So how often have you seen online videos with ‘Tutors’ using diamond plates to sharpen their plane irons, chisels, etc? They work well, right? But for how long, even with the ‘Recommended lapping Fluid” promoted as a requirement?
When I started the Tooltique business I, like many others, got sucked in by these ‘new Improved’ diamond sharpening plate products and bought a selection ranging from £10 – £100 to see the difference, after all, we sharpen the very same vintage hand tools we sell. Result: The most expensive didn’t last a fortnight and was as smooth as a baby’s bottom by week three.
I’m not going to slate specific makers in this article because, in my opinion from experience, not one diamond sharpening plate I bought proved to be of good value. Likewise, the carbon footprint must be astronomical when creating artificial diamonds that rely on very cheap electricity which wouldn’t meet any Net Zero policy.
These aren’t an improvement on traditional methods that work extremely well as long if the Right Lubrication is Applied. Once you have an oil stone, experiment and test what oils work best.
Course oil stones require motor oil even to the extent of grease or a combination of the two because of the penetration aspect of the large grits. I.E. 100-300 Grit
Medium oil stones such as Carborundum require motor oil, a 3in1 oil, or a combination of the two depending on the Grit size. I.E 300 – 600 Grit.
Fine man-made oil stones such As a Norton India can last many years and are probably the most important stone for creating a much finer burr. These are usually approximately 1000-1200 Grit. Acutus Lapping Oil is a cost-effective option that works well with these low-cost stones.
Very Fine Natural oil stones such As Welsh Slate, Washita, Llyn Adwal, and Charnley Forest as examples require a very thin lapping oil that doesn’t cause the tool edge to skate and helps stop the pores from clogging by having an agent cleaner. The Grts Can Vary between 5000 Grit up to 15000 Grit. Again Acutus Lapping Oil is a cost-effective option.
Water Stones Are Better for Kitchen Knives etc because of hygiene.
If a flat surface is needed and this is the reason to tempt you into buying a diamond sharpening plate, firstly they aren’t that flat compared to a piece of 10mm thick float glass and a sheet of scary sharp!
In our workshop, we establish a primary edge with a grinder but this final stage of the sharpening process that assists in a sharper longer longer-lasting edge requires hand work. We use a Norton India or similar approx 1000 grit, then a piece of Welsh Slate which is approx 7000 grit before stropping off using a polishing compound on the leather glued to a wooden backing.
It’s Cheap, effective, and very long-lasting, I’ve been using the same two stones for over 10 years and they are still going strong. It makes me wonder why diamond sharpening plates were ever produced other than to lead people down a costly replacement cycle.
