Sharpening scrapers

[Joe Hillmann]

I have another question on chisels for the lathe.

How do you sharpen a scrapper for use on a lathe. Do you sharpen it like you would a cutting edge where you face the backside to remove the burr or do you sharpen it more like a cabinet scraper and the burr is what does the cutting? If the burr is what does the cutting can anyone direct me towards a picture heavy tutorial on how to sharpen them?

I made a scraper last night and sharpened it like a regular chisel or plane blade and it kind of cut but left a very rough finish.

[Brian Brown]

The burr does the cutting. I have no tutorial, bit there is a scraper burnisher available to help, and it comes with instructions. dubdubdub.woodturnerscatalog.com/store/Sharpening___Honing___Scraper_Burnisher___scraper_ burnisher?Args=

[Al Rogers]

I sharpen my scrapers by placing them face (top) down on the grinders tool rest and make a light pass. Ensure there are no flat spots at the cutting edge.
I hold the tool slightly down - at about an 8 o'clock position to the wood, with the cutting edge on the works center line.

Mind you that I only use my scrapers for light finish cuts

Alliance

[Jim Burr]

To add a bit...the top of the scraper, where the burr is, does all the cutting. Since it is a rather small cutting area, it needs to be refreshed often. Keep in mind the correct angle of use for a scraper handle up! I can't think of one "expert" that deviates from that rule as this has been hashed and re-hashed at least a dozen times in the last year.

[Wally Dickerman]

Lots of answers on sharpening scrapers. I grind my scrapers using a 60 deg. nose angle. Use a coarse wheel to raise a burr. In normal use, the handle should be slightly up. On the outside of a bowl, scrape a bit below center and on the inside, on a bit above center. Fewer serious catches that way. Most turners use the scraper with a very light touch and going with the grain. Heavy handed scraping will produce a torn, rough surface.

Do NOT use a card scraper inside a bowl. There have been some serious accidents resulting from losing control of the scraper.

[Russell Neyman]

I guess my comment when it comes to a scraping cut is that despite the size of the tool, the trick is always to cut with a very small portion of the edge. Sometimes this is in the center of the tool, and sometimes the sharp corner. Like the others, to make any pass that will remotely be a finish I make an extremely light cut. It's the bullnose scraper for the inside of a bowl that has the most value, because it allows me to make gradual, rounded transitions from the bowl's bottom to the sides.

It's pretty common to take old tools and create specialized scrapers for a variety of uses. I have one narrow grind I use to clean out the bottom of a flat channel, as well as a couple ground like a small cove.

(Wally, I sent you a personal email message. Please check your inbox.)

[David E Keller]

I flip them upside down on a platform and grind them so as to drag a burr up. Just set the platform to the desired angle and let 'er rip.

[Andrew Kertesz]

The angle between the scraper and the wood should always be less than 90 degrees.

[Nathan Hawkes]

I have another question on chisels for the lathe.

How do you sharpen a scrapper for use on a lathe. Do you sharpen it like you would a cutting edge where you face the backside to remove the burr or do you sharpen it more like a cabinet scraper and the burr is what does the cutting? If the burr is what does the cutting can anyone direct me towards a picture heavy tutorial on how to sharpen them?

I made a scraper last night and sharpened it like a regular chisel or plane blade and it kind of cut but left a very rough finish.




Joe, there is no "wrong" answer to your question, but which one is right for you depends on what you are trying to cut. I frequently remove the burr on my scrapers, but it really depends on what you are trying to use them for. If you are doing endgrain turning, like making lidded boxes, take the burr off--I get a much cleaner cut that way. But if you are doing green bowl turning, the answers about raising a burr can all help you. There was an article in American Woodturner a while back that talked about scraper sharpness, and had extreme closeup pictures (200x magnification) of the cut surfaces, using many different methods of cutting, with and without burrs, and with ragged off-the-grinder burrs, or ones raised with a burnisher. Spoiler alert; I use a diamond hone and or motorized waterstone with my scrapers now, and get great results.

Important side-note; when you talk about a ragged surface, I have to ask what way you are presenting the tool, was it wet or dry wood, and on the rim or in the bottom, or outside of a bowl surface?

[Reed Gray]

There are a number of ways to sharpen scrapers, and probably about the same number of ways to sharpen gouges.

First, I prefer a more blunt bevel angle. I think mine are around 70 to 75 degrees, which means more blunt and not pointy like bench chisels. I sharpen on a platform which is set to the proper bevel angle. I have them sitting face up which leaves a nice grinder burr. I don't know about having them with the cutting/burr edge down like David does, but the burr from my wheels is very durable. I do have CBN wheels from D Way, and the CBN wheels leave a burr that is far superior to the burr from aluminum oxide wheels, white, pink, or blue.

You can burnish a burr if you want to, and it is done in a similar manner to card scrapers. Hone off the grinder burr, a few passes with the burnishing tool at about 90 degrees to the top/flat surface of the tool, which is about the same angle as you use on the card scrapers. I do get a better burr with a triangle burnisher as opposed to the round burnisher. Lee Valley tools makes a bench top screwed down/bolted down burnisher thing which works. I had one guy tell me that you can't hand burnish a burr on M2 high speed steel. Well, maybe I can armstrong it better than most, but it does not take much effort. A burnished burr does give a slightly finer cutting edge than the burr from the grinder.

You can hone a burr on the scraper by honing off the grinder burr, then honing the bevel. This produces a very fine cutting edge suitable only for ultra light clean up cuts. gone in seconds.

I have heard people claim that a scraper will not cut without a burr. Well, why did the hippy cross the road? Because some one told him not to. It actually cuts fine. There is no advantage to removing the burr.

For standard bowl turning, the scraper makes an excellent roughing tool. Great for removing vast amounts of wood in a hurry. Left flat on the tool rest, you will get more tear out. Up on edge, you can get a fine finish cut. You can actually do bevel rubbing cuts with it.

http://www.youtube.com/watch?v=hKdqiAc0jx4&feature=g-upl&context=G299f5d6AUAAAAAAADAA

robo hippy

[Richard Jones]

I also sharpen face up.

My name is Richard, and I use a scraper.

[robert baccus]

Ya'll listen to Wally now. we old graybeards earned our scars and wisdom and he's forgot more than most of us will learn in 10 years!---------------old forester

[Russell Neyman]

I know there are purists out there who claim they never, ever use scrapers or even use a gouge to make a scraping cut, but I do and get good results. I'm in complete agreement with Reed on this one.

As I tell my students, find out what works for you and do that. On some types of wood -- dry, hard maple, for example -- scrapers create too much tearout, but for wet turning a scraper works just fine. In fact, I use scrapers to hog out the interior in a hurry.

[Joe Hillmann]

Important side-note; when you talk about a ragged surface, I have to ask what way you are presenting the tool, was it wet or dry wood, and on the rim or in the bottom, or outside of a bowl surface?


I was just playing with a section cut out of a 2x4 turning it like you would a spindle. The scraper was held flat against the tool rest, I tried rotating it and using it more like a skew chisel but anytime it would catch it would zip off to the side and leave a nice spiral gouge in the wood. I tried it above and below center, I don't really remember which way worked better.