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The DMT Dia-Sharp® Magna-Disc Sharpening and Honing Systems are surprising in how quickly they put a very sharp edge on your tools. They also appear to resist wear very well.
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DMT Dia-Sharp® Magna-Disc Systems

Diamonds in the rough make steel smooth and sharp

Text, photos and video by Tom Hintz

Posted – 3-5-2011

The folks at DMT (Diamond Machine Technology) have been producing sharpening products with diamonds for years and have built a good name for themselves in that field. I should add that DMT produces their products in the USA so that is another major point in their favor. However, for the purposes of this review we are interested in how well the DMT Dia-Sharp® Magna-Disc Systems work on the Work Sharp® 3000 Sharpener for which they were designed. Once again American ingenuity wins.

The Basics

The DMT Dia-Sharp® Magna-Disc Systems come in sharpening and honing versions. Both come with a magnetic backer disk that actually holds the abrasive disks in place on the Work Sharp® 3000 Sharpener. The magnetic disk has a pressure sensitive adhesive on the back so it can be applied to one of the standard glass wheels supplied with the Work Sharp® 3000 Sharpener. This magnetic disk is what makes changing grits in both systems so quick and easy.

All of the diamond encrusted disks as well as the fabric-covered disk in the honing system are metal so they stick to the magnetic disk without assistance. I was initially concerned about the strength of that magnetic bond but was proved wrong when I started using these systems. You are going to have to do something exceedingly heavy-handed to move one of the abrasive disks while sharpening or honing.

Both sets come with the magnetic backer disk (left) that actually holds the grit disks in place. The grit disks (right) are made from thin metal, work exceptionally well and stay put until you want to change them out.
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The diamond grinding disks do become somewhat discolored with debris after cutting but the majority of that can be brushed away. The crepe abrasive cleaner also works well on the diamond disks.

Sharpening System

The DMT Dia-Sharp® Magna-Disc Sharpening System comes with two metal abrasive disks and the magnetic base disk. You get one 325-grit and one 600-grit disk. I know these grits sound more like honing territory and probably are with mere ceramic or mineral abrasives. However with diamond chips the cutting is much more effective and material removal is surprisingly quick. When it comes to diamond dust, less does more so to speak.

Because the diamond abrasives are bonded to a metal disk rather than paper the whole disk functions somewhat like a heat sink and tends to draw heat away from the tool being sharpened. That lets you sharpen longer without fear of compromising the tempering in the tool. I discovered that the ease with which the DMT Dia-Sharp® Magna-Discs cut means that little pressure is needed to remove material. Just hold the tool against the abrasive wheel and let the diamonds do their work. That same easy cutting action also means that the Work Sharp® 3000 Sharpener isn’t laboring which should translate into a longer life for it as well.

Honing System

The DMT Dia-Sharp® Magna-Disc Honing System comes with an identical magnetic backer disk to the one in the Sharpening kit, a 1200-grit metal disk and a special fabric-covered metal disk along with an application syringe of a special 3-micron honing paste.

Applying the included 3-micron paste (left) preps the fabric honing disk. Hole the bevel against the honing disk (right) and it is surprising how quickly it starts to shine.
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The 1200-grit disk does a remarkable job of smoothing the bevel and cutting edge. In fact I was more than a little surprised at how quickly it works. I didn’t spend a lot of time grinding the chisel used for this review but it got very sharp very quick. During the evaluations I was a little under the gun on time but the DMT Dia-Sharp® Magna-Disc Honing System was shining up the bevel very quickly. Even the 3-micron abrasive compound works surprisingly fast and requires very little be applied to the fabric disk, especially after it is loaded the first time.

In the Shop

Using the DMT Dia-Sharp® Magna-Disc Systems was a definite eye opener. I admit to being skeptical of the capabilities of these diamond grits initially as I removed them from the packaging. I expected the bevel to get shinny eventually but to find very little material being removed. I discovered how wrong I was from the first time I put chisel to a DMT Dia-Sharp® Magna-Disc System disk. After just a few seconds as seen in the video, the entire bevel was clean and smooth.

The idea of using a magnetic backer really is a time saver. Not having to remove an adhesive-backed piece of paper is way easier. Not having to clean away what adhesive remained on the glass disk between grits is an even bigger time saver. Combine those setup time savings along with the fast cutting performance of the DMT Dia-Sharp® Magna-Disc Systems and sharpening jobs tend to get done quicker and better than with many other types of sharpening machines and abrasive systems.

I expect that with the price of the DMT Dia-Sharp® Magna-Disc Systems lifespan will be a concern for potential buyers. I paid close attention to what the grit disks looked like before starting this test and how they looked after. I didn’t do extensive grinding but after the testing Work Sharp® 3000 Sharpener complete the disks appear to be untouched save for a bit of debris that mostly brushed away. I think the key is to use light pressure and let the diamond grit do its job. With a little common sense I do not see wear as being a big issue with either of the DMT Dia-Sharp® Magna-Disc System kits.

Video Tour


One of the DMT claims is that their diamond grit disks that are supplied in the DMT Dia-Sharp® Magna-Disc Systems will outlast paper abrasives by a margin of 50 to 1. I don’t have the time to actually try and burn one of the diamond disks down, especially since I have yet to see any wear at all. What is easy to see is that the performance of the DMT Dia-Sharp® Magna-Disc Systems does not degrade at a noticeable rate. The diamond grit is fast cutting and with such fine grades, the surface they leave is exceptionally smooth. Sharpening a chisel or plane iron with the DMT Dia-Sharp® Magna-Disc Systems is a quick process that creates an extremely sharp edge.

With a street price of just $94.99 for the Sharpening kit and $74.95 (3-5-2011) for the Honing set, the DMT Dia-Sharp® Magna-Disc Systems do have an initial cost. However, it is not difficult to see how these systems could save money down the road. Being able to produce such a sharp edge so quickly will also make your shop run a little more smoothly and that translates into more quality time for your projects. None of us seem to have enough time anymore but the DMT Dia-Sharp® Magna-Disc Systems help you make better use of what shop time you are able to carve out.

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