This post is based on lapping a natural Coticule and Belgian blue only.
When you purchase a coticule (or BBW) from this store, you will overtime need to ensure it stays flat for the best results, (just like all whetstones of all kinds) so it does not dish.
Coticules and Belgian blue stones will stay flat for a long time with just regular use, however I do recommend to straight razor users to lap the stone before using it for the first time (they may not always come completely level from the factory) to ensure a nice flat/level working surface for your razor. You will need to do this process over the life of your coticule/BBW stones anyway, so starting upfront is a good idea. Lapping and whetstones go hand in hand – this you can’t avoid regardless of the stone you use (any brand etc.).
The below guide lists a couple of methods to do this process! You may choose an alternative however.
What Is Dishing?
Dishing is simply the process of a whetstone slowly wearing away at the point of most contact with the blade (most common area on a whetstone for dishing is right in the centre, the place we usually focus our passes most). Over a period of time all whetstones / water stones will begin to get dishing. Whetstones break down overtime – this we cannot avoid!
This dishing of the stones surface can happen on both natural and synthetic stones. However, synthetic stones are most affected and the courser grits are most affected within that group. I have found that the natural Arkansas whetstones are least effected of all the stones.
How Often Do You Lap A Coticule Whetstone To Prevent Or Correct This?
Lapping is done on a fairly regular basis. Some do this before each and every sharpening session (for coticules and BBW stones I think this is too often however, as they do not wear that quickly).
This regular lapping has benefits:
- Will keep the whetstone constantly flat for best sharpening results.
- It is much easier to lap a stone that is already quite flat.
- Allowing a stone to dish too much, makes the process longer and in turn a courser lapping stone/plate will be needed to bring it back level (remove the high points).
Like most tasks, keeping on top of this process will make it easy and quick!
If you looking for the easiest way of lapping / flattening your stones, please see ceramic lapping stone, or the diamond plate. Either of these combined with water will do a very good job easily and quickly.
A slightly more messy way is to use:
One method of lapping is to use wet and dry sandpaper on a level surface. Using this method, draw lines across the surface of the stone with a pencil as seen in the photo. This part of the process won’t be needed for the BBW stones however, as the darker BBW stone will hide the pencil lines, making them too hard to see.
Now with some wet and dry sandpaper of approximately 320 grit placed on a flat and level surface (and with plenty water flushing the surface throughout the process to reduce clogging), simply rub the stone over the wet sandpaper.
When you see the pencil lines all evenly disappearing / and then gone, you are near flat. Ensure the surface you place the wet and dry sandpaper on is of course level or you may cause more unevenness!
Wash and rinse well with more water when done, and you should now have a nice flat coticule ready to use.
Diamond plates are a very popular method of lapping whetstones (synthetic and natural) due to their very level nature (assuming the plate is of quality). They also provide a good cutting speed when lapping to make the process quick and simple. For lapping Belgian stones 320 – 600 grit is the usual standard.
Diamond plates are also the go to for the harder synthetic stones like the Shapton stones sold here. More on the Shapton lapping here.
Always use water to flush/rinse the stones/plates when lapping!
For general lapping duties of any whetstone, you will find some whetstone manufacturers make lapping products for their whetstones. If this is the case, they are a good place to start.
Belgian stones do not come with specialized lapping stones and why the above methods are listed. Always follow manufacture directions regardless of the diamond plate you purchase for this duty, to ensure the best result – and if unsure ask them.
Lapping Also Removes Swarf Build-Up!
What is Swarf? Overtime as your tool / blade begins to wear down from the sharpening process; you will notice a black build-up on your whetstone. This is called swarf (steel shavings/particles). Coticules and BBW stones do not suffer from this issue to any real degree – however this is still a possibly on other stones and therefore mentioned.
Swarf on the stone
It can begin to clog the whetstone and will also need to be removed regularly. Water flushed over the stone throughout the sharpening process, will not be enough to stop this swarf build-up overtime (it can get into the surface).
Slurry stones can also remove swarf, but are too small for regular lapping duties.
Regardless of the whetstone being lapped, for best results use a lapping stone/plate that is the same size or larger than the whetstone you are flattening. If you use a smaller stone you have to ensure you fully move it up and down (and circular movements from corner to corner) to ensure even and equal surface coverage. Again, if this isn’t done evenly across the entire surface, your lapping stone/plate will actually cause further dishing and unevenness.
Do Lapping Stones Need Replacing?
Yes, lapping products regardless of the medium used or product cost $ will over time need to be replaced (but very rarely in the case of diamond plates) simply because they too, wear down overtime. As they are wearing down the whetstone, in return they are being worn also.
Will This Process Make The Whetstone Surface Course?
Usually lapping is done with courser grits to the whetstone itself, so after lapping you may notice for the first few sharpening sessions the surface is more course than usual. This will wear away. Or to speed this up, use a slurry stone to help smooth the surface.
Just like you need a whetstone to sharpen a tool; your whetstone needs a flattening stone to keep it functional also. If you don’t flatten the whetstone with one of many possible available options for this task, your stone will not be as use-able and produce poor sharpening results.
The main rule here is to ensure the product you use to lap Belgian stones with is flat/level itself. If not, you are literally trying to flatten an uneven surface with another uneven surface and this will not produce good results. The principle of the exercise is the same regardless of the ‘brand/product’ used.
Disclaimer: This is strictly a guide only, it is not presented as the only way, or necessarily the most effective way to lap a coticule; nor is a perfect result guaranteed or implied.