D.H.Phillips
Active member
I feel like I am having to sharpen my card scraper too often. What is the realistic life expectancy of a good burr???
card scraper burr life
- Thread starter D.H.Phillips
- Start date
Dan,
I do not have a hard number in mind because my experience with scrapers is limited.
However, I might think if you were having trouble keeping the burr, something may have happened to lessen the physical properties of the steel. This is all to easy to happen, and if you did not buy the tools new, one never knows where they have been, or who used a grinder on them.
Karl
I do not have a hard number in mind because my experience with scrapers is limited.
However, I might think if you were having trouble keeping the burr, something may have happened to lessen the physical properties of the steel. This is all to easy to happen, and if you did not buy the tools new, one never knows where they have been, or who used a grinder on them.
Karl
Antiquity
Well-known member
Dan,
I use card scrapers all the time. Many factors can dull the edge quickly. Removing an old finish will do it very fast. Sometimes when you sharpen the scraper one or more of the four edges will not get as sharp as the others. This edge will then dull faster. Sometimes your scraper will cut great when held at a, say, 45° angle while other times it cuts best when almost parallel to the board.
If I am scraping a dining table top, 36" x 72", I will have to sharpen all four edges several times. It also depends on the wood. Hard maple will dull the edges faster than mahogany.
Hope this helps.
Dennis Bork
Antiquity Period Designs, Ltd.
I use card scrapers all the time. Many factors can dull the edge quickly. Removing an old finish will do it very fast. Sometimes when you sharpen the scraper one or more of the four edges will not get as sharp as the others. This edge will then dull faster. Sometimes your scraper will cut great when held at a, say, 45° angle while other times it cuts best when almost parallel to the board.
If I am scraping a dining table top, 36" x 72", I will have to sharpen all four edges several times. It also depends on the wood. Hard maple will dull the edges faster than mahogany.
Hope this helps.
Dennis Bork
Antiquity Period Designs, Ltd.
Mickey Callahan
Well-known member
Hi Dan,
First, it would be interesting to know how you routinely sharpen your scrapers? The usual question I receive from my students is how often does one have to sharpen their tools? The simple answer is when they get dull. However, it's important to be consistent with how you sharpen your various hand tools, scrapers being one of them. It's already been pointed out that it also depends on the wood species or if any finish is present. I have discovered that many woodworkers don't master the importance of surface preparation (both edge and adjacent face) before they burnish and draw the hook onto the edge. Another factor is how much of a hook has been created and to what angle it projects from the main body. The combination of proper surface preparation, correct burnishing with a polished and harden steel rod at the proper angle, and just the right pressure will generally produce consistent results. Also keep in mind that as you re-sharpen numerous times, metal fatigue starts to come into play meaning that the scraper will not perform as well, dull quicker, and ultimately means you go back to square one and start the complete sharpening process all over again.
If a card scraper has been properly prepared, it should work where it is being held close to vertical, plus the hook is just noticeable if your were to run your finger nail across the edge without it being completely stopped by the hook. The bigger the hook, it is more likely to fail sooner because there is little to support it. A bigger hook is also an indicator that you probably burnished at a more steep angle away from the vertical and thus created a weaker hook. This condition is easy to determine if you need to have the scraper working at an angle that is closer to being parallel to the work surface. Let us know how you make out if any of this discussion has been helpful.
Mickey
First, it would be interesting to know how you routinely sharpen your scrapers? The usual question I receive from my students is how often does one have to sharpen their tools? The simple answer is when they get dull. However, it's important to be consistent with how you sharpen your various hand tools, scrapers being one of them. It's already been pointed out that it also depends on the wood species or if any finish is present. I have discovered that many woodworkers don't master the importance of surface preparation (both edge and adjacent face) before they burnish and draw the hook onto the edge. Another factor is how much of a hook has been created and to what angle it projects from the main body. The combination of proper surface preparation, correct burnishing with a polished and harden steel rod at the proper angle, and just the right pressure will generally produce consistent results. Also keep in mind that as you re-sharpen numerous times, metal fatigue starts to come into play meaning that the scraper will not perform as well, dull quicker, and ultimately means you go back to square one and start the complete sharpening process all over again.
