Tear out and shear scraping

[sasjzl]

Hi all,

Just wanted to get some thoughts from the group on how they may be using shear scraping, as I have seen Lyle Jamieson, Bill Grumbine and David Ellsworth demonstrate on their excellent videos to deal with tear out. I am discovering that different would offer different levels of tear out but I am not able to use shear scraping, with an Ellsworth grind, to get rid of tear out. All three of those expert turners clearly recommend it. I am having no problem with push and pull cuts and riding (or floating) the bevel but I am just getting very frustrated with not being able to deal with tear out using this technique they all seem to agree on.

I would love to hear from anyone who has tackled the tear out problem with a cutting technique. And I mean just minimizing it after rougher cuts, not eliminating it.

Thanks very much,
Jim Lee

 

[NCTurner]

SHARP tools.

 

[sasjzl]

I guess I have to learn how to sharpen sharper. I use an Ellsworth grind with a standard issue Oneway side grinder. A new grinder with new grinding wheels of 120 aluminum oxide wheels. When I sharpen them the gouge feels very sharp. I am able to get what appear to me to be very, very fine shavings when I do shear scrape. I just cannot get rid of, or minimize, tear out. If I was a betting guy I would be that there is something I am missing in my sharpening routine but I am stumped right now as to what it is. I am imitating Lyle, Bill and David as best as I possibly can. All three are using a similiar gouge and side grinder.

I am going to be doing a weekend workshop with Bill Wallace in a couple of weeks and hope to get to the bottom of this tear out lesson before I tear what is left of the hair on my head.

Thanks,
Jim Lee

 

[woodArtz]

Takes a bit of practice, but it is an effective technique. As Gary mentioned, you must have very sharp tools to start with. I find that the Ellsworth grind isn't as effective as the Irish grind. The Ellsworth generally has a rounded edge near the tip of the gouge and thus requires more finesse. With the Irish grind, the turner can easily lay the wing of the gouge against the surface at a high angle and pull it along. The result should be some fine curls and reduced tear out. You might play with the presentation of the gouge to the surface a bit. Basically, you can go from a fully closed gouge face to a significantly open presentation that is more aggressive. The more aggressive, the deeper the cut and removal of the tear out. Whew... sorry to be so long winded. Hope that helps.

 

[NCTurner]

I am going to be doing a weekend workshop with Bill Wallace in a couple of weeks and hope to get to the bottom of this tear out lesson before I tear what is left of the hair on my head.

Definitely do that well worth the price of admission.

 

[Rob]

I have also put a burr on my large skew and used this as a sharp scraper to clean out tear out. This too takes some practice.

 

[sasjzl]

Rob, When you say 'put on a burr' do you mean the burr that naturally forms from sharpening or is there some method seperate from sharpening that you do?

Thanks,
Jim Lee

 

[boxxmaker]

Have you thought about honing you tools?I never gave it much thought as I thought my tools were sharp enough,untill a friend of mine in Cullowee NC showed me the difference in a sharp tool and a honed tool.HUGE.As for the scraper,they to have a tool just for putting a burr on them.Never used them,but hear they work quite well.

 

[SteveColes]

Rob, When you say 'put on a burr' do you mean the burr that naturally forms from sharpening or is there some method seperate from sharpening that you do?

Thanks,
Jim Lee

I don't know how Rob does it, but I started doing it with burnishing rod just like a card scraper, but then I found this. It is quick and easy to use. I just mounted it next to my grinder:thumbs_up

 

[boxxmaker]

Thank you kind sir,new somebody would come up with it :icon_cheers

 

[Trent Mason]

Definitely sharp tools. I don't have a lot of the special stuff at my disposal, so have to rely on technique. When roughing out, go for it, but once you get close to the shape you're looking for, slow down and start the very light cuts. I watched Bill Grumbine's dvd and I pretty much duplicate his sheer cut. I think it mainly comes down to how sharp your gouge is. Do you have a sharpening jig for it? I made my own and it works.

 

[NCTurner]

http://woodturning.maine-web.com/shapeshifter/scaper.html

http://www.woodturningvideosplus.com/torn-grain.html

http://azwoodturners.org/Sharpening2.pdf

 

[Rob]

Rob, When you say 'put on a burr' do you mean the burr that naturally forms from sharpening or is there some method seperate from sharpening that you do?

Thanks,
Jim Lee

Just what's left from sharpening on the grinder, you can feel it if you sharpen one side a little more. A little trick I learned from the turning instructor at John C Campbell. Sheer scraping with a skew, holding it at a 45 degree angle to the outside of the bowl.