Getting a sharp edge........

[Odie]

Odie, This might be interesting. Dunno how much it costs. Google brentbeach/sharpen and go to his sharpening pages.

That's some great information, Texian........and the video is a good point to ponder, as well......

Here's a direct link:

http://www3.telus.net/BrentBeach/Sharpen/index.html

Now, this fellow gets about the sharpest edge that is humanly possible on his bench plane blades.

Wow, is all I can say! 😀





OK, OK.....we lathe turners need a reality check here! 🙂

It should be obvious to all of us that our lathe tools don't just suddenly get dull. They begin dulling the very moment you begin using them......and, if we compare hand plane blade edges to lathe tool edges, there is one blaring point of difference. The lathe tool edge is subjected to a hundred times more cutting duration and abuse than a hand plane ever will.

The question for me is this: Is it worth the effort to sharpen our lathe tool edges to that fine a degree of sharpness? We must realize that when we begin using the tool after sharpening, dulling is virtually instantaneous, and ongoing. We also MUST realize there is some point at which sharpness just isn't applicable to the lathe.....it will be wasted almost immediately.

How sharp do we need to get it? Boy......now, I wish I had the answer that none of you lathe turners could dispute, but there has got to be somewhere in the spectrum of sharpness that the degree of sharpness just isn't going to translate in any advantage at the lathe. Can we all agree on that point, or not?

Most of you are aware of my little inquiry about magnifying the cutting edge to get a better perspective of how sharp they are. I've ordered the 45x illuminated loupe. Even though I think I'm pretty darn good at getting a sharp edge, I suspect I might be able to improve my techniques.......I don't know that, but I'd like to find out! :cool2: If I can improve the sharpness, is it going to be to a degree that is useful in lathe turning????? That's an unanswered question in my mind.:mad:

Even yet......there's still more to the story! Let's just say that I can sharpen to a point that will no longer be of any realistic significance if I can possibly get it any sharper.....because the resulting fineness of cut won't reflect any advantage to it......or won't last to any useful length of time. If I were to hit that "sweet spot" in sharpness, there is always the spinning wood, and how it will react to any tool, no matter how sharp/dull it is. I specialize in thin wall bowls, and I've always had a constant battle with resonating wood......that's because when it's thin, it's flexible.

Resonating wood is toned down quite a bit from the Oneway bowl steady......but, can that be improved upon????? As with sharpening, I just don't have all the answers.....but, this Christmas I've decided to give myself a new bowl steady rest. It will be expensive, but should be more stablizing than the Oneway......dunno for sure. I will have the options of experimenting with 3, 4, and 5 wheels at various locations.......but, that will be a whole 'nuther chapter in my quest for.....


......."the perfect bowl".......



(Does this, in any way, remind you of that surfer searching for the perfect wave? I believe the movie was called, "Endless Summer"! )



Ha! Ha! Ha!


Merry Christmas yoo all!

ooc

 

[hockenbery]

For most bowl and hollow form work the edge off a 60 grit wheel is great.
I know at least 5 excellent turners who own a Tormek, one of the finer sharpening systems. Non use it for their gouges simply because the sharper edge doesn't pay off. You won't get a lot of agreement when it comes to sharpening.

One of the big contributors to "resonating wood" is bevel drag. This is from friction where the bevel touches the wood behind the cut.
Severe bevel drag causes the tool to bounce so much it won't cut.

Bevel drag increases with pressure on the bevel, gunk on the bevel and total bevel contact.

Turners that over do the "ride the bevel" press the tool too hard against the wood. Lighten the touch. The bevel should float over the cut surface.

Resins build up on the bevel from some woods especially wet wood. this makes a sticky surface that grabs the wood sort of like a brake applied to spinning wood. Sharpening cleans the bevel. I often sharpen tools more to clean the bevel than to restore the edge. I also do a lot of early roughing not riding the bevel.

