StewMac Gauged Nut Slotting File.020 in Width - Precise Nut Work

In this review the StewMac Gauged Nut Slotting File.020 in width is assessed for luthiers and hobbyists who need precise, repeatable nut and saddle slots. The bottom line: it is a straightforward, professional tool that produces clean, round-bottom slots so strings seat properly without buzzing. The tempered edge-cut design and twin 4in cutting edges make the file feel efficient and reliable for small repairs or shop work where accuracy matters more than bulk value.

Key Features

• Tempered edge-cut blade: Provides a long-lasting cutting edge that keeps its profile through repeated use for consistent slot shape.
• .020 in gauged width: Matches thin string gauges or lets you control slot width when rocking the file slightly to widen a groove.
• Twin 4in cutting edges: Two usable edges extend tool life and let the user flip the file for continued sharpness during a session.
• Chrome-alloy steel construction: Feels sturdy and resists wear when used on bone, synthetic nuts, and metal saddles.
• Round-bottom slot profile: Produces a seated string pocket that reduces buzzing and improves string contact at the nut or saddle.

Who It's For

This file is aimed at busy repair shops and hobbyist luthiers who need a compact, accurate hand tool for nut and saddle work. It suits anyone who prefers to size files to string gauges and who wants a reliable, repeatable round-bottom slot without specialized machinery.

Players who only change strings occasionally or expect a multi-tool for general maintenance may find the single-width, purpose-built file less versatile; those users should consider broader kits with multiple sizes. Likewise, if value per dollar is the primary concern, some buyers consider single files a premium purchase.

Pros & Cons

Pros

• High-quality cutting action produces accurate, round-bottom slots for clean string seating.
• Tempered chrome-alloy steel holds an edge and feels durable under shop use.
• Twin 4in edges extend usable life by allowing the file to be flipped.

Cons

• Some users may find a single-size file thin or small for heavy use and consider it a higher-priced specialty tool.

Specifications

Our Verdict

The StewMac.020 in nut slotting file is a focused, professional hand tool for those who need precise nut and saddle slots; it excels at producing a clean seat and holds up for repeated use. It represents good value to luthiers and shops that prioritize accuracy and a long-lasting cutting edge, though casual users may prefer multi-size kits for broader coverage.

Frequently Asked Questions

Can this file be used for metal saddles?
Yes; the chrome-alloy steel file is suitable for Tune-o-matic style metal saddles when the correct size is chosen.

How should I choose the file size?
Pick a file the same size as the string gauge or a few thousands larger; a slightly smaller file can be rocked side-to-side to widen the slot.

How long do the cutting edges last?
Edge life depends on use, but the tempered steel and twin edges extend life and let you flip the file to use fresh cutting surfaces.