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George Conklin
01-15-2009, 2:24 PM
I recently watched a video where the turner was demonstrating using a scraper for putting a fine finish on the inside of a bowl.
My experience with scrapers makes more 'tear out' than a clean finish.
Do you think this is due to a dull tool or tool alignment/placement issue. I am also just dusting the surface, not taking large, deep cuts.
Thanks for the help.

Reed Gray
01-15-2009, 2:38 PM
George,
With a scraping cut (the scraper held flat) you will get more tear out, but with it held at a 45 degree 'shear' angle, you can get a fine finish cut. The scraping cut is excellent for roughing. See my responce to 'Am I cheating'
robo hippy

Jeff Nicol
01-15-2009, 2:42 PM
George, Each type of wood is different and depending on the grain, knots, figure, orientation of wood etc. can all affect the outcome of the scraper. But like everyone says the burr is what does the cutting. If the bevel on the scraper is to high or to low of center that will cause some problems. The best wat that I have found to make them work is to put the tool rest so the burr is a little above center. Make sure that the space between the wood and the rest is as small as you can get it. Present the scraper at a small downward angle and move slowly into the wood. It you just push straight into the wood this is where a tear will probably occur, as the scaper is tipped down at the initial cut causing it to cut deeper than you want. The only time I keep the wide part of the scaper flat on the rest is when I want to take heavier cuts and remove more wood. Then when I am ready to make the finish cut I turn the scaper on it's side and shear scrape the final few passes. The finishing cutts should be very light and as many as it takes to clean up any tool marks. So patience is important, you can't rush perfection!

It is hard to talk about it and much easier to watch someone do it. If there is a turners clup near by see if a member can give you some pointers. There are lots of videos out that show how its done, Jimmy Clewes used them in some of his.

Keep practicing! Hard woods are easier than soft woods to scrape.

Hope It all makes sense.

Jeff

Steve Schlumpf
01-15-2009, 2:53 PM
George - make sure you have a sharp tool and make sure that the cutting edge is very close to the centerline with the tool handle slightly raised. Jeff gave a good explanation of tool rest placement. Other than that - make sure you keep the scraper moving in a continuous sweep (left to right) towards the center of the bottom of the bowl. If you move the scraper from the center towards the rim (which works great for roughing out) you will get tearout.

Bernie Weishapl
01-15-2009, 3:05 PM
I agree with Reed and Jeff. If you turn your scraper to about a 45 deg angle on your tool rest and take light cuts it will leave a really nice finish.

Don Carter
01-15-2009, 4:56 PM
George;
You have received some great advice here. I was having problems with scrapers until I got a big heavy scraper and learned the shear cut. I think the heft of a scraper really does help in getting a smooth finish inside a bowl.

All the best.

Don