Thread: DMTs & does anyone have a micrometer?

Originally Posted by Sticky

The great joy of having flat hones is that you can go from one hone to another without being forced to re-establish a new bevel on each hone. Flat hones will also give you a much faster sharpening job, assuming your workpiece/razor is also relatively flat.

A hone that is moderately flat in the spine direction can be heavily dished in the long stroke direction, and give nice edges (using an X-stroke). As long as that particular razor stays with that particular dished hone. As soon as that razor sees a flat hone, you'll be working a while on the "new" bevel. Hence the popularity of a flat hone. Maximum portability.

Excellent point. You know your stuff, Sticky! It makes perfect sense that a flat hone will give a much faster sharpening job for the simple fact that.....more of the blade is in contact with more of the abrasive!

A Shapton rep I spoke with today did nothing for me other than pour gasoline on my HAD (and a disorder it is!) by answering all my questions and making me ga ga over the diamond on glass plate flat within .5 micron across its surface. Shame on him!!! He painted a good visual: If the abrasive on a specific hone is .5 micron and the variance across the surface of the hone is .5 micron, then on a pass, the edge will be in contact with only 50% of the abrasive. I'm not quoting him directly and I may have skewed his explanation; hopefully not. His point was think of the difference between .5 micron variance and .001" variance.

I admit, our discussions here and others like it are over analyzing this issue to an absurd degree. I'm not saying HAD is good, maybe HAD is bad. I have HAD.

I was thinking about the following as a possibility for me:.........Sell off the DMT 325, 1200 and my Norton 4000/8000 and go with the Shapton Diamond on Glass lapping plate (replaces the DMT 325), getting a Shapton ceramic on glass 1000 grit (replaces the DMT 1200) and run with that setup along with my belgian blue and yellow coticule.

Maybe someone can offer me counsel, give me a few slaps on the face and tell me to snap out of it. Please someone, help alleviate my HAD!

Give you counsel about your HAD? Ha! Fat chance!
Not until you have more hones than I do. You have 200 more to go!

Beats drinking,

I'm looking for my Tormek manual, there was some mention of the issues of using the round 10" stone on the Tormek for sharpening the bevels of chisels. In use, the bevel is used to support the edge in the cut and those who swear by using flat hones for sharpening claimed that the "deep hollow" would cause loss of control in the cut. My math is rusty so I can't just whip up the numbers but on a typical chisel bevel, the hollowing only amounted to about 1 thousands of an inch or so... It's there, you can see it with the naked eye etc. but in practical use it's not an issue. Considering the width of even a well worn razors bevel is far far less than that of a typical chisel and that the kind of dishing we're talking about on a flat hone is so much less than the profile of a 10" grinding wheel I can't really see how a few thousands of an inch dishing is going to make much of a difference. It DOES make a big difference when polishing large flat bevels with a very fine stone such as chisels and plane blades, but I don't see it on the minuscule bevels of a straight razor.

Oh well, enough theory for tonight.... I need to go shave.

Regards

Christian

Originally Posted by randydance062449

Give you counsel about your HAD? Ha! Fat chance!
Not until you have more hones than I do. You have 200 more to go!

Beats drinking,

I was going to say something like that, Randy. Thankfully it beats a lot of things. 200 Hones!

The thing that makes me a fan of the DMT hones is their versatility. You can use them for other stuff around the house. Once you get used to the Belgians, I'll wager you won't use the Norton much. Bruno's about the only guy to use Belgians and switch to a Norton. And he's from Belgium!

Josh

I like DMT so much I'm gonna' convert to all DMT except for one finishing hone. I might even put 'em in my avatar....

We need a "DMT brotherhood."

Josh

This is how the radiused edge mathed out:

• Assume a bevel width of around 0.015" (my razors average around 0.008" to 0.015"). Assume a radius of 12' to 24'. The distance from the radiused bevel surface to getting the bevel flat maths out to under 1 millionth of an inch (97 nanoInches to 200 nanoInches).

I would say that any flat hone following a dished hone is cutting the curved radius off to a flat so rapidly that it isn't, in most cases, a practical issue. The info on using a dished Belgian (or any hone) is extremely interesting.

My real worry with dished hones is that changing the spine angle (e.g. to heel leading/trailing) during the stroke will wear either the heel or tip unevenly? I was thinking the operator would have to be extremely consistent to avoid it. Is the dished out portion consistent? It's just so easy to make most hones flat, that I can't see any reason not to do it. Flat avoids all kinds of potential problems. For a new fella' like me anyway.

Originally Posted by Sticky

. Flat avoids all kinds of potential problems. .

Yup! What he said!

When a surface is flat to .001, that is the specification for its flatness. It's not "off". If you want to get it to .0001, you can do that but it will cost a lot of money. "Flatness" is just a question of money. Look at your friend's surface plates or better yet, look them up online in the Starrett catalog or MSC or Enco. You'll see that as they go from Grade A to B, they're certified at lower levels of flatness.

Flatness is spec'd to the performance requirements of the tool. I don't believe that going beyond .001 will result in a better shave. Your face varies a whole lot more than that!

I have a bunch of new digital micrometers in boxes if anybody wants to start measuring their stuff.