A long bevel usually has more bevel contact than a short one. I often use a 1/4 gouge to clean up a surface. much shorter bevel than the 1/2 gouge.
A micro bevel grind reduces bevel drag. Johannes Michelson grind is the micro bevel to extremes. It is a great grind for minimizing bevel drag. Maybe that is why Johannes is the master of turning thin.

Happy turning,
AL

 

[Richard Baker]

Thought you would get a charge out of that Odie. Some very impressive and careful, detailed work by Brent.

 

[Odie]

Thought you would get a charge out of that Odie. Some very impressive and careful, detailed work by Brent.

Yep, thanks for the link, Texian.......about made my jaw drop to see and get a mental perception of just how sharp is possible. I've not heard much discussion between lathe turners in terms of "microns".....but, if it ever does reach that point of discussion, I'd tend to think we're splitting hairs that might make a difference on paper, but not on the lathe!

All I want for Christmas is what money can't buy.....knowledge as a derivative originating from experienced experience! 😀:cool2:

ooc

 

[Odie]

For most bowl and hollow form work the edge off a 60 grit wheel is great.
I know at least 5 excellent turners who own a Tormek, one of the finer sharpening systems. Non use it for their gouges simply because the sharper edge doesn't pay off. You won't get a lot of agreement when it comes to sharpening.

One of the big contributors to "resonating wood" is bevel drag. This is from friction where the bevel touches the wood behind the cut.
Severe bevel drag causes the tool to bounce so much it won't cut.

Bevel drag increases with pressure on the bevel, gunk on the bevel and total bevel contact.

Turners that over do the "ride the bevel" press the tool too hard against the wood. Lighten the touch. The bevel should float over the cut surface.

Resins build up on the bevel from some woods especially wet wood. this makes a sticky surface that grabs the wood sort of like a brake applied to spinning wood. Sharpening cleans the bevel. I often sharpen tools more to clean the bevel than to restore the edge. I also do a lot of early roughing not riding the bevel.

A long bevel usually has more bevel contact than a short one. I often use a 1/4 gouge to clean up a surface. much shorter bevel than the 1/2 gouge.
A micro bevel grind reduces bevel drag. Johannes Michelson grind is the micro bevel to extremes. It is a great grind for minimizing bevel drag. Maybe that is why Johannes is the master of turning thin.

Happy turning,
AL

Good point about the bevel, Al.

All who are interested in the "resonating" subject would be wise to understand the relationship of the bevel contact, and the propensity for it to initiate resonating without expert tool control.......however, I must point out that the bevel is not the only source of resonating wood. Lathe speed is an important one, too. You can slow down the lathe to the point where resonating won't occur, but the consideration there is that one element of finer cutting is the result of greater lathe speeds, not slower. Another consideration is the wood itself, species and even differences between one example, and another of the same species.......and of course, the configuration, or profile shape you attempt to produce on that wood.

The bevel, as important a consideration that it is, is only a piece of the puzzle!......and, all of those puzzle pieces are in a constant state of change as you remove wood, not to mention the puzzle pieces connect differently from bowl to bowl! Grrrr!

(((((Grrrr! I think I borrowed that expression from you, Gretch! Hope that's ok with you! 😀 )))))

You are very correct that, not only do turners seem not to agree on much about sharpening, they don't seem to agree on much of ANYTHING connected to operating a lathe! Ha!.....what you get is consensus among certain segments of the woodturning fraternity, but NEVER, it seems, is there any universal agreement on anything, but the most novice of subjects. I'm one who thinks that 60gt isn't good enough! Heck, I don't think 80gt is good enough for gouges......I do think it's good enough for scrapers, but, for gouges, I use 80gt for a basic grind, then folowed up with 200gt wet wheel, then touched up inside the flute with slipstone or diamond hone....my wet wheel is an older but similar machine to the Tormek. (I do believe the Tormek uses a 250gt wheel, and I'm using a 200gt, though.)



