizes, shanks and case before buying.

What’s in the box

5 step drill bitsIncluded
Storage caseCheck selected pack

Check which accessories are included in your selected pack before buying.

Who is it for?

A good fit for

DIYers or maintenance users enlarging holes in thin sheet metal, wood or plastic who want multiple step ranges in one kit.
Buyers who prefer size markings on the bits to identify the intended hole diameter.

Less suited to

Buyers who need a confirmed case or a particular shank size without first checking the selected listing.
Users who need dependable performance for demanding or repeated work, given customer reports of dulling and breakage.

THINKWORK W6139-HSS 5-Piece HSS Step Drill Bit Set · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.4 / 5 · 612 ratings

5 stars71%71%
4 stars14%14%
3 stars7%7%
2 stars1%1%
1 star7%7%

Customer feedback is generally positive about quality, functionality and cutting performance, including reported use in steel, aluminum and hard metal. Feedback on sharpness is mixed, with some finding the bits sharp and others reporting quick dulling. Durability is a notable concern, including reports of breakage at the second step. For buyers considering the listed HSS, four-flute set for metal or other stated materials, those reports make workload and expected service life important trade-offs.

Positive themes

Customers report good functionality and cutting performance.
Some customers describe the bits as sharp and report use in steel, aluminum and hard metal.
Customers express positive views about quality and value.

Negative themes

Customers report durability concerns, including breakage at the second step.

Mixed feedback

Sharpness feedback is mixed, with reports of both sharp cutting and quick dulling.
Material compatibility is not uniformly reported.

Frequently asked questions

How many bits and step sizes are claimed?

The feature description claims five bits with ranges of 3/16"-1/2" (6 steps), 1/8"-1/2" (13 steps), 1/4"-3/4" (9 steps), 3/16"-7/8" (12 steps), and 3/16"-1-3/8" (19 steps). Together these total 59 steps, while other listing details are inconsistent, so check the selected listing.

What materials does the listing recommend?

The surface recommendation names metal, wood and plastic. Feature copy also names aluminum, copper, iron and carbon steel, and describes drilling thin sheet metal and wood.

Is a storage case included?

The feature description claims a blow-molded case, but the explicit contents list only says “step drill 5pcs.” Case inclusion is therefore uncertain. Confirm the selected listing.

Are the shanks 1/4 inch or 3/8 inch?

The listing is inconsistent: it specifies a straight shank in one detail field and claims 1/4" plus 3/8" shanks in another. Check the listing for the exact shank configuration.