IRWIN Tools FAQ: Left Hand Drill Bits, Screwdriver Sets, and Mechanics Tool Sets Worth Buying

I manage tool purchasing for a 40-person industrial maintenance company, and I've tracked about $40,000 a year in hand tools and accessories for the last eight years. Every order goes into our cost tracking system. I don't pick tools based on how they look in a catalog photo. I pick them based on what breaks, what doesn't, and what the crew can actually work with.

When I first took over this role, I figured name-brand hand tools were all pretty much the same. Pick the vendor with the best discount and move on, right? A couple of expensive failures later, I learned that total cost of ownership matters just as much for a screwdriver as it does for a $20,000 machine. These are the IRWIN questions I hear most often from our own leads and from other buyers.

What does IRWIN Industrial Tools make?

IRWIN Industrial Tools is broader than most people expect. They make hand tools and power tool accessories: drill bits, screw extractors, screwdrivers, wrenches, sockets, saw blades, and locking pliers, including the original Vise-Grip design. Quick-Grip clamps also carry the family name. If you're only picturing one category, you're missing most of the catalog.

From my side of the desk, the width matters. I can consolidate one purchase order with IRWIN clamps, bits, and screwdrivers instead of juggling four vendors. That cuts shipping cost and invoice processing time. They're not a do-everything specialist, but for the basics a maintenance crew uses daily, they're a solid workhorse brand.

Are IRWIN left hand drill bits actually worth the extra cost?

I used to skip left hand drill bits entirely. They look like ordinary twist bits, they cost more, and I figured our techs could just use a right-hand bit plus a screw extractor when a bolt snapped. That's the oversimplified version, and it ignores how often a left hand bit solves the problem by itself.

Here's the practical difference. A left hand drill bit spins counterclockwise. When you drill into a snapped bolt, the cutting action sometimes catches the broken piece and threads it out before you need an extractor. It won't work every time, and anyone who says otherwise is overselling it. But when it works, you save an hour of extraction work and a lot of foul language.

I changed my mind about these in 2023, after a sheared bolt cost us half a shift. Since then, every maintenance truck carries a small set of IRWIN left hand drill bits. The sets run, if I remember right, somewhere in the $25 to $45 range depending on size. Compared with the cost of downtime, that's a no-brainer.

What makes the IRWIN extra heavy duty screwdriver set extra heavy duty?

Honestly? I assumed the label was marketing. If you've been buying tools for a while, you've seen the phrase on products that wouldn't survive a week of real use.

There is, however, a physical difference you can feel. Put an IRWIN extra heavy duty screwdriver set next to a basic set. The handles are chunkier, the bars are thicker, and the whole design is about applying more torque before the tool fails. That doesn't mean indestructible. No screwdriver is indestructible. It means the failure point is a lot further down the road.

The buying math works out if your crew actually leans on screwdrivers, which is a technical term my team refuses to let me put in official reports. A $15 set that strips after a few hard jobs is not a bargain when downtime costs $180 an hour. The IRWIN extra heavy duty screwdriver set costs more up front, but it survives the jobs that make money.

How should you evaluate a mechanics tool set like cmmt12126?

The mechanics tool set cmmt12126 keeps showing up in search queries from people comparing large mechanics kits. Maybe you're comparing it with an IRWIN mechanics set. I can't tell you which one wins without knowing what you work on, but I can tell you how I compare them.

First, socket sizes that match your actual work. A huge piece count sounds impressive until you realize you mainly need 10 mm, 13 mm, and 1/2 inch sockets in both shallow and deep versions. Second, ratchet quality. A ratchet that skips under load is worse than no ratchet at all, because it rounds off fasteners. Third, replacement parts. If you have to send a broken tool back and wait a week, the set is not saving you money.

When I compare IRWIN mechanics kits with popular sets like the cmmt12126, I ask the same three questions. Buy around your fastener mix, not around the total piece count. That's the difference between buying a tool set and buying a drawer full of things you'll never use.

How do you put a drill bit in an impact driver?

The short answer is that you don't push a standard round-shank drill bit into an impact driver. Impact drivers use a spring-loaded collet that only accepts 1/4 inch hex-shank bits. A round-shank twist bit won't lock in, and forcing it is a good way to damage both the bit and the collet.

If you want to use twist bits like IRWIN left hand drill bits with an impact driver, put the bit in a hex-shank adapter or bit holder first. The adapter has a 1/4 inch hex shank on one end and a small chuck on the other. Then the steps are simple:

1. Take the battery out, or at least make sure the tool is off. You'd be surprised how many stuck-bit problems start with the trigger locked on.
2. Pull the collar on the nose of the impact driver toward the body to open the collet.
3. Push the hex shank of the bit or adapter in until it seats.
4. Release the collar so it locks back over the shank.
5. Tug on the bit. If it slides out or wobbles, it didn't seat fully. Pull it out and try again.

One more note from experience: an impact driver hammers rather than smoothly spins, so standard drill bits take a beating. For occasional short holes in soft material, an adapter is fine. For real drilling work, a drill/driver is the better tool.

When does it make more sense to skip IRWIN?

This may sound odd coming from someone who orders a lot of IRWIN, but I don't buy IRWIN for every job. A tool company that says this is not our specialty is more believable than one that claims to do everything.

If the job requires fully insulated tools rated for live electrical work, buy from a brand that specializes in that and holds the specific certifications. If a technician uses one tool all day, every day as their main income generator, a premium tool with a better warranty can be worth the extra money. The same goes for precision torque equipment and niche cutting tools.

That is not a knock on IRWIN. It's a procurement policy. I'd rather put IRWIN tools in the trucks for daily general work and spend premium money only where the premium actually pays back.

What's the smartest way to buy IRWIN tools without blowing your annual budget?

Stop buying replacements one emergency at a time. That's the process gap I see at most shops, including ours a few years ago.

We didn't have a formal restock process. The third time a tech asked for an urgent screwdriver order on a Friday afternoon, I finally created a simple tool request form and a par-level list. Now we keep spares of the items that fail or go missing most often: left hand drill bits, heavy duty screwdrivers, clamps, and common sockets. When someone pulls the last spare, it goes on the next purchase order. No rush shipping, no lost hours, no $60 delivery fee for a $12 hand tool.

The other habit that saved us money is tracking actual tool life. A $15 screwdriver set that lasts two weeks is a bad buy. A $45 set that lasts two years costs less per use. IRWIN is not always the cheapest line in the catalog, but for daily-use tools the cost per year tends to come out ahead. That's the bottom line.