If a card scraper has been properly prepared, it should work where it is being held close to vertical, plus the hook is just noticeable if your were to run your finger nail across the edge without it being completely stopped by the hook. The bigger the hook, it is more likely to fail sooner because there is little to support it. A bigger hook is also an indicator that you probably burnished at a more steep angle away from the vertical and thus created a weaker hook. This condition is easy to determine if you need to have the scraper working at an angle that is closer to being parallel to the work surface. Let us know how you make out if any of this discussion has been helpful.
Mickey
Mo Yarborough
Well-known member
Hi Dan... I would like to echo what the others have been saying, and add a few thoughts. I began my woodworking career starting out as a trained Blacksmith in order to make and understand the tools I would
be working with for a fine finish..without sanding. As with the tempering of a knife blade, or lock spring
for a rifle, the tempering of chisels, plane blades, and card scrapers is vital. In addition, the aggresiveness of the burnisher for applying the appropriate edge on the scraper is key along with surface preparation.
I have card scrapers that I have made from all types of steel. I have some that were purchased. The most
aggressive one I have is cut from a 3/16" BandSaw Mill Blade, and I left this one with the original temper. I burnish it with a smooth ground triangle file (all file marks are gone with the surface polished). The file is 1095 steel and has it's manufactured temper. The combination of the Bandsaw Scraper and File Burnisher creates an aggressive edge for fast material removal...and depending on the edge roll I create( burr), it can be held almost vertical or at a more aggressive angle...it all depends on how well I prepared the surface and the burr, and how aggressive I want it to cut. If I am scraping paint or Resins...I have to sharpen it when I feel it is dull.
Another scraper is made from an old handsaw, and it would be similar to a Lie-Neilsen scraper. I use a Carbide Burnisher to prepare my burr. I use this scraper for surface finishing.
Several years ago I found an old VHS video that was produced by the College of the Redwoods back when James Krenov was teaching. It was a student video featuring Ron Hock and others; the focus was on tools. The method they used then, and is used now by many, including you I'm speculating, is the way the scraper is prepared. On the video they used Japanese Water Stones to prepare the scraper by laying it flat and working off the previous burr. The scraper edge was then polished on the 800 and 4000 grit stones and then the burr created using a Carbide Burnisher. One young man was showing how he used three different aggressive scrapers to finish the top of a Walnut Dining Table, with the last scraper having a fine burr. Made sense to me, and the table surface was beautiful.
I hate sanding...
Mo
be working with for a fine finish..without sanding. As with the tempering of a knife blade, or lock spring
for a rifle, the tempering of chisels, plane blades, and card scrapers is vital. In addition, the aggresiveness of the burnisher for applying the appropriate edge on the scraper is key along with surface preparation.
I have card scrapers that I have made from all types of steel. I have some that were purchased. The most
aggressive one I have is cut from a 3/16" BandSaw Mill Blade, and I left this one with the original temper. I burnish it with a smooth ground triangle file (all file marks are gone with the surface polished). The file is 1095 steel and has it's manufactured temper. The combination of the Bandsaw Scraper and File Burnisher creates an aggressive edge for fast material removal...and depending on the edge roll I create( burr), it can be held almost vertical or at a more aggressive angle...it all depends on how well I prepared the surface and the burr, and how aggressive I want it to cut. If I am scraping paint or Resins...I have to sharpen it when I feel it is dull.
Another scraper is made from an old handsaw, and it would be similar to a Lie-Neilsen scraper. I use a Carbide Burnisher to prepare my burr. I use this scraper for surface finishing.
Several years ago I found an old VHS video that was produced by the College of the Redwoods back when James Krenov was teaching. It was a student video featuring Ron Hock and others; the focus was on tools. The method they used then, and is used now by many, including you I'm speculating, is the way the scraper is prepared. On the video they used Japanese Water Stones to prepare the scraper by laying it flat and working off the previous burr. The scraper edge was then polished on the 800 and 4000 grit stones and then the burr created using a Carbide Burnisher. One young man was showing how he used three different aggressive scrapers to finish the top of a Walnut Dining Table, with the last scraper having a fine burr. Made sense to me, and the table surface was beautiful.
