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Lathe Chisel Sharpening ANGLES and/or BEVELS PER TOOL

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Forum topic by HorizontalMike posted 01-14-2013 07:34 PM 6277 views 2 times favorited 31 replies Add to Favorites Watch
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HorizontalMike

6968 posts in 1665 days


01-14-2013 07:34 PM

Topic tags/keywords: lathe turning chisels sharpening angle bevel

I found this old “Blog” while searching for info on proper sharpening angles/bevels for the different turning tools.
http://lumberjocks.com/auggy53/blog/21516#comment-1457666

I am wondering if some folks would mind chiming in on each of the turning tools and the best/proper grind for each, by name. I am new at this and am going through my first-ever sharpening sessions with my belt sharpener system. I also know that a few other LJs have also recently gotten into turning, so “we” could use some good ol’ LJs advice. Thanks in advance…

-- HorizontalMike -- "Woodpeckers understand..."


31 replies so far

View MonteCristo's profile

MonteCristo

2098 posts in 939 days


#1 posted 01-14-2013 07:51 PM

Mike:

Check out Leonard Lee (of Lee Valley fame)’s book on sharpening. It’s a no nonsense guide to sharpening all kinds of ww tools, including lathe tools. He debunks a number of myths that are out there as well. It’s a Taunton Press book, “The Complete Guide To Sharpening” is the title (I think).

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

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HorizontalMike

6968 posts in 1665 days


#2 posted 01-14-2013 08:59 PM

I’ll look for it. Plus I need to dig into a couple of old crates of mags & books I was given some time ago to see if anything turns up there. Thanks.

-- HorizontalMike -- "Woodpeckers understand..."

View David Kirtley's profile

David Kirtley

1285 posts in 1748 days


#3 posted 01-14-2013 09:16 PM

The angles are in the same range as regular wood chisels and planes. Higher angle for figured woods. Very steep for scraping.

The gouges will have what is referred to as a fingernail grind. The main idea is to have the bevel radially ground so it will be good for coming in at different angles and for doing a cut while rotating the tool. The gouge is a bit special in that it is a “self-jigging tool”. You can ride the bevel to act like a depth stop for the cutting. 30 deg or so is a good start for softer wood (and green wood) and 40 deg for more hard woods. These are a fairly recent invention. Previously this work was done with hook tools and ring tools (not for cutting rings—the cutting edge is a sharpened cylinder that is a bit tricky to sharpen)

The scrapers are all pretty easy. Almost 90 deg and you are good. The less than 90 deg part is to give clearance behind the cutting edge. Really should only be used for trimming and handling nasty grain.

Parting tools generally have a lot of clearance (bottom and sides) and are either done like a really thick but narrow scraper or are kind of a weird bevel on the top and bottom. Diamond shape in profile. This is to reduce friction while cutting. They generally have a pretty beefy cutting edge because you ride them pretty hard. One of the harder tools to get used to. The angles are usually about 60 degrees and up for the cutting edge The diamond shaped ones are usually sharpened the same from each direction so you can use them either side up.

The skew…. This one is different. It gets 2 bevels like a knife. Sharpened at the same angles as a knife. 20 deg or so from each side. Many people are afraid of skews. They can bite. The thing is, this is your surgeon’s scalpel. It can be dainty for working on delicate features. It can also remove material at a frightening speed. It’s main purpose is slicing.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

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johnintecumseh

113 posts in 2168 days


#4 posted 01-14-2013 09:23 PM

Hey Mike , look up Oneway.ca and thompsonlathetools.com 2 good sites for bowl gouge sharpening. keep smiling John

-- retired and smiling

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rum

148 posts in 1336 days


#5 posted 01-14-2013 09:47 PM

Actually I’d take Davids statement about them being the same angle as regular chisels, etc.. a step further.

