Sharpening

Diamond Types - Diamond sharpening tools are manufactured of two types of industrial diamonds – monocrystalline and polycrystalline.

• Monocrystalline Diamonds: These diamond products are well suited for sharpening the tools we discuss below because they wear well and maintain a consistent grit size. This is critical in sharpening hard steels requiring a range (or sequence of grits) to achieve the final edge.
• Polycrystalline Diamonds: Some products offered by diamond tool manufacturers utilize polycrystalline diamonds which fracture much as natural media used in sandpaper like aluminum oxide. This results in a constantly changing grit size. While this type of diamond is highly effective in industrial finishing applications, it is perhaps not the best choice for an expensive diamond plate due to a rapidly diminishing grit size.

Diamond Plate Types - DMT manufactures two types of monocrystalline sharpening plates - continuous and interrupted. Both types of products work well in a variety of applications. There are circumstances in which one has advantages over the other.

• Continuous products: such as the DiaSharp series have the entire surface evenly coated with diamonds. Continuous surface products work best when kept wet to carry away the swarf. The lack of holes prevents tips on pointed objects such as carving tools from falling into the hole and they leave a consistent scratch pattern. We recommend these products as part of a sharpening system for Chef’s Knives, Carving Tools, Plane Irons & Chisels, Straight Razors and touching up carbide tooling.
• Interrupted surface products: utilize a plastic substrate and holes in the cutting\surface which serve to collect swarf from the sharpening process. In our experience, interrupted surface products work better for chef’s knives, pocket knives and similar straight bladed tools where speed is important and water for lubrication may not be available, or convenient. We found these products to wear more quickly under heavy use and sometimes leave noticeable marks in the sharpened-surface due to the holes in the surface of the plate.

Flattening Waterstones: Customers often ask if it is appropriate to use DMT DiaSharp 8” diamond plates to flatten waterstones. On the surface this seems like a good idea, but in practical application, only the DMT Dia-Sharp D8XX 8×3x3/8 in. Diamond Plate is suitable for some waterstones. This is because the diamonds are large enough to create an “air break” between the surfaces of the waterstone and diamond plate so the two don’t stick together due to the surface attraction of the water. It should also be noted that waterstones will quickly remove the nickel holding the diamonds in place on finer DMT plates.

• We recommend the DMT D8XX for use on Norton and King Brands of waterstones. The plate will quickly remove an appropriate amount of material.
• We do not recommend use of this diamond plate on ceramic media waterstones such as those made by Shapton. Shapton waterstones wear very slowly due to their sharp and durable ceramic media requiring a very small amount material to be removed. Use of this plate on a Shapton product will cut away the media much too quickly and leave too rough a surface on the waterstone.

DMT, the manufacturer of the diamond plates we offer is located in Marlborough, MA.

Originally posted Wednesday, October 29th, 2008

How does Shapton GlassStone media differ from traditional man-made waterstones?

Shapton uses a finely graded ceramic media which is very hard and sharp. This results in waterstones which wear slowly and do not need pre-soaking. Another characteristic of the GlassStone series is the ability of the stone to both cut and polish at the same time. While this may sound counterintuitive, some of the ceramic particles are worn smooth while others more recently revealed are sharp. This nets out to a more polished finish with less work as you progress to finer grits.

Is there an advantage to the ceramic-on-glass construction of Shapton’s GlassStones?

As traditional waterstones wear and become thin, they also become weak and frequently crack ending their useful life. GlassStones allow full use of the media because it can be worn all the way down to the glass.

The ceramic media on the GlassStones seems pretty thin. How long will it last?

We’re frequently asked this question and it’s a little difficult to quantify. We’ve used using Shapton GlassStones in our showroom daily for an extended period of time. With proper care, we conservatively expect them to last twice as long as an equivalent set of one-inch-thick single grit traditional waterstones.

Do I need to concerned about flattening Shapton waterstones?

It depends to some degree on what you are sharpening. Plane Blades, Chisels and Straight Razors have straight blades which are very sensitive to irregularities in the surface of the waterstone. We recommend frequent flattening when sharpening these types of blades. Cutlery tends to be more forgiving (except for knives with perfectly straight blades) so flattening can be done less frequently. In our showroom we flatten after each sharpening. This way we know the stones are flat when we start to use them. Since we’re only taking off a couple thousandths of an inch with the Glass Diamond Lapping Plate, waterstone wear really isn’t a concern.

Is there a flattening option besides the Shapton Glass Diamond Lapping Plate?

We believe the Shapton Glass Diamond Lapping Plate is the best choice because of it’s precision flatness (+/- 5 microns), but the GlassStones can also be flattened using 220-320 Grit wet & dry sandpaper mounted on a flat surface such as a granite surface plate, or a piece of float glass.

What grits should I buy - I want to sharpen …?

There are no hard and fast rules and many people create their own grit sequence. Here are some suggestions:
Plane Blades & Chisels: 1000 - 4000 - 8000 Grits
Plane blades for Bamboo Rodmakers: 1000 - 6000 Grits
Cutlery: 500 - 3000 - 16000 Grits
Straight Razors: 1000 - 6000 - 16000 Grits
If you are starting with something really dull, the 500 grit stone is an excellent product.

I see you have 16,000 and 30,000 grit waterstones. Are they really necessary?

Necessary? Probably not but many people are interested in achieving the best possible results. We hear from folks sharpening straight razors, cutlery and some woodworkers who feel strongly that the added sharpness is worth the investment to step up to the super-fine grits.

I’m taking a class, What is the best way to transport my GlassStones?

Wrapped in a small towel is a good approach. If you prefer something more elegant, you may want to consider one of the Shapton Set Holders. They store three GlassStones in the base. Flip it over and it acts as a stone holder for sharpening with plenty of clearance for your fingers. Remind us when you order and we’ll include a Shapton Velcro Strap at no charge to keep everything tidy and secure. (Sets already come with the strap).

I have friends with the Shapton Pro stones. How do the GlassStones compare?

GlassStones were developed specifically for the US market based upon experience gained from the original Pro Series. GlassStones differ in that they cut more quickly, particularly in the tougher steels such as cryogenically treated A2 common in Lie-Nielsen and Hock and Veritas blades. They are also engineered to be significantly less costly by employing a glass base. This glass base provides protection for the sharpening media avoiding the need for added thickness and additional packaging found in Pro Stones which adds to their cost.

Why don’t you offer the Shapton Pro Stones?

We believe the Shapton GlassStones will produce the best results at the lowest cost for 99% of our customers. We’ve also found that many current users Shapton Professional Stone are migrating to the GlassStones because they cut faster.

Additionally, there is confusion in the marketplace concerning the Shapton Professional Stones. Both genuine Professional Stones manufactured for the US market and Grey Market Shapton waterstones of a different composition manufactured for the Japanese market are being sold as Professional Stones. Grey-Market stones are not the same product and not warranted by Shapton in the USA. To be safe, purchase only from an Authorized Shapton Dealer.

Originally posted Friday, October 3rd, 2008