Thread: Scratch marks in stones after lapping

I'm getting ready to start keeping my razors in shape, and I've got a Naniwa SS 5K, 8K, and 12K. I also got a DMT 325 plate to lap them. I got them through SRD. So, I thought I would lap each stone as that seemed to be a pretty standard recommendation, and I figured it would have to be done at some point anyway.

After lapping them with running water and using a figure 8 type of pattern, I am noticing that there are scratch marks on the tops, and the tops of the stones where I've lapped them do not feel as smooth as the bottom of the stone that I haven't lapped. Please, please, please tell me that I've not just ruined the entire set up.

I think 325 is good for removing a lot of material quickly. I usually go up to 1200 lapping. That leaves a non scratch surface. However lately, my worn coarse DMT 325 has been leaving a polished finish. Maybe yours is not broken in yet...

Your stones are not ruined, take a screwdriver or a heavy cleaver and use it to knock down the high diamonds on your dmt, they need to be nicely worn down first, after a while they will. Leave a grist fins on your stones.
Plus the low spots from a high diamond won't affect your edge only high spots, not to mention you still have the other side too. So your fine. Tc

Everything is new, so I would assume that my DMT 325 is not broken in yet. What do I do in the meantime? I am guessing that I should not try honing on the stones if they don't have a non-scratched, polished finish.

I thought that I would be good to go right away running the DMT over the stones a bit.

Just do as TC recommended and knock the high diamonds down. It does not take a lot of effort or time to do. Then relap your hones.

Bob

That happened to me the first time I used my DMT325 and I thought OMG I ruined my homes. It is common enough with DMT325s that there are a few threads on it here.

Or, you could go outside and hone the sidewalk for a few seconds at a time. Even a red brick....

Seriously!

I agree with the above comments. A coarse DMT would leave some scratches and needs to be broken in. Just sharpen up all you kitchen knives and anything else you can fine. ahaha.

As for lapping in the meantime and with finer grits, for many years I used a 12-12" granite floor tile from the hardware store and some wet dry sandpaper. tape it down and have at it! Works great. Just be sure to clean the hones very well to avoid grit contamination. Now I use DMTs 250 to 1200. But I wouldn't hesitate to use the tile method again. Saves having to wait to break in the DMT and saves you buying more DMTs for a while if you don't want to.

Furthermore, Scratches wont hurt as long as they don't "catch" the edge, as said above

Imagine a bed of nails. You can lie down on it because the nails are all of the same height and so the pressure is uniformly distributed. Now imagine the different effect if one nail stuck up a half inch higher. That nail would hurt.

The advice above is right because of a similar problem caused by high diamonds. If all the diamonds were the same height, they would cut uniformly and leave a smooth surface. If a few diamonds are higher, they are going to cut into the hone deeper and will leave scratches.

To summarize: take an old screwdriver, socket extension, or any other straight piece of steel, spray some water on your DMT, and rub the steel back and forth over the surface for a bit - refreshing the water as needed. This will break in your DMT, you will be able to feel the difference as you do this. When done wash all the swarf (steel and diamond bits) from the DMT and relap your hones.


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Feeling much better! Thanks all!