Thread: Lapping stones

I haven't had any issues with lapping the Naniwa 12K I have using a DMT325. I just pencil mark a grid and then do figure 8s under running water.

Originally Posted by onimaru55

SiC grit slurry on float glass will eat Arks for breakfast. It can be purchased in very low grits if needed.

Lol, let's rephrase that... It will eat small Arks for breakfast. Try flattening a 3" X 10" translucent black and you will change your tune PDQ! The larger stones get mostly flat pretty quick, but that last 10% of surface area seems to take about 90% of the lapping time.

I did an 8x 2.5 trans black arky a few years ago.

I tried wet and dry and it was working but slow.

Loose grit was faster.

Diamonds are also fine.

The fastest method was a big paving slab and 80 grit dry wall mesh.

Silverline Plasterboard Rust Removal Hand Sanding Sander Mesh Roll 5m 80 Grit - Sander Belts - Amazon.com

Long length of it over a paving slab, and tucked in over the edge. Then you just work in big long strokes to get the rough work done. After than I did a diamond progression under water.

The trick is to go past where you need to on the coarse grit, so you get all the low spots off. If you leave a low spot with the intention of been able to get the finer grits to grind down to it then you will be there forever. So grind more than you need to on the mesh, then just tart up the faces with diamonds. And finally burnish out. Once it's done it should be good for many years.

Arkies are very hard stones tho, For everything else a diamond plate is very much the perfect tool.

The 8x3 DMT that everyone harps on about is one of the best solutions. There are other manufacturers making similar plates at that size.

If you are really short on cash the wet and dry option is perfectly valid, and you can scrape by on one of the better 6x2 diamond plates. Am-tech make a reasonable one provided you check it's flat before use (they don't tollerace the plate anywhere as closely as DMT do). At 6x2 you will have a few problems getting your fingers on the plate as you work it. Just make sure you have a stone that is free of loose grit when you use wet and dry as any that gets stuck in the stone will cause you problems if you don't notice them.

You want to avoid the cheap plastic backed diamond plates and cheap diamond 4 sided blocks. They bend and warp with use, and are not flat in any way shape or form.

Actually getting a stone flat isn't hard work most of the time. It's a few minutes when you buy the stone, then a few seconds when you actually use the stone. You should not be removing significant material, and you should not need to flatten for every razor. My naniwa super stones get a quick lap every few razors, Just a pencil grid and a quick rub till all the marks are gone.

Originally Posted by Della

I have 300-400-600 & 1000 grit wet/dry sand paper. Also, have a naniwa lapping stone and a DMT 325 on the way. What is recommended for lapping a Naniwa 12k finishing hone, as I have heard that the 12K doesn't like the DMT325??????

What you *may* have heard is that fine hones like the Naniwa 12 AND other finishers may not like a brand new DMT 325 as there is likely the errant diamond that sticks up further than the rest when brand new, thus causing scratches in the surface of the finishing hone. I don't believe this to a problem, it is just *air* to a razor running across the surface.

If you wish to break in your DMT, it's common to run something like an old screwdrivers shaft across the plate gently, just to knock the high spots off. The reason for a on old screwdriver is likely that even a cheap one will have fairly tough steel that will catch the errant diamonds and take off their excess height. You could use a knife, old hacksaw blade (the back edge, not the teeth), lawnmower blade or what have you... it's just likely you have an old screwdriver lying around that you won't miss if it gets a flat ground into the side of the shaft. But... it does need to be straight! One that's bent is not going to be easy to use.

I broke my DMT in by trying to flatten a couple of barbers hones.... they were tough buggers and my diamond plate is REALLY smooth!

Do a search for breaking in a DMT 325 and you should find several threads.

Regards

Christian

Actually I disagree there. It's not just air - the sharp pointed deep scratches also leave sharp pointed peaks when they are close to other deep scratches - which leaves a pointy weak fragment just waiting to break off while honing. When this happens, loose abrasive particles are rolling around under the steel, leaving much coarser scratches than would be left otherwise. A worn-in diamond plate doesn't cause this issue, but the issue caused by using a new sharp diamond plate can be mitigated by merely running another piece of steel over the hone for a minute or two to remove any peaks immediately after lapping, then rinsing and wiping under running water to remove any loose abrasive.