Results 1 to 15 of 15
  1. #1
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default tear-out frustrations....

    Hi everyone,

    finally had a go at turning a WA she-oak blank....the end grain sections are tearing out no matter what i do......

    I've tried sharpening the gouge and presenting it with the flute side on (or 3 oclock) - what i understand to generally be the correct entry positioning for cutting the inside of the bowl starting at the rim..

    and I've tried to shear-scrape with a rounded scraping tilted to a shearscraping angle....

    Blank is bone dry.

    I figure that some woods are more prone to this issue than others....but I've had some issues with this on my bowls over the last few months and figure technique must be a factor....

    any advice greatly approeciated.

    I reckon i have scope for a few more attempts before it gets way too thin.....

    argghhh!!

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #2
    Join Date
    Sep 2009
    Location
    armidale.nsw.australia
    Age
    70
    Posts
    2,005

    Default

    Hi faulko, have you tried a swept back grind on your gouge , present the tool almost upright
    Handle down low and very light cuts , you may have to lower your toolrest so you are on centre
    Line , Hope this helps .........or just get some 20grit sandpaper
    Cheers smiife

  4. #3
    Join Date
    Nov 2008
    Location
    Canterbury UK
    Age
    67
    Posts
    3,994

    Default

    Other than sharp tools and presentation to the wood. Whenever I have tear-out problems especially with punky type woods and those that are too dry I find that either a mist spray with water on the surface helps to swell the fibres so that they support each other better allowing for a clean cut. By using water it still leaves you open to apply the finish of choice.
    If the finish is one that is compatible with a sander sealer then a coat of that can also be used.
    With both methods, you may need to reapply as you cut down. With water, it dries out and sander sealer it only penetrates so deep.

    I do send to turn some quite punky wood at times especially spalted wood which have only just gone a little far.

    Trying to sand out the torn grain can be a right pain as it may take some time to get below it as well as having to resort to coarse grits which you then have to work through more grits to get rid of scratches from the very coarse grits

  5. #4
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    I wipe down with a wet cloth then either shear scrape or negative rake scrape. Light cuts and re-wet frequently. Cut down to dry wood and it will start tearing again.
    When it comes to shear scraping I subscribe to Robo Hippy's technique. Start the scraper by rubbing the bevel and tilt it into the wood until it just starts to cut. That gives a slicing cut.
    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  6. #5
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    Thanks all.

    ..i have another good sized blank of the same stuff so I assume it'll be the same...will give these suggestions a go...although i dont have a negative rake scraper.....

  7. #6
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    thanks - i thinki understand....does this method have the scraper tilted at an angle too?? I might see if Robo Hippy has this on youtube...

    - - - Updated - - -

    thanks - i thinki understand....does this method have the scraper tilted at an angle too?? I might see if Robo Hippy has this on youtube...

    Quote Originally Posted by tony_A View Post
    I wipe down with a wet cloth then either shear scrape or negative rake scrape. Light cuts and re-wet frequently. Cut down to dry wood and it will start tearing again.
    When it comes to shear scraping I subscribe to Robo Hippy's technique. Start the scraper by rubbing the bevel and tilt it into the wood until it just starts to cut. That gives a slicing cut.
    - - - Updated - - -

    yep. i hav had a gutful of sandy..this has been my exact expeirnce.

    def gonna try the water option next time

    thanks


    Quote Originally Posted by Dalboy View Post
    Other than sharp tools and presentation to the wood. Whenever I have tear-out problems especially with punky type woods and those that are too dry I find that either a mist spray with water on the surface helps to swell the fibres so that they support each other better allowing for a clean cut. By using water it still leaves you open to apply the finish of choice.
    If the finish is one that is compatible with a sander sealer then a coat of that can also be used.
    With both methods, you may need to reapply as you cut down. With water, it dries out and sander sealer it only penetrates so deep.

    I do send to turn some quite punky wood at times especially spalted wood which have only just gone a little far.

    Trying to sand out the torn grain can be a right pain as it may take some time to get below it as well as having to resort to coarse grits which you then have to work through more grits to get rid of scratches from the very coarse grits

  8. #7
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    Thanks Smife.....i susoect i dont understand what u mean properly....almost upright presentation sounds a bit scary..i wouldve thought it would easily catch on the wing - hence me thinking i dont understand...

    cheers


    Quote Originally Posted by smiife View Post
    Hi faulko, have you tried a swept back grind on your gouge , present the tool almost upright
    Handle down low and very light cuts , you may have to lower your toolrest so you are on centre
    Line , Hope this helps .........or just get some 20grit sandpaper

  9. #8
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  10. #9
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    Quote Originally Posted by Faulko View Post

    ....although i dont have a negative rake scraper.....
    On a convex surface (outside of a bowl) a skew chisel works as a NRS. That will at least let you try it. I have a slight preference for NRS over shear, I get a smoother finish off the NRS compared to shear although practice will likely fix that.

