What's the rule of thumb on lapping? Can you lap all stones? Do some not need lapping? Should a DMT 325 not be used on certain stones?
When to lap? What to lap?
- Thread starter rickboone1
- Start date
Some stones will need to be lapped more often than others. I can only speak for the stones that I have personal experience with. I lap my King 1.2K and my Shapton waterstones. As a general rule, when they are either A.) clogged/lose cutting power or B.) need to be made flat again from use. However, I do NOT lap my coticule or my diamond stones. Also, I dont know if I would take a 325 to anything finer than an 8K.
Is there a specific stone or type/grit you had in mind?
I had the Naniwa Superstones and they needed to be lapped after every use. My coticules I never lap beyond the initial purchase.
Careful with hard jnats....my oozuka nashiji put up a pretty good fight with the DMT 325 and even wore off some of the diamond plating at the ends. I made sure to keep the plate clean with plenty of water but it happened anyways. I progressed to 1.2K wet paper so far and left it at that for now.
The first stone I did was my carborundum 118 aloxite hone.....the DMT 325 had that rough feeling but after lapping the 118 that feeling was gone, not sure if you should lap an aloxite hone on a diamond plate either.....but at least it smoothed the 325 out.
Both are very hard and I doubt either will need to be lapped again.
The first stone I did was my carborundum 118 aloxite hone.....the DMT 325 had that rough feeling but after lapping the 118 that feeling was gone, not sure if you should lap an aloxite hone on a diamond plate either.....but at least it smoothed the 325 out.
Both are very hard and I doubt either will need to be lapped again.
I do not own one, so I don't appreciate how they work, but why no need to lap a Coticule? I thought most natural and synthetic stones needed lapping at some point. That most everything except a maybe a DMT plate needed to be lapped periodically?
From what I recall coticules are cut to a tolerance that is flat enough. I've never lapped one except for chamfering the edges and even after several uses. If you slurry evenly around the whole stone it wears evenly
I wouldn't use the DMT on a C12K. It will definately lap it, but the C12K is so hard you will probably never be able to use the DMT to lap anything else. Of course, YMMV and all that, but that was my experience.
- Thread starter
- #10
What WOULD you use for the C12K?
I used progression of wet/dry sandpaper on a glass plate on the C12K I had. Mine wasn't all that hard to lap either.
- Thread starter
- #12
So, that one you just lapped once or often?
Depends how much you use the stone and how soft it is (e.g. how fast it wears). You can do a quick easy check with a straight-edged implement - steel ruler, 12" carpenters square, etc. - by just placing its thin edge on the honing surface and checking to see if you can see any light passing between the two...
... or, you can scribble a wavy pencil line on the hone surface, give it 3-5 light-pressure passes on your lapping surface (DMT plate, etc), then check to see if any of the pencil mark is still present. If so, then that portion of the honing surface is a 'valley' or low spot and, if you're looking for a perfectly flat surface, you would lap until no pencil marks survive the pencil test - indicating it now a 'true' surface.
As for a DMT 325, it depends on just how 'smooth' a surface you're looking for as it would leave slight scratches in the surface. Others will disagree but personally, I don't think these would affect the razor edge as they are 'impressions' in the hone surface and therefore make no 'contact' with/have no impact on the razor's edge...
However, I myself happen to prefer a very smooth, almost polished hone surface. When using finishing stones, I know my razor edge is polished and done when suction starts to 'grab' the blade making it much more difficult to move the razor on the hone surface. The presence of scratches would negate this suction and deprive me of my desired/preferred tactile indication of my blade being finished to my liking.
That said, while I've used a DMT 1200 to make quicker work of a Jnat that needed a lot of lapping to be trued, my preferred set up is a $4, 12" x 12" piece of marble floor tile from Home Depot (simply walked it over to the hardware section and put a carpenters square against it to make sure it was perfectly flat before I bought it)... and a couple sheets of 600 grit, 800 grit, and 1,000 grit sand paper (can be found in the body repair section of most auto parts stores). A far cheaper set up than any 8" x 3" or larger DMT I've seen.