I found (and continue to find) it really useful to try my lathe tools out at the bench and/or with the lathe turned off for a few test cuts. Doing that taught me more about how the tool should approach the wood and what angle was good for grinding, etc.. than any of a dozen videos. Basically try taking shavings off of a piece of wood with whatever tool your using. When you can get nice clean shavings from a 2×4 on the bench then transfer that to a piece with the lathe off you’ll have a pretty good idea of where the tool should be in relation to the work for a given grind/part/whatever.

Now I’m not talking down the sharpening videos, both the oneway and thompson ones John pointed out were very useful as well, I’d also add the D-way videos to that list: http://www.youtube.com/channel/UC8jsr2OBog-RwMjbNvYJ8Lg?feature=watch
the last couple there especially are applicable to any grinding wheel, my bowl gouges got a whole lot better after watching that.

I would disagree that scrapers should only be used for trimming/nasty grain (granted they do excel there), check out these two videos from Reed Grey (aka Robo Hippy) and I think you’ll change your mind at least a little :D: Turning with scrapers: http://www.youtube.com/watch?v=hKdqiAc0jx4 Sharpening scrapers: http://www.youtube.com/watch?v=UQ7w6yFhw4c
They can be really flexible and useful tools. They are especially useful (imho) for getting into complicated angles and are somewhat more forgiving than a gouge for a lot of operation (especially when used with a bit of a negative – downward facing) angle).

The skew is indeed subtle but well worth the time, there are dozens of ways to adjust the details on how its sharpened so take some time on a cheap skew to try a few and see what works for you. Its worth spending a fair bit of time with any one grind before switching so you have gotten over the “its all new” part and settled down to use the tool.

View David Kirtley's profile

David Kirtley

1285 posts in 1748 days


#6 posted 01-14-2013 10:28 PM

Rum,

He is cutting and not scraping :) Look carefully at how high he is from the center of rotation and how his tool is slicing at an angle. He is just using skew technique with a single beveled tool with rounded corners and calling it a scraper. Nothing wrong with that at all. Skews are awesome. The chips flying speak for themselves. If you are not covered in them, you are doing it wrong. :) The problem beginners have is that they just sit there plunging the tool straight in generating nothing but dust doing nothing but using too much tool pressure and producing a lot of heat and chatter. Many times the piece will just blow up in their face.

Thankfully, I started turning with material that was barely able to support itself. I started with clay on a potter’s wheel. By the time I got to solid material, it was wild to actually be able to push the tool in without everything flying apart.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View HorizontalMike's profile

HorizontalMike

6968 posts in 1665 days


#7 posted 01-14-2013 10:39 PM

Wow, great videos! That sure simplifies things for me. So there are no hard and fast angles, but rather ranges of angle depending on hardness and task. Cool…

-- HorizontalMike -- "Woodpeckers understand..."

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HorizontalMike

6968 posts in 1665 days


#8 posted 01-14-2013 10:44 PM

David: ”...The problem beginners have is that they just sit there plunging the tool straight in generating nothing but dust doing nothing but using too much tool pressure and producing a lot of heat and chatter….”

That sounds almost like you watching me on my first turning! ;-) Except for the chatter, all I was really doing was making dust. I didn’t have a clue as to how that skew worked as was just trying figure it out on the run. Now I know better.

-- HorizontalMike -- "Woodpeckers understand..."

View David Kirtley's profile

David Kirtley

1285 posts in 1748 days


#9 posted 01-14-2013 11:02 PM

Mike, For a skew on a spindle, start with just the lower 1/3rd or so of the blade until you get used to it. Keep the point away from the work. The point will catch badly if you are not careful. You ride on the bevel and then shift a bit to start cutting. All of a sudden, the chips will just spray off the work. You shift your body to steer the tool just like riding a bike. Only move your hands and tool for really delicate cuts. Everything else will be whole body.

