6 Best Metal Hole Saws For Custom Shim Cutting Reliable Options

Custom shims are frequently required when leveling out uneven decking or creating pitch adjustments for roof-mounted equipment. Precision in cutting these materials from metal stock requires a hole saw capable of handling tough alloys without wandering or overheating. Selecting the wrong bit often leads to jagged edges that compromise the structural integrity of the shim’s fit. Proper tool selection ensures consistent results across every penetration point on the job site.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Milwaukee Hole Dozer: The All-Around Workhorse

The Milwaukee Hole Dozer stands as the standard for general site use due to its reinforced tooth geometry. It features a Rip Guard edge that effectively resists tooth stripping when hitting unexpected hardened spots in scrap metal or fastener remnants.

For contractors moving between light-gauge flashing and thicker steel plates, this saw provides reliable versatility. It maintains a consistent cutting speed without requiring constant pressure, which preserves the life of the drill motor.

When the goal is to punch out shims in bulk, the Hole Dozer delivers predictable, repeatable performance. It remains the most sensible choice for the toolbox where one tool must handle a wide variety of materials.

Diablo Carbide Hole Saw: Fastest Cleanest Cuts

Diablo’s carbide-tipped hole saws represent a significant leap in efficiency for high-volume fabrication. These bits cut through heavy-gauge metal significantly faster than standard bi-metal versions.

The primary advantage lies in the clean, burr-free edge left behind, which is critical when a shim must sit perfectly flush against a metal roof purlin or deck. A cleaner cut means less time spent with a file or grinder smoothing down edges before installation.

These saws are best reserved for clean, precise work where speed is an asset. Avoid using these on materials containing hidden nails or screws, as the carbide teeth are susceptible to brittle failure upon high-impact contact.

Lenox Speed Slot: Easiest Plug Removal on Site

Plug removal is often the most time-consuming part of repetitive shim cutting. The Lenox Speed Slot system utilizes a tiered hole design that allows for easy leverage, making it possible to eject a metal slug in seconds.

This design feature prevents the frustration of prying stuck metal pieces out with a screwdriver, which often dulls the edge of the bit. The saw also benefits from a thicker backing plate that resists flexing during heavy-duty drilling.

For roofing jobs involving repetitive metal shim fabrication, time saved on plug removal adds up quickly. It keeps the work pace steady and reduces the physical strain on the operator during long production runs.

DeWalt Impact Ready Hole Saw: Built for Impacts

DeWalt Impact Ready saws are engineered for the realities of modern cordless drills and impact drivers. These bits are optimized to handle the high-torque, stop-start nature of driving fasteners into metal framing.

While primarily designed for anchors and fasteners, they perform exceptionally well when cutting custom shims from medium-gauge steel. The durability of the shank prevents the bit from snapping or bending when the drill stalls unexpectedly.

Use these when the project requires moving from drilling holes for structural bolts to cutting shims without swapping out the tool setup. They provide the necessary ruggedness for the most demanding site conditions.

Starrett Carbide Tipped: The Precision Choice

Starrett is the name synonymous with tight-tolerance machining. When a shim requires an exact diameter to fit around a specific pipe flashing or conduit, this is the tool that delivers dead-on accuracy.

These saws minimize chatter and vibration, which is essential when drilling into thin sheet metal that might otherwise buckle. The carbide tips hold an edge far longer than standard steel, maintaining consistent sizing over hundreds of cuts.

If the job scope involves high-precision mounting on expensive finished metal systems, the Starrett is the professional’s preference. It justifies the higher cost through the elimination of wasted materials and scrapped shims.

Klein Tools Bi-Metal Saw: Pro-Grade Durability

Klein Tools focuses on the endurance required by mechanical and structural contractors. Their bi-metal hole saws are built with a robust composition that stands up to the constant heat generated when cutting through stainless or galvanized steel.

The depth of these saws is perfectly suited for standard metal stock thicknesses. They provide a predictable cut that doesn’t wander, even when the pilot drill bit begins to show signs of wear.

When reliability is the priority over sheer speed, Klein is a top-tier contender. They represent a solid, middle-ground investment that survives the rough-and-tumble environment of a job site truck.

Bi-Metal vs. Carbide-Tipped: Which Do You Need?

The choice between bi-metal and carbide-tipped boils down to the material being cut and the frequency of use. Bi-metal saws are flexible and shock-resistant, making them ideal for cutting materials that might contain hidden hazards.

Carbide-tipped saws excel in speed and longevity but lack the toughness to survive accidental impacts. Use bi-metal for rough construction and site-demolition scenarios, and reserve carbide for controlled fabrication tasks.

Always assess the thickness of the shim stock before choosing. Carbide saws can sometimes “grab” thin, lightweight metals, causing them to deform, whereas bi-metal saws offer a more forgiving cutting action for thinner gauges.

Cutting Speeds and Lubrication: The Pro’s Secret

Running a hole saw at high speed is the fastest way to ruin a perfectly good bit. For metal, slow and steady is the rule, as heat is the primary enemy of both the metal being cut and the teeth of the saw.

Always apply a quality cutting oil or coolant to the surface before starting. Lubrication reduces friction, prevents metal chips from welding to the teeth, and allows the bit to pull cleanly through the material.

If the metal starts to change color or smoke, stop immediately. Adding a few drops of oil will not only extend the bit’s life but also result in a much cleaner, more accurate shim that requires zero secondary filing.

Choosing the Right Arbor for Your Hole Saw Setup

The arbor is the bridge between the drill and the saw, and a loose or weak arbor is a liability. For custom shim cutting, opt for a quick-change arbor that locks the saw securely to prevent rotation slippage.

Ensure the pilot bit is sharp and matches the arbor’s requirement for the hole size. A loose pilot bit will allow the saw to “walk,” turning a precise circular shim into an oblong piece of unusable metal.

Always carry a spare arbor or an adapter kit in the tool bag. A stripped thread or a broken arbor pin should never be the reason a roofing project grinds to a halt mid-afternoon.

Safety Tips: Avoiding Kickback and Damaged Bits

Never use a hole saw without a drill equipped with a side handle. If the bit binds, the torque transferred to the wrist can lead to serious injury or dropped equipment from a ladder or roof surface.

Secure the metal stock firmly in a vise or use heavy-duty clamps when cutting. Holding the material with a hand or foot is a recipe for lacerations and uneven, unsafe shim edges.

Wear impact-rated eye protection consistently, as metal shavings from hole saws act like shrapnel when the bit breaks through the material. A well-secured piece of stock and a steady hand are the final requirements for professional-grade metal fabrication.

Proper tool maintenance and selection elevate the quality of any installation, ensuring that every shim serves its purpose without failing under load. By matching the saw to the material and sticking to disciplined cutting practices, even the most challenging roof adjustments become manageable. Keep these options on hand, and you will find that precision fabrication is a repeatable skill rather than a source of site frustration.