If you've ever managed tooling spend, you know how a harmless "we'll just use reamers" decision can end with a drawer full of single-purpose cutting tools. I've been the procurement manager at a mid-size contract machining shop for six years, managing a tooling budget of roughly $80,000 a year. And I've watched the reamer habit quietly eat a bigger share of that budget than any of us realized.

This article compares two ways to finish precision holes: the classic reamer drill bit approach versus Tungaloy boring bars, which we run with their BXA20 tool holder. I'll judge them on three dimensions that matter to a shop's bottom line: setup flexibility, precision consistency, and total cost of ownership (TCO). I'll also address the new-tech question—whether a 15W CO2 laser machine or the fastest industrial 3D printer changes any of this.

Let me get one thing straight: I'm not here to bury reamers. There are legitimate places where reamers are the right call. But if you're a job shop like ours—different parts, different diameters, weekly drawing changes—the math cuts differently.

What Is a Reamer Drill Bit Used For?

Quick primer, in case you're new to this: a reamer drill bit is a finishing tool. It doesn't start a hole. It follows a pre-drilled or pre-bored hole and removes a relatively small amount of material—usually 0.1 to 0.5mm of stock, depending on the diameter—to bring the hole to a precise size and surface finish. Standard reamers hold tolerances around H7. For a 20mm hole, that's roughly +0.02/-0.00mm. If you're making one part in high volume with one hole diameter, the reamer is probably the most cost-effective tool you will ever buy. It repeats. It's fast. It's boring, in the best possible sense.

But here's the catch that nobody mentions when you buy your first one: a reamer is dedicated to exactly one diameter. A 12mm reamer finishes 12mm holes. It will never, in its working life, make an 11.8mm hole or a 12.5mm hole. You stamp "12MM" on the tool, and that's its purpose until it wears out.

The Flexibility Question: Dial It In or Buy More Tools?

In a job shop, flexibility is what lets you quote a Tuesday morning RFQ and start cutting Thursday. The Tungaloy boring bar system handles this really well. The bar adjusts to the diameter you need, and the BXA20 tool holder provides the rigidity for the kind of interrupted cuts that come with varying stock conditions. You set the diameter, mount the insert, measure, adjust—done. That's it. If the next job needs a different size, you adjust again, and you're running.

Reamers don't do that. If a drawing calls for 11.8mm and you only own a 12mm reamer, you have two choices: buy a new reamer or turn down the job. Over time, what happens is you accumulate one reamer for every diameter you've ever cut. A drawer full of single-purpose tools, each one purchased with good intentions, 85% of them gathering dust at any given time.

I assumed this "collection" was normal. Didn't question it for the first two years. Then my inventory audit showed we had over $2,100 in reamers sitting on the shelf—several never used once since the day they arrived.

The verdict on flexibility: the boring system wins, clearly.

Can a Boring Bar Really Match Reamer Precision?

The fair point for the reamer camp: once a reamer is sized correctly and running in a rigid setup, it repeats. The tool governs its own hole size. The operator's main job is keeping the reamer concentric with the pre-hole. That's why high-volume production lines love them. The consistency is literally built into the tool.

Boring asks a bit more from your people. You're measuring, adjusting, cutting, measuring again. It's interactive. There's an old machinist's saying that "reamers are accurate and boring bars are fiddly." There's a grain of truth in it—but only a grain. Modern inserted boring bars, set up correctly in a rigid holder, hold H7 tolerance routinely. (Should mention: our operators came around once they got used to the Tungaloy system. The insert seating is predictable, and the BXA20 holder feels much more rigid than the cheap collet setup we ran before.)

Here's the thing: reamers deliver easy consistency with lower operator skill. Boring matches the result with a skilled operator and gives you in-process control. If your shop has high turnover and you need reliable holes from less-experienced people, that's a real point for reamers. I won't pretend otherwise.

The verdict on precision: reamers win on ease, boring wins on control.

The TCO Number That Changed Our Tooling Strategy

This is where the spreadsheet changes your mind. What I mean by total cost of ownership: purchase price, replacement frequency, inventory carrying cost, and the cost of tooling lead times when a job needs a size you don't have.