I hate sanding...
Mo
D.H.Phillips
Active member
Thanks guys for taking the time to think about it. It sounds to me like the frequency at which I am having to sharpen the tool is pretty normal. I recently finished a table top that was 30 wide by 5 feet long. The scraper was doing an excellent job. It just seemed like stopping to burnish the edge every ten minutes or so seemed a bit much. I probably put the tool to the stone two times during the process. I rub the two faces and the edge on an oil stone, drag a mill file down the edge, hone that again on the stone, and then burnish. Most of the time the hook is right on but sometimes it gets too big. Cuts wonderfully with the big hook but that edge won't last very long. The scraper I use most is an old one. It is thick compared to other ones I have.
anyhow....thank you for the input. I think I am just wanting the edge to last longer than is reasonable.
- Dan
anyhow....thank you for the input. I think I am just wanting the edge to last longer than is reasonable.
- Dan
Mo Yarborough
Well-known member
Dan ...every project is different, and we as Humans are different every day when working with our projects.
Sometimes I sharpen things great one day..and the next not so great. The greatest blessing you will give yourself is NOT to over burnish your scraper for a burr. If the metal of the scraper is tempered to light blue or slightly maleable it will burr easily. Burnishing with equal pressure and a smooth stroke at 10 or 20 degrees will bring forth a fine and consistant burr. It will dull after aggressive use, which brings up the reason to have several scrapers that are individually aggressive to get the desired result!
Mo
Sometimes I sharpen things great one day..and the next not so great. The greatest blessing you will give yourself is NOT to over burnish your scraper for a burr. If the metal of the scraper is tempered to light blue or slightly maleable it will burr easily. Burnishing with equal pressure and a smooth stroke at 10 or 20 degrees will bring forth a fine and consistant burr. It will dull after aggressive use, which brings up the reason to have several scrapers that are individually aggressive to get the desired result!
Mo
Jeff Saylor
Well-known member
I recently obtained some used bandsaw blade stock from a pallet shop. The steel is tremendous for scrapers. It's thicker than any scraper I've purchased (.050"). I have some Disston's (.035) and a Lie Nielson (.020) that don't compare to the edge holding of this material. When I got the blade, I had to use a steel cutting chop saw to cut it into pieces and then cut off the saw teeth. The tooth edge was hardened to the point that when I first cut it off, a file wouldn't cut the last 1/16" so I had to cut it back a little more (rather than mess with the temper). Now they work great. Also, they are excellent for use in a Stanley 80 cabinet scraper- thicker means less chatter!
Most people, especially in the beginning put too big of a burr on a scraper and at too great of an angle. Alight touch at a slight angle is the ticket. Ofentimes you can use the burnisher put a new burr on without re honing the scraper, just re-do the burnishing portion.
Mo Yarborough
Well-known member
Jeff...you are right..the used up Mill Bandsaw Blades from commercial mills are great scraper material. In addition, old or worn out 10" and 12" circular saw blades can be cut on a metal cutting chop saw to make scrapers. The thickness is great and most all are of a quality tool steel. They will have been tempered at the factory with a hardness not quite right for scrapers, but, the act of cutting them on the chop saw and then cleaning the edge on a grinder or 2" x 72" belt sander re-tempers the blade just enough to put a crisp edge on the scraper making it easy to file and polish...producing a sharp burr. And they hold the burr longer!
It was my Jr. High School Industrial Arts Instuctor who passed on a spirit to me in the 8th grade that has kept me working with metal and wood the balance of my days! That was in 1962! What a journey it has been! We should get together sometime as I see that Hunting, Fishing, making furniture, and going to Flea Markets searching for old tools has also been a method of distraction and peace for decades!
It was my Jr. High School Industrial Arts Instuctor who passed on a spirit to me in the 8th grade that has kept me working with metal and wood the balance of my days! That was in 1962! What a journey it has been! We should get together sometime as I see that Hunting, Fishing, making furniture, and going to Flea Markets searching for old tools has also been a method of distraction and peace for decades!