Put a couple drops of water on the tile (to hold the sheet of sand paper down), place a sheet of 600 grit on top of the wet tile, add a few drops of water on top of the sand paper, and lap the hone until it passes the pencil test. Then a few quick laps on the 800 grit, followed by a few on the 1k grit just to polish the hone surface a bit (BTW - the 1k grit is actually a bit of overkill and rarely ever needed. Since the sandpaper grit breaks down as you sand, sand paper leaves a much smoother surface than an equivalent grit DMT does.). Last but not least, rinse your hone off well and you're done.
I've used this method on several coticules and jnats and it's worked wonderfully every time...
Hope this helps and sheds a little light on another of the many different methods that can be used to lap a hone.
... or, you can scribble a wavy pencil line on the hone surface, give it 3-5 light-pressure passes on your lapping surface (DMT plate, etc), then check to see if any of the pencil mark is still present. If so, then that portion of the honing surface is a 'valley' or low spot and, if you're looking for a perfectly flat surface, you would lap until no pencil marks survive the pencil test - indicating it now a 'true' surface.
As for a DMT 325, it depends on just how 'smooth' a surface you're looking for as it would leave slight scratches in the surface. Others will disagree but personally, I don't think these would affect the razor edge as they are 'impressions' in the hone surface and therefore make no 'contact' with/have no impact on the razor's edge...
However, I myself happen to prefer a very smooth, almost polished hone surface. When using finishing stones, I know my razor edge is polished and done when suction starts to 'grab' the blade making it much more difficult to move the razor on the hone surface. The presence of scratches would negate this suction and deprive me of my desired/preferred tactile indication of my blade being finished to my liking.
That said, while I've used a DMT 1200 to make quicker work of a Jnat that needed a lot of lapping to be trued, my preferred set up is a $4, 12" x 12" piece of marble floor tile from Home Depot (simply walked it over to the hardware section and put a carpenters square against it to make sure it was perfectly flat before I bought it)... and a couple sheets of 600 grit, 800 grit, and 1,000 grit sand paper (can be found in the body repair section of most auto parts stores). A far cheaper set up than any 8" x 3" or larger DMT I've seen.
Put a couple drops of water on the tile (to hold the sheet of sand paper down), place a sheet of 600 grit on top of the wet tile, add a few drops of water on top of the sand paper, and lap the hone until it passes the pencil test. Then a few quick laps on the 800 grit, followed by a few on the 1k grit just to polish the hone surface a bit (BTW - the 1k grit is actually a bit of overkill and rarely ever needed. Since the sandpaper grit breaks down as you sand, sand paper leaves a much smoother surface than an equivalent grit DMT does.). Last but not least, rinse your hone off well and you're done.
I've used this method on several coticules and jnats and it's worked wonderfully every time...
Hope this helps and sheds a little light on another of the many different methods that can be used to lap a hone.
+1
Unless you are honing hundreds of razors I doubt you will ever have to lap the C12K after the initial lapping.
The C12K doesn't need to be honed very often.
- Thread starter
- #16
I don't even have a C12K, so don't know why I am asking really. I am thinking of getting one. Not sure why exactly. Just to see what I may like about them. I am trying to get an 8k though. Probably C12K too. Who knows.
Most natural stones don't need lapping except to remove damage when you get them (often from use with chisels or something along those lines). Natural whetstones don't seem to swarf up the way that synths do. I don't care enough to try and figure out why but I'd guess it has something to do with natural stones being awesome and synthetics being inferior. That's just a hunch, though.
Coticules of course have the added advantage of being smoothed with every use if you use a slurry stone with them.
I've lapped a handful of China Nats with a DMT 225 with no ill effects. I just scrub and rinse it whenever it starts to lose friction (slurry filling in the grit). Then I switch to wet/dry sandpaper taped on the back of my DMT8EE (or glass, or granite tile) to finish it off.
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