    What ever way you go, NRS or shear, they need to be sharp and re-sharpened frequently. Try to push on for a little too long before re-sharpening and it will start tearing.
    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  11. #10
    Join Date
    Sep 2009
    Location
    armidale.nsw.australia
    Age
    70
    Posts
    2,005

    Default

    Quote Originally Posted by Faulko View Post
    Thanks Smife.....i susoect i dont understand what u mean properly....almost upright presentation sounds a bit scary..i wouldve thought it would easily catch on the wing - hence me thinking i dont understand...

    cheers
    No it,s not scary , I mean pointing the gouge tip at half way between 1and 2 o,clock , and just use the
    Left side of the wing very lightly start in the centre and work your way to the outside
    Cheers smiife

  12. #11
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    thanks - i use a skew like negative rake on outside of bowls regularly..but never have on inside....dont have one rounded enough to do that.........i assume u use negative rakes on inside of bowls too??

    Quote Originally Posted by tony_A View Post
    On a convex surface (outside of a bowl) a skew chisel works as a NRS. That will at least let you try it. I have a slight preference for NRS over shear, I get a smoother finish off the NRS compared to shear although practice will likely fix that.

    What ever way you go, NRS or shear, they need to be sharp and re-sharpened frequently. Try to push on for a little too long before re-sharpening and it will start tearing.

  13. #12
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    so start at the bottom or half way along the inside wall and then work my wat back to the rim??

    Quote Originally Posted by smiife View Post
    No it,s not scary , I mean pointing the gouge tip at half way between 1and 2 o,clock , and just use the
    Left side of the wing very lightly start in the centre and work your way to the outside

  14. #13
    Join Date
    Sep 2010
    Location
    Port Sorell, Tasmania
    Posts
    592

    Default

    Quote Originally Posted by Faulko View Post
    i assume u use negative rakes on inside of bowls too??
    Yes and i have 2 that I use inside bowls, a larger woodcut NRS with more gentle curves and one I ground from a 12mm skew with a tighter radius.
    You can't use up creativity. The more you use, the more you have. ~Oscar Wilde

  15. #14
    Join Date
    Sep 2008
    Location
    North Carolina, USA
    Posts
    2,327

    Default

    A regular scraper pointed down is a negative rake scraper. I sharpen my scrapers upside down at about an 80 degree angle, which raises a slight burr. I take a VERY light cut pointing down. The burr lasts about 15 seconds. My grinder is at the right end of the lathe and a flat rest is at the left wheel. I take a cut, put the scraper on the rest, hold down with a finger give a sweep of the curved scraper against the wheel, make a cut.

    A slightly swept back grind on a bowl gouge also works. I sharpen using a jig, then using a piece of rolled up 320 or 400 grit paper hone the inside. I present the gouge to the middle of the bottom of the bowl, top of gouge facing facing 9 o'clock, and sweep up to the rim.

    Having the bowl rotating as fast as you are comfortable with helps. Resharpening and honing frequently helps. All of the above advice is good. We all have to figure out our own best practice and keep doing it. For me, it takes about 20 hours in short sessions in front of the lathe to get good at a technique.
    So much timber, so little time.

    Paul

  16. #15
    Join Date
    Jul 2013
    Location
    newcastle
    Posts
    157

    Default

    Thanks to everyone for the advice. This is a great community.

Similar Threads

  1. Ryobi ETS-1526 Table saw frustrations.
    By Kiwi75 in forum TABLE SAWS & COMBINATIONS
    Replies: 7
    Last Post: 5th June 2013, 11:03 PM
  2. Some frustrations
    By artme in forum TIMBER
    Replies: 6
    Last Post: 16th February 2012, 09:19 PM
  3. BOB Frustrations
    By chrisb691 in forum CNC Machines
    Replies: 3
    Last Post: 24th November 2008, 09:02 PM
  4. On-line frustrations .........
    By masoth in forum Links to: TIMBER & HARDWARE SUPPPLIERS
    Replies: 6
    Last Post: 27th September 2006, 11:11 PM
  5. Air Conditioner - DIY Reset and Maintenance - repair services frustrations
    By barrysumpter in forum PLUMBING, ELECTRICAL, HEATING, COOLING, etc
    Replies: 31
    Last Post: 19th August 2006, 10:18 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •