Rolled Bevel vs Micro Bevel vs Hollow Grind

[David Weaver]

I think people differ in their use, here's a couple of examples of what I mean by that:
* I always dry grind my tools right to the edge of the hollow, like the very edge, as in three swipes on a 1000 grit stone brings a wire edge. On a good carbon steel chisel, I almost lament how much metal that will remove, esp. if the stone being used is a semi fresh diamond stone. It literally takes less time to hone off of the dry grinder than it does to put a tool in the tormek jig and take it back out, and the dry grinder time is less during the grinding process.
* I never have water at my grinder unless I'm doing something really heavy. I check for temp and cool an edge by dragging the back flat side on my palm. If I can stop whatever I'm dragging in the middle of my palm, it's not that hot

The other real turnoff of the tormek, aside from the water, and aside from the fact that the black wheel essentially could only be graded by diamonds, and the gray wheel needed to either be refreshed or diamond trued to cut fast, was that the cut speed was never very consistent (you'd love to have it aggressive all the time, but it constantly breaks in like any hard stone, unless you're sharpening something narrow on it, and that just puts lines in the wheel) and putting something like muji HSS on the stone just graded it right down.

Freehand grinding can be just as even as the tormek, except you don't try to raise a wire edge with it, you go just short instead. Not that raising a wire edge necessarily causes temp. problems on a coarse wheel, it doesn't, but it does cause geometry problems because the wheel is narrow.

And, if the purists would look away for a second, I have ground japanese tools on the dry grinder without any issue. I don't do it often because it's totally unnecessary, but I do have a coarsely set funjii plane (an inexpensive but fabulous little beat-around plane that JWW no longer sells) that I use as a jack that gets refreshed either by a belt grinder or a dry grinder.

Certainly for someone who is new, a tormek would be better for japanese tools if there is some large correction to be made or a bulge in a bevel to get rid of or some other such thing.

But, to paraphrase what warren says, if someone has trouble using a dry grinder faster than it's possible to use a tormek, then the dry grinder hasn't yet been mastered.

In this case, a turtle is a turtle. And my turtle is now in a celebrity's shop in virginia.

[Charlie Stanford]

Just to demonstrate that it is all about choices and preferences, and that there are no "right" answers, I am going to disagree with both Charles and David.

I have both the 10" Tormek as well as a 8" dry grinder with a 48 grit white Norton wheel. If one simply compared the speed with which the dry grinder removed steel, the Tormek is not in the running. The Tormek is quicker than most realise when the wheel is clean and used at the lower 220 grit. However, it is still going to hollow grind the steel from a 2" O1 plane blade in about 3 minutes versus the 1 minute for the dry grinder.

The large Tormek also creates a shallower hollow, actually quite shallow - it is possible to hone away the hollow quite quickly. The up side of this is that one can use it on laminated steel without removing the backing layer. One needs to refresh the hollow after about 4 or 5 honings, but this is quick thanks to the angle setter, and the only steel removed is inside the hollow, not from the length of the blade.

So far the dry grinder seems to be the winner. However, there is another factor, and this is where the Tortoise overtakes the Hare.

The Tormek, being a wet grinder, runs very cool. You can grind to the very edge of the blade without fear of burning the thin steel there. You can also hollow grind laminated Japanese blades without fear of affecting the hard steel layer. By grinding to the edge, it take one or two passes on a 5000 or 6000 grit waterstone to create a micro bevel. It takes about 5 passes on a 13000 waterstone to complete the polishing stage. And you are ready to go. This process takes about 30 seconds.

On a dry grinder one would have to stop about 2mm from the edge to avoid heat damage. At this point you need to begin with a 1000 grit waterstone to create a larger micro bevel (not sure it it is a "micro" bevel any longer), and I'd estimate that this takes about 2-3 minutes. And then you still need to move to the 6000 and 13000 stones, each of which takes many more passes than on the primary hollow from the Tormek as the primary bevel is wider.

Furthermore, the hollow grind on the Tormek is controlled by the guide, and it ends up being very even in width. The hollow on the dry grinder tends to be made freehand. I am quite decent at this, but still end up with an edge that needs to be straightened on the 1000. This adds to the time in preparing the final working edge. Remember, it is the time in achieving a working edge that determines the speed of the machines, and in this manner you will find that the Tormek is the faster machine overall.

Lastly, a further advantage of a clean hollow is that it makes it easier to freehand if, as I do, one uses the hollow as a jig. Grind the hollow primary at the angle desired, and freehand directly on this. Quick and easy. But not for everyone.

Regards from Perth

Derek

On the bit about not grinding to the edge... well, you need to be able to grind at the edge and not burn steel. One will grind at the edge, immediately, if raising the grinding angle of any particular cutter. A clean wheel, light touch, plenty of quenching make this mostly a non-issue. On a day in and day out basis, sure, stop a little short and wrap up at the stones. One never grinds all the way to the edge, anyway, if just restoring the hollow. All you really need to do is "squeeze" the honing bevels at the heel and edge back to a reasonable size - this is the definition of refreshing the hollow.

