Sharpening, yet again… *LINK*

Video two *LINK*

john jesseph

Ken is a guitar builder. I’m not personally familiar with his work, but it seems innovative.


Second Video

Part Three *LINK*

john jesseph

Food for thought. I’m not advocating it, and the horizontal waterstone wheel is one method not on my list to try. I’m going to check out his edge tool and gouge videos.


Third Video

Re: Sharpening, yet again…

john jesseph

I didn’t really make it through the first video, but I’m curious what he finds so useful about the Makita machines. I heard some people like them to flatten backs. Probably works well enough to just get on with making guitars…

Re: Sharpening, yet again…

eliot feldman



I do something similar to this guy. Not a Makita but a Veritas for horizontal power sharpening. Or the CBN wheel for the bevels and the superfine Spyderco ceramic stone ( 3 microns) followed by that green stuff on a planed wooden support. The CBN + Spyderco + green stuff I learned from Derek. Lately, I've been fooling around with very fine diamond films. but some say I'm overdoing it. When using the Veritas power horizontal method, you don't get a hollow grind, which of course results from a wheel. The final polishing disk for the Veritas is 4 microns; this disk is a few millimeters thinner than the other disks so you get an automatic micro bevel. The last photo shows a Japanese chisel using the Veritas equipment. It would look the same had I done it starting with the CBN. It's pretty sharp.

Re: Sharpening, yet again…

Steve D, in CT

Way back when I got Delta's response to these Makita grinders. Other than a red waterstone they are very different and seeing the Makita increases my regrets on the Delta.

The attraction is that you have a cool wet power grinder and in the case of Makita or Tormek the downside is speed. Delta, not being satisfied with a slow process, added the dimension of huge mess by running the wet wheel too fast, lowering the mud shield below the wheel surface and not recycling the water like the Makita appears to do.

The wheel looks like a King 1000 or 800 in circular format. There is a fair amount of mud that piles up on one side of the tool - part of the mess. The Makita looks like the wheel is submerged and would keep any slurry from forming, for better or worse.

For someone who likes Japanese blades and flat bevels the Makita could be useful prior to fine sharpening. I didn't realize how widely the Delta misses the mark. If I wanted to power sharpen my Japanese tools I'd consider the Makita but I'm not trying to beat the clock.

Re: Sharpening, yet again…

eliot feldman

I'm surprised you said that one of the down sides of this Makita is speed. I don't have one, so I really know nothing about it, except what I saw on the video. But it looked really fast to me -- not slow at all. I like my Veritas --except the guide that sets the tool to the correct length is kind of a pain: things slip around while you're trying to get it just right. I called Veritas( or is it Lee Valley you have to call?) about it. They didn't want to say there was a problem, but they seem to know about it because they sent me some kind of tape that you put on this guide that keeps things from slipping so much. It's still a pain but a bit less so. But the system I like most it the CBN wheel fitted with the Tormek guide rail and their tool holding clamp. It's supper fast and extremely friendly and accurate. As I say, I learned it from Derek.The funny thing is that even before Derek put me on to it, I already had not only the CBN wheel but even the Tormek guide setup. I had been using these for sharpening turning tools , and I was too slow in the head to think of using it for flat work. But I do now. and it really is a superior method.

Question

Bill Tindall, E.Tn.

I dismissed this tool when it was introduced because it seemed to have a flaw. The rate of material removal will increase with the distance from the center of the wheel. It seemed it would have to create bevels.

Does it, and if not, how is grinding a bevel avoided?

Re: Question

john jesseph

That 8 percent difference in theoretical abrasion based on radius could easily be offset by varying the location and amount of pressure.

I find it interesting the techniques that professionals gravitate to. The Makita grinder as sold and designed seems to be used at a tangent or cord line, perpendicular to the radial direction.

I also found the horizontal polishing wheel interesting.

Re: Question

eliot feldman

In your honor I got a small Stanley block plane iron right out of the box to do a little test. The iron still had machine markings from the factory, but it looked very square all over. The bevel-edge out of the box was 30 degrees. I used the Veritas with the second coarsest abrasive for about ten minutes on and off. The truth is that it did indeed grind a bit more on one side -- but to my surprise, it was the INNER edge that had a bit more grinding. By 'inner' I mean the edge closer to the center of the grinding disk. I had to apply a little more pressure on the outside of the iron to even it out. I went down to the finest "grit" -- 4 microns,and found the same pattern, which also evened out with a bit more pressure on the outside. It has a beautiful polish very even across the width of the iron now that I applied a little "English". The moral of the story, I believe, is that there are several other variables besides disk radius involved. For example the exact angle of the iron in it's holding clamp; whether or not the tool holder is perfectly parallel to the disk; etc. Slight variations in these other variables are apparently more significant than the effect of the radius difference, which of course theoretically should cause more grinding at the larger radius because of the higher linear speed. The machine works, but like so much else, there are these little quirks. I believe the CBN with the Tormek guide and tool holder is the best way to go if you are going to use power. I use the 180 grit CBN wheel for this purpose. There is no question that Derek has the clearest presentation about it.

you do good experiments

Re: Sharpening, yet again…

Steve D, in CT

Relative to the speed of your CBN wheels it would be slow. Also, I have the Delta version which may be slower than the Makita. Notice that when he bore down on the back of the blade the motor slowed quite a bit.