Over roughly the last four years of tracked orders, here's what the numbers look like. I should preface this by saying I'd have to open the full inventory logs to give you exact figures—I'm working from memory and the summary reports, so don't quote me on every penny.

The reamer route:

  • We carried reamers for six common sizes: 10, 12, 16, 20, 25, and 32mm.
  • Average price for a quality reamer in that range: $85 to $110 each.
  • Initial purchase: about $510.
  • Replacement reamers over four years—twelve total: roughly $1,020.
  • Three "emergency" custom reamers for odd-diameter jobs, around $150 each: $450.

Total reamer spend: approximately $1,980.

The boring system route:

  • Tungaloy boring bar plus BXA20 tool holder: around $700 upfront, from a single purchase order in 2023.
  • Inserts: $25 to $35 each, and each insert has multiple cutting corners. We used roughly two dozen inserts over four years: $600 to $720.

Total boring system spend: approximately $1,300.

That's about $680 in savings over four years—roughly 34%. And here's the part that surprised me: the boring system covered every diameter the reamer set covered, plus the odd sizes that cost us $450 in custom reamers, plus sizes we haven't run yet. One system did the work of a fleet.

The hidden cost that never shows up in the ledger: custom reamers have lead times. A $150 "emergency" reamer that arrives in three weeks can cost you the job. The boring system can adapt to an unexpected diameter the same afternoon you get the RFQ. That kind of responsiveness doesn't appear in the purchase ledger, but it shows up in revenue—and in which customers keep coming back.

I'll be fair, though: in a high-volume shop making the same hole every day, reamers beat boring on cycle time and operator skill requirements. TCO isn't a universal scoreboard. It's a framework, and the framework is the point.

What About 15W CO2 Laser Machines and Industrial 3D Printers?

Around the time we were doing this analysis, one of our engineers proposed that we buy a 15W CO2 laser machine to "modernize our fabrication." I get the instinct. These machines are genuinely useful for engraving, marking part numbers, cutting acrylic and plywood for fixtures, and light work on non-metallic materials. We did end up getting one, and it's been great for exactly those tasks.

But it doesn't replace a boring system. A 15W CO2 laser machine will not cut a precision hole in stainless steel. It'll mark the surface at best if the material is coated or anodized. Cutting structural metal with a laser requires kilowatts, not 15 watts. It's a different universe.

As for the fastest industrial 3D printer—it's impressive for prototyping. We use ours for fixture design verification, concept models, and the occasional tool we'd otherwise have to buy. But the material properties, surface finish, and tolerance class for production metal parts—especially anything with an H7 hole—aren't there yet. Whatever you print still needs machining. If you're printing a part and then finishing it with a boring bar, you've subtracted time on the roughing, not replaced the precision tooling.

These are complements, not substitutes. The laser and the printer earn their keep alongside the boring bars, not instead of them.

So: Reamer or Boring Bar?

Scenario by scenario:

  • High-volume production, one part, one hole size, running for months: reamer drill bit, without a doubt. Optimize it and never look back.
  • Job shop or contract machining with mixed diameters: Tungaloy boring system. The flexibility advantage plus the TCO savings are too large to ignore.
  • Blind holes with tight callouts: boring. In-process control saves your sanity when a blind hole doesn't come out right the first pass.
  • Prototypes and one-offs: print the concept, machine the final. Use the laser to mark and engrave—it'll pay for itself in a year.

The bigger lesson, though, goes beyond reamers versus boring bars. It's about treating every purchase as a system decision. A reamer isn't just a $90 tool: it's a commitment to that one diameter, forever. A boring bar and a quality tool holder is a commitment to an approach that can handle whatever comes through the door. There's something satisfying about a tooling decision that survives management review and still makes sense a year later. After our first full fiscal year with the boring system, our tooling line item came in well under budget. My boss asked if I'd negotiated a discount. I told her no—I'd just made better purchasing decisions.

That said, I can only speak to our context. We're a mid-size job shop with varied work and experienced operators. If you're running a single-customer production line with year-long planning visibility, the calculus is different. Reamers might win for you entirely.

My real recommendation is the framework itself: track the total cost, not the sticker price. The numbers don't lie.