Get used to turning to dimension. Start out just roughing out and turning a cylinder. Turn tenons on the ends. Then make grooves on the piece. Then round off the pieces between the grooves. Then you turn hollow portions between the grooves. When you go to part off, it is just a deep groove that goes all the way to the center. That’s it. Beyond that it is just doing things to size until you try hollow forms like bowls and beyond. Don’t worry about those until you can do spindles.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View rum's profile

rum

148 posts in 1336 days


#10 posted 01-14-2013 11:46 PM

When Reed raises the angle of the tool for the finishing cuts he is definitely using it more like a skew; for the initial cuts I would still argue that its more of/mostly a scraping cut – imho demonstrating you can get awesome curlies from a scraper :D. You can obviously make scraping cuts with a skew as well but that’s not generally its normal domain.

I would also note one thing I figured out that helped me a lot with scrapers (at least getting started) is to not leave the grinding “burr” on it. The burr makes it cut (and thus grab) a lot more aggressively. That’s probably fine if you’re used to it but can suck it into the wood in a hurry if you’re not expecting it and can cause a “bad day”. I mostly just hone the top a few strokes on a stone after grinding and its all good. Cuts slower but a lot easier to control.

You are so very very correct on the dust versus shavings comment, regardless of the tool (even scrapers) you can get nice shavings when you’re touching it correctly and dust is a sure sign you’re doing it wrong.

Spot on the skew, I would also caution that touching the heal – while not dangerous like the point – is annoying because you keep getting these awesome backward spirals. It took me a while to figure out that, despite what the folks in the videos might say, you don’t really want touch either end of the skew to the wood1 in planing/carving mode but for cutting beads you are using the edge just barely back of the heal (the closer you get the better the cut until Ziiiippp a spiral :D).

[1] the obvious exception to this is when the skew is point down and you are making parting type cuts with it.

Here is a really good illustration of the “practice piece” for skew work: http://www.youtube.com/watch?v=vA91yJ9KhKU

View Druid's profile

Druid

695 posts in 1546 days


#11 posted 01-14-2013 11:47 PM

Hi again, For a bit more sharpening information, Lee Valley Tools has some free articles at . . .
http://www.leevalley.com/en/home/Articles.aspx?p=32
Dwight – You are correct about the title of the book on sharpening, and chapter 6 deals specifically with Chisels.

-- John, British Columbia, Canada

View David Kirtley's profile

David Kirtley

1285 posts in 1748 days


#12 posted 01-15-2013 12:19 AM

Pfft. This guy knows how to use a skew :)

!!

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View MonteCristo's profile

MonteCristo

2098 posts in 939 days


#13 posted 01-15-2013 01:26 AM

Watched David’s video (post #12) about a Moroccan dude turning a chess piece. Amazing what a guy can do with a little ingenuity !

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View HorizontalMike's profile

HorizontalMike

6968 posts in 1665 days


#14 posted 01-15-2013 01:35 AM

David,
Yeah, I had seen that one before, but I just watched it again because it is so amazing! Thanks.

John,
Thanks for adding more info. Digging around in those crates, so far I have found these paperbacks:

  • Woodturning in Pictures by Bruce Boulter 1983 Sterling Publishing Inc.
  • Turning Wood with Richard Raffan 1985 Tauton Press
  • Creative Woodturning by Dale L. Nish 1975 Brigham Young University Press

They look like relative beginners stuff, so this is good. Also looks like I have Woodturner Journal Mags from ~1985-1999. Most of these looks like advanced stuff that is beyond me for the time being. When I was given this stuff, 10-12 crates full, I really wasn’t quite sure what I really had. Now to find the time to read, as long as it does not cut into shop time ;-).

-- HorizontalMike -- "Woodpeckers understand..."

View rum's profile

rum

148 posts in 1336 days


#15 posted 01-15-2013 01:58 AM

The reading time overlaps well with beer time (actually turning does not). I love that video to although I always feel bad about my (lack of) skills everytime I see it :|

BTW: one other thing I should add is if you don’t have a good face shield please do get one. The Uvex Bionics is pretty reasonably priced and works well. The woodturning community has had several very experienced members pass on in the last year because a piece of wood let go and clocked them in the face. Its well worth the $35.

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