I only watched that one video but his combined process was pretty quick. A faster grind may save a little bit of time but need more cleanup if the scratches are deeper. Dunking tools in water to cool them isn't very fast either.

Re: Question

Steve D, in CT

If your blade is clamped in a guide that will prevent any difference from part of the disc going faster than the other. Your difference is due to being slightly off in the clamp or the clamp not making contact on both of the contact points with the guide rod.

CBN and Worksharp 3000

john jesseph

I have a Worksharp 3000 boxed up ready to sell on eBay. I bought it back when one of the online retailers mid marked the price to a ridiculous low price, and a bunch of Badger Pond denizens piled on and bought them.

I’ve never used it for much of anything, but I’m tempted to buy a cbn disc and experiment with back flattening. I have no patience for fettling currently, and this might help.

Re: you do good experiments

eliot feldman

There is one more thing: Granted that the linear speed of a point on the disk is greater as the radius

increases, remember that the blade can be sharpened on either side of the disk center point. ( Of course on one side, the abrasive grinds into the edge; whereas on the other side it grinds away from the edge.) So to the extent that the grinding action is greater depending on radius, it can be exactly compensated by switching to the other side -- unless, for some reason, there is more or less grinding done because the abrasive moves into or away from the edge.

Re: Question

eliot feldman

I not sure you are picturing this thing right: There is no way to clamp the blade into the guide so that part of the edge is not meeting the disk at a radius different from another part of the edge. This feature, which was of concern for Bill, is inherent to the geometry of this Veritas disk sharpening system. I can imagine a disk grinding setup wherein the edge of the blade is kept TANGENT to the radii. But that's not the way this Veritas is designed.

Radius

Jack Dover

Usually one doesn't put a tool parallel to a radius - most probably a disk will jerk and pull a tool off a hand. A better placement is more or less tangential to a disk.

This being said the WS does create back bevels, even on medium grit - 320-400 it will put a pronounced back bevel over the whole area of contact. Or in other words it will remove considerably more material at one end. Probably because it's really hard or impossible to create even pressure. Naturally users tend to put more pressure at the business end of a tool, and there it removes more steel.

Not that it makes a tool unusable. I kinda adjusted myself and this little thing got me out of many hours of manual lapping, it earned its keep many times over those 35$ I have paid for it new. I'm yet to try a slotted wheel for carving tools, that was promised to be its best purpose. But if I were to buy it again - I'd buy a similar device from LV, because WS clearly needs a few more iterations in terms of design and engineering. Or maybe wouldn't buy it at all, thanks to your articles I'm at better terms with a regular grinder, so the yellow guy is collecting dust these days.

Re: Question

Steve D, CT

It the blade is jigged properly it won't matter that the abrasive is working faster on one end of the edge than the other.

A surface grinder uses a wheel narrower than the work piece so that part of the piece being ground has full speed wheel grinding it and the rest of the piece has air, with no abrasive properties. Because the piece is held in place it grinds evenly.

In the absence of a jig, paying attention and applying pressure biased toward the slower part of the disc should work. I haven't experienced any significant issues with the sides of disks.

Re: Sharpening, yet again…

Charlie

Looks fine to me. I'd say the proof is in his output, which appears to be quite impressive. Plucking things out of context and "shop flow" is where things start to run off the rails. The grinder is certainly no surprise. Those things have been around forever and I think Makita still makes them. They wouldn't make them if they didn't sell.

If his methods strike a chord with you that's great. You could do a hell of a lot worse than emulating somebody who practices his craft as a professional and at what appears to be an extremely high level.

Re: Question

eliot feldman

I believe the picture shows that there is no part of the blade that sees air. The chisel is in a jig, but that doesn't prevent the entire chisel edge being held flat against the surface of the grinding disk. And, for sure, the disk is moving faster at the chisel's outer edge then it is at the inner edge. (Aren't we going to have a beer together in CT this Summer? You're going to have to buy me an extra one!)

Re: Question

Steve D, in CT

There was a claim that one side of the blade would grind faster than the other because of the speed difference. Your photo proves that that is an unfounded concern.

I guess I'll have to make this up to you somehow.

Re: Question

Eliot

How does the photo show that?

Re: Question

Steve D, in CT

The blade is clamped to the guide and the guide is resting on two points forming a pivot. There is no freedom for the blade to twist because the pivot points prevent that.

Re: Question

Eliot

I believe I‘lll have to buy you the extra beer!