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Diamond Mounted Points: 6 mm to 16 mm and What Each Grinds
A diamond mounted point is a small abrasive head bonded onto a steel shank, with a coating of diamond grit doing the cutting. It is the tool that gets hard jobs done when a file will not touch the material: hardened steel, carbide, glass, ceramic, stone and the tough coatings that blunt an ordinary burr in seconds.
The sizes in this range run from a 6 mm head up to a 16 mm head, supplied singly or in sets of three. Head size is the figure that decides both where the tool will reach and how much control you keep, and this guide explains how to choose between them.
What a diamond mounted point is good at
Diamond cuts by abrasion rather than by a sharp edge, so the tool works on almost any hard material and leaves a fine, controllable finish rather than the deep gouges a burr can produce. That makes it the right choice for refining a shape, opening a slot, dressing a weld or cleaning up a hardened surface where a file simply slides.
| Material | Diamond mounted point | Ordinary burr or file |
|---|---|---|
| Hardened tool steel | Cuts steadily | Slides or blunts immediately |
| Carbide and hardfacing | Cuts and refines | Barely marks the surface |
| Glass, ceramic and stone | Cuts with water or slow speed | Fractures the material |
| Aluminium and soft metals | Cuts, but loads the coating quickly | Better choice overall |
| Wood and plastic | Works, but quickly clogs | Faster and cheaper |
The exception worth remembering is soft, sticky metal. Aluminium and soft brass fill the gaps between the diamond grit and the tool stops cutting, which is why a burr is usually the better answer there. Diamond is for the hard, brittle and difficult materials, and for the fine work where a controlled scratch is more useful than a fast cut.
Head size: reach against control
A small head reaches into slots, holes and internal corners and gives fine control, because the contact area is small and the tool follows a line rather than biting. A large head removes more material across a wider face and stays flatter on a surface, but it will not enter narrow openings and it is easier to catch an edge with.
| Head size | Where it reaches | Removal rate | Suits |
|---|---|---|---|
| 6 mm | Slots, small holes, fine detail | Lowest, easiest to control | Deburring, blending a small weld, refining an edge |
| 8 mm | The general-purpose size | Moderate | Most workshop work on hardened steel |
| 10 mm | Open faces and shallow profiles | Good | Cleaning up a face and dressing a seam |
| 12 mm | Wider faces and internal radii | High | Larger areas where a flat face matters |
| 14 mm | Wide faces | Higher | Material removal before finishing |
| 16 mm | The widest faces in the range | Highest of the single sizes | Flattening and fast dressing |
The usual mistake is starting with the largest head. A 16 mm point on a small job will not fit where it is needed and will cut a hollow into a surface that was meant to stay flat. Starting at 8 mm and moving up only when the job demands a wider cut gives more control and uses the tool less brutally.
Diamond mounted points in this range
Every option in this range
Nine configurations: six single heads from 6 mm to 16 mm, plus three sets of three. Prices are per item or per set.
| Option | Suits | Price |
|---|---|---|
| 6 mm, single | Fine deburring and detail work | $8.99 |
| 8 mm, single | General workshop use | $10.01 |
| 10 mm, single | Open faces and shallow profiles | $10.75 |
| 12 mm, single | Wider faces and radii | $11.49 |
| 14 mm, single | Material removal before finishing | $13.53 |
| 16 mm, single | Fast flattening and dressing | $14.64 |
| 6, 8 and 10 mm, set of three | A working set for general use | $26.97 |
| 12, 14 and 16 mm, set of three | A working set for larger surfaces | $26.97 |
| Six-piece set | The full size ladder in one box | $26.97 |
The arithmetic is worth doing before buying singles. Three separate points bought one at a time cost more than the equivalent set, and a six-piece set at the same price as a three-piece one is the best value in the range if the sizes will actually be used. Where only one size is ever needed, a single point is the sensible purchase.
Making a diamond point last
- Keep the speed down; a diamond point cuts better slowly than it does at full speed.
- Use water or a light oil as a coolant on glass, ceramic and stone to stop the coating loading.
- Let the tool do the work and avoid pressing hard, which strips grit from the bond.
- Reverse the direction of travel so the grit wears evenly across the head.
- Clean the head after use; dried swarf between the grit particles is what stops it cutting.
- Store the points separately so the heads cannot rub against each other in the box.
When a diamond point stops cutting
A diamond point wears in a predictable way. It first cuts slower as the grit flattens, then it starts to slide rather than abrade, and finally the bond between grit and head fails and the coating strips away in patches. The middle stage is recoverable: cleaning the head and running it briefly on a soft dressing block exposes fresh grit and restores the cut.
The final stage is not recoverable. Once the coating has stripped, the tool is a smooth steel shape and will burnish a surface rather than remove it, which can look as though the tool has stopped working for no reason. Checking the head under a light before a job saves the confusion of fighting a worn tool to the end of an afternoon.
Frequently Asked Questions
What is a diamond mounted point used for?
Grinding and refining hard materials: hardened steel, carbide, glass, ceramic and stone, plus deburring and blending where a file will not cut.
Which head size should I start with?
8 mm covers the widest range of work. Add a 6 mm point for fine detail and a 12 mm or larger head only when a job needs a wide, flat cut.
Can I use a diamond point on aluminium?
You can, but the soft metal loads the coating and the tool stops cutting. A burr is a better choice for soft metals.
Should diamond points be used wet or dry?
Dry on steel is normal. On glass, ceramic or stone, a little water keeps the head cool and stops the coating clogging.
Why has my point stopped cutting?
Usually the coating is loaded with swarf or the grit has flattened. Clean it and dress it briefly on a soft block; if the coating has stripped, the point is finished.
Choosing the right point
Start with the smallest head that will do the job and work up. The diamond mounted point range covers 6 mm through 16 mm as singles and as sets of three and six.
