Diamond files are indispensable tools for jewellers, watchmakers, glass artists, and DIY enthusiasts. Whether you’re refining clock parts, shaping gemstones, bevelling glass, or sharpening carbide tools, these abrasives deliver precision, longevity, and a flawless finish. In this complete guide, you’ll learn what diamond files are, how they compare with traditional steel files, tips for choosing the right grit, and twelve practical ways to use them.
What is a Diamond File?
Diamond files are made by electroplating industrial-grade diamond grit onto hardened steel blanks with a nickel bond. The smaller the diamond particles, the finer the grit – similar to sandpaper. Higher grit numbers mean a smoother finish: for example, a 600 grit file is much finer than a 220 grit file.
Why Use a Diamond File Instead of a Traditional Steel File?
Diamond File vs Traditional Steel File Comparison
| Feature | Diamond File | Traditional Steel File |
|---|---|---|
| Abrasive Material | Electroplated diamond grit | Steel teeth |
| Cuts in All Directions | Yes | No |
| Works on Hard Materials | Yes (e.g. carbide, glass, stone) | Limited |
| Typical Grit Range | 120 – 900 grit | Coarse to super fine |
| Longevity | High (especially with wet use) | Shorter lifespan on hard materials |
Unlike toothed steel files that only cut on the forward stroke, diamond files have no “teeth.” Their abrasive grit cuts in any direction making them ideal for fine, controlled work on very hard materials.
How to Use Diamond Files: 12 Practical Applications
Here are twelve of the most popular ways professionals and hobbyists use diamond files. For most tasks, 600 grit is a good all-rounder, while 900 grit is perfect for superfine finishing.
1. Detailing Ring Shanks & Intricate Jewellery
Use the fine points of a round diamond needle file or large 600 grit file to smooth inside ring bands or remove deep burrs. Rotate the file inside holes or around shanks for 360° cutting.
2. Sharpening Carbide Cutting Tools
Tungsten carbide gravers and burrs stay sharp longer with quick touch-ups using a 600 grit diamond file.
3. Enlarging Holes
A round diamond needle file makes easy work of opening up screw holes, beads, and clock jewels. Use 600–900 grit for smooth results. Other useful tools for expanding holes are diamond twist drills and cutting broaches.
4. Removing Excess Solder
Clean up solder joints on earrings or ring bands with a square 900 grit file. A round file is excellent for inside bands.
5. Fitting Watch & Clock Glasses
When adjusting watch or clock crystals, a 600 grit diamond needle file produces a precise fit quickly.
6. Refacing Clock & Watch Pallets
For burred or misshapen pallets, a 900 grit diamond file restores smooth surfaces and improves movement.
7. Shaping Precious Stones
Quartz, sapphire, and ruby can be carefully shaped with 600 or 900 grit diamond needle files. Try a flat 600 grit file or a half-round 900 grit for cabochons and settings.
8. Repivoting Clocks & Watches
Remove burrs and wear on pivots with a 600 grit diamond needle file for smooth, accurate running.
9. Bevelling Cut Crystal & Glass
Repair chipped crystal rims or smooth cut bottle edges with a half-round 600 grit file. It’s also ideal for tidying mosaic tiles.
10. Sharpening Household Tools
Keep scissors, knives, screwdrivers, and even guitar and violin strings sharp using a 600 grit diamond file.
11. Refreshing Burnishers
Only diamond files can restore the cross-grain on sapphire burnishers or hardened steel tools. A 600 grit file is perfect.
12. Sharpening Fishing Hooks & Ice Screws
One of the most important tools of an angler has to be his hook, and in carp fishing in particular, this has to be razor sharp (sticky sharp). For sticky-sharp fishing hooks or winter-climbing screws, use a flat 600 grit diamond file or a fine escapement file for intricate points.
Diamond Files cut in all directions produce a better finish
The distribution of diamond particles enables the diamond needle file to not only cut in all directions but also produce a much better finish. Therefore, diamond needle files can offer a fantastic abrasive for a variety of applications.
Due to the hardness of diamonds, diamond files can be used on a variety of materials that other abrasives will not have an impact upon.
Diamond Files cut on the pull stroke as well as the push stroke
When you're working in small, intricate areas, the diamond file will work on the pull stroke just as effectively as it does on the push stroke. So this may make it slightly easier in confined spaces. It also means, in theory, that it will cut twice as fast as a toothed file of the same grit because it cuts on both the pull and push strokes.
Another huge advantage is the fact that they also work sideways and with a twisting motion.
How to Clean & Care for Diamond Files
Always use your diamond files wet where possible — water or a light oil helps keep debris from clogging the grit. After use, rinse and dry thoroughly. If material becomes stuck, try one of these methods:
Scrub the file gently with mild soap and a soft toothbrush. For stubborn particles, run a brass bristle wheel or steel bristle wheel in a rotary tool over the surface. Alternatively, rub the file across a white aluminium oxide stick or a piece of soapstone to loosen residue.
Store files completely dry to protect the steel blank from rust.
Recommended Diamond Files
We stock a wide range of diamond files for jewellery making, watch and clock repair, glasswork, and hobby projects.
Jewellery & Stone Work: For shaping cabochons or tidying settings, try the Flat 600 grit diamond file or the Half-round 900 grit file for superfine finishes.
Watch & Clock Repair: When you need control and precision, our 900 grit square needle file and Large round 600 grit file are ideal choices.
Glass & DIY Projects: For bevelling glass edges or smoothing mosaic pieces, a half-round medium diamond file makes the job easy.
Fast material removal: For removing material quickly, a coarser diamond file works wonders, a large flat 150-grit diamond file will work with speed.
Browse our full collection of diamond files here and find the perfect tool for your next project.