Merry Christmas!

ooc

 

[David Somers]

Yep, thanks for the link, Texian.......about made my jaw drop to see and get a mental perception of just how sharp is possible. I've not heard much discussion between lathe turners in terms of "microns".....but, if it ever does reach that point of discussion, I'd tend to think we're splitting hairs that might make a difference on paper, but not on the lathe!

All I want for Christmas is what money can't buy.....knowledge as a derivative originating from experienced experience! 😀:cool2:

ooc

Odie, Just curious, which steady rest did you finally decide on.

Personally, I freeze my bowls in water in a liquid nitrogen bath and then use a laboratory microtome to get extra extra thin cuts. That lets me start sanding with as high as 80 or 100 grit! <big grin>

Christmas Morning at 4,000 feet in Volcano HI on the Big Island! 29 degrees and starting to warm up for an expected high in the low 70's! Mauna Loa and Mauna Kea summits are visible with some snow on the summit of Mauna Kea! Clear skies....no volcanic fog! Looks like a gorgeous stunning day! Hope everyone is enjoying an equally stunning day...no matter what your local weather may be!! Merry Christmas gang!!

Dave

 

[Odie]

Odie, Just curious, which steady rest did you finally decide on.

Personally, I freeze my bowls in water in a liquid nitrogen bath and then use a laboratory microtome to get extra extra thin cuts. That lets me start sanding with as high as 80 or 100 grit! <big grin>

Christmas Morning at 4,000 feet in Volcano HI on the Big Island! 29 degrees and starting to warm up for an expected high in the low 70's! Mauna Loa and Mauna Kea summits are visible with some snow on the summit of Mauna Kea! Clear skies....no volcanic fog! Looks like a gorgeous stunning day! Hope everyone is enjoying an equally stunning day...no matter what your local weather may be!! Merry Christmas gang!!

Dave

Hello again, Dave.........

Do you really use liquid nitrogen?

I went with "The Spin Doctor".

click:

http://www.theokspindoctor.com/index.html

The Spin Doctor isn't the cheapest bowl steady, but I was impressed with the man who makes them, his design, rigidity of his bowl steady, and the materials he uses. Keith Clark is his name. He probably considers me as some kind of nut, or maniac, because I kept changing my mind about how I wanted it made, and positioning of the wheel arms! He was truly great to work with, and is making up a completely unique bowl steady from my specifications.

Check went out in the mail a couple days ago, and I ought to be using the Spin Doctor very soon!

I was working on a bowl this past week that is just an absolutely outstanding piece of wood, black line spalted Maple that still had plenty of structural integrity.......probably among the top few most beautiful pieces of wood I've ever had the pleasure of turning. It warped badly during seasoning, and I'll have to go thinner than I had planned. I've decided to put this bowl on hold, and will use the Spin Doctor to complete it. If I end up losing this one, I'll be one very very unhappy camper! :mad:

ooc

 

[john lucas]

Odie Al must be standing at my lathe, or maybe I stood at his. We teach the same thing. I call it gliding the bevel rather than ride the bevel. I think there are several other things that work as well. Short bevel was mentioned.
Sharpener cutting angle requires less pressure to cut so you naturally push on the bevel less. Sharper tool. This is a case where the 60 grit grind might not be the best, when you need a very sharp tool for a final cut to keep the vibration down. Again a sharper tool means that you can hold the tool more gently which translates into less pressure on the bevel.

 

[Odie]

Odie Al must be standing at my lathe, or maybe I stood at his. We teach the same thing. I call it gliding the bevel rather than ride the bevel. I think there are several other things that work as well. Short bevel was mentioned.
Sharpener cutting angle requires less pressure to cut so you naturally push on the bevel less. Sharper tool. This is a case where the 60 grit grind might not be the best, when you need a very sharp tool for a final cut to keep the vibration down. Again a sharper tool means that you can hold the tool more gently which translates into less pressure on the bevel.

Yep.....I think so, John!

I didn't disagree with AL on the importance of correct bevel usage, and I can't with you either!

ooc