[dan sherman]

how do you all feel about belt grinders? I have considered building a 2" x 72" one, and making a custom honing guide like a Kell, that would slide onto a Tormek style rest. This would alloy you to set the tool in the guide go to town on the belt, and then strait to the stones with no fuss.

[David Weaver]

A common belt sander would be what I'd use for a nick. It always rounds the blade a tiny bit, but it's faster than any grinder that I've used, especially with a fresh belt. serious nicks in an edge are few and far between, I can't remember my last one, but I'm pretty sure that the last couple of times I nicked an edge, it was more of a hangar rash type of incident, or accidentally (like something loose on a hard stone) and not from use in woodworking.

[David Weaver]

(about the big belt grinder) If you're going to use a grinder that big on edge tools, I would personally want it to be variable speed. If it is, you can do anything those, from bevel refreshing to serious heavy grinding. At full speed, the belt speed is really high, though, thus the want for variable speed.

[Charlie Stanford]

Good advice. The sander can be used for other stuff too.

[Tony Wilkins]

Just want to pop back in and say that I appreciate all the different points of view expressed in this thread. I have learned a lot from both Charlie and Derek over the last year when I've been trying to get off the ground in the hobby. As well as many other folks such as David Weaver, David Barnett, Chris, and many others I'm forgetting.

[Jim Koepke]

My only comments in this thread so far were based on my curiosity about the possibility of how a convex bevel may actually improve the function of a mortise chisel and something recalled from reading about the historical/philosophical reasons behind Japanese woodworking.

Most of the time my shop equipment limits me to having a flat bevel. This is due to not having a grinder capable of making a hollow grind.

My thoughts on this are for people to work with what they have and to find what works best for them. If one can get their tools to work for them, it doesn't matter what anyone else thinks of how you got there.

So far my methods work for me. It is always interesting to see what others are doing with an eye toward gleaning tidbits of information that may help me to understand the process better or to improve what transpires in my shop.

As Derek said, "there are no 'right' answers."

There is a multitude of useable information available which we must distill into our own answers along the way.

jtk

[David Barnett]

how do you all feel about belt grinders?

I love belt grinders. While I enjoyed the incredibly versatile 2" VS Wilton Square Wheel for years, it was overkill for most I now do so passed it along. While I mostly use an 1800 rpm 7" Baldor for chisels and planes, I use a 1"x42" belt grinder for carving tools and just about everything else. It's terrific for making & maintaining hand tools, woodworking and otherwise. Wouldn't want to be without one.

[dan sherman]

(about the big belt grinder) If you're going to use a grinder that big on edge tools, I would personally want it to be variable speed. If it is, you can do anything those, from bevel refreshing to serious heavy grinding. At full speed, the belt speed is really high, though, thus the want for variable speed.

If i build it, it will be variable speed for sure. Something like a 3 phase 1hp coupled with an appropriate VFD.

[David Barnett]

If i build it, it will be variable speed for sure. Something like a 3 phase 1hp coupled with an appropriate VFD.

I do like the KMG grinder and clones, especially with the rotary platen attachment. Yeah, every since letting the Wilton go (I 'loaned' it but will never ask for it back), I've wanted to build one of these, if only for fun. And 3 phase would be nice, and David's right, you gotta have VS.

Kind of a handful for the home woodworking shop just to sharpen hand tools, but...

[dan sherman]

I do like the KMG grinder and clones, especially with the rotary platen attachment.

Jesus those things are over priced, I'm pretty confident I could design what I want for less than $500 maybe less than $300 depending on what type of deals i can find on the components. for one thing I don't thin you need a 2hp + motor. We are sharpening tools, not hogging away chrome molly tubing. I also don't thing we need the 5000 sfpm max that some of these machines have.

[David Weaver]

Jesus those things are over priced, I'm pretty confident I could design what I want for less than $500 maybe less than $300 depending on what type of deals i can find on the components. for one thing I don't thin you need a 2hp + motor. We are sharpening tools, not hogging away chrome molly tubing. I also don't thing we need the 5000 sfpm max that some of these machines have.

Thus my comment about VS. 5000 feet per minute and a little bit of pressure against a hard platen will turn a tool edge orange in no time.

I don't have a big grinder, just 2 1x42 grinders, well, one now and one that doesn't work. Anyway, nothing I have in my shop will burn an edge faster than the viel tool grinder would with a trizact belt and a platen.

[dan sherman]

Thus my comment about VS. 5000 feet per minute and a little bit of pressure against a hard platen will turn a tool edge orange in no time..

I'd do something like this, minus the solid stainless construction, and the 9000 SFPM top end.

https://www.youtube.com/watch?v=UKZI-Bm_Eyw

[Adam Cruea]

I'd do something like this, minus the solid stainless construction, and the 9000 SFPM top end.

https://www.youtube.com/watch?v=UKZI-Bm_Eyw

That thing sounds like it's got more chutzpah than my TC88 Softail.