Thread: Breaking in a DMT.

I just ordered the D8E ( Along with a coticule) from the perfect edge.I read somewhere that you have to" break in" the D8E before you use it as a bevel setter on a razor.Could anyone please explain how?

Kristoffer.

Yeah, the DMT8E is pretty harsh on razors before being broken in. I took a very old, very large screw driver shaft, and did about 500 laps with it. Then I lapped a swaty stone, then sharpened all my kitchen knives. All of that still wasn't enough. The DMT was still pretty harsh.

A few days ago, I took my Chinese 12k to both of my DMT's to further break them in. 15 minutes of "lapping" the chinese 12k (which is a very hard stone) did a great job of reducing the DMT's harshness.

So find something really hard that you can rub your DMT on until it isn't so harsh.

Ok, thanks.Finally I have found a use for my chinese...

I bought a DMT from Howard as well, and it took quite some time to see any effect on the razor, so I asked him what could be wrong. Aside from a discussion of details on what I was doing exactly, he asked me whether I had broken the DMT in. I hadn't even heard that before, so I asked what it meant and how to do it. He explained that out of the factory the hones had a thin layer of nickel plating for protection which had to be worn out by rubbing a piece of steel. After I did that, the process of honing indeed did speed up.

These point to the contrary of the purpose being removing excessive harshness. Intuitively, I feel if such a small time of abrasion could perceivably reduce the harshness of these hones, then they wouldn't last very long under professional use, which honing a razor every other month or so isn't. As far as I know they are very durable. Also we are talking steel vs. diamond.

What am I getting wrong here?

Like FloorPizza I took the shaft on a 12" Stanley screwdriver and after wetting the plate I did some round trips on the flat part and on the edges. I used a fair amount of pressure. It doesn't round the edges but it knocks down any divots that might catch the edge of your razor or knife if you use the DMT beyond lapping.

Had I read the instructions before using it I would have put a drop of dish washing soap on the plate. They suggest this and it does make it work more smoothly. kuoytfouy, you probably won't wear that plate out in 20 years.

Originally Posted by JimmyHAD

kuoytfouy, you probably won't wear that plate out in 20 years.

I'm not concerned about wearing it out, on the contrary. FloorPizza said (backed by his experience) that the purpose of breaking in is reducing harshness, while Howard's instructions (if I didn't misunderstand) and my experience suggest otherwise, i.e. breaking in removes a layer which blocks actual abrasive particles, thereby increasing abrasive effect (does FloorPizza mean something else by harshness?).

So I wonder what exactly is going on.

I never heard of a protective layer of nickel over the abrasive diamond particles. My impression is that they are embedded in a layer of nickel on steel. I was wrong once before though.

I believe you can just take a DMT and go with it if you are sharpening plane irons, chisels and the like. Naturally with the paper thin edge of the razor some break in is beneficial. Here is the DMT FAQ .

yes, "over" was an inaccurate word. Anyway, what you are saying is to the same effect.

I'll check that FAQ, thanks.

Originally Posted by kuoytfouy

I'm not concerned about wearing it out, on the contrary. FloorPizza said (backed by his experience) that the purpose of breaking in is reducing harshness, while Howard's instructions (if I didn't misunderstand) and my experience suggest otherwise, i.e. breaking in removes a layer which blocks actual abrasive particles, thereby increasing abrasive effect (does FloorPizza mean something else by harshness?).

So I wonder what exactly is going on.

Yup, he does.

Until they are well broken in, the DMT's have a tendency to microchip harder steels, as well as make very deep "V" shaped scratches in the blade, as well as uneven (some scratches deeper than others). Bart has talked about this quite a bit, and can explain it better than I can. Anyway, the edge left by a broken in DMT has scratches that are more refined, even, not as deep, and with less of a "V" shape. The result is a smoother blade.

I got my DMT D8E today. Started by rubbing a steel tube against it for a while to break it in a bit, but didn't do it too much. Used it to lap my Norton flattening stone on both sides, then another cheap hone (I believe it is a 400 grit, yet it is sold for razor sharpening lol.)

Figuring I had broken it in enough I started lapping my Norton 4/8K. I noticed a dark patch appearing in the middle of the Norton. I thought it may be graphite from the pencil marks collecting, so continued. Got both sides so smooth it was hard to stop it from aquaplaning while lapping, but the dark patches remained. On the yellow side a scrubbing brush removed most of it, but on the white (4K) side I couldn't get it all out.

SO, the questions are, what is causing this mark, and is it a problem? Could it be nickel coming off the DMT surface? Should I try to remove it and how? I can't do it by lapping because that's what's causing the problem! Unless I use the Norton flattening stone again, which would be kinda dumb as the DMT is undoubtedly flatter.

Any ideas?