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Thread: New (to me) Negative Scraper

  1. #1

    New (to me) Negative Scraper

    I am fairly new to turning and have been finding that I really like using skew chisels a lot, so a negative rake scraper seemed like a good tool to buy. I picked up a used Benjamin's Best at an auction of a deceased turner's stuff and I really love it. At $5 I figure it was a great deal.

    Is there any jig that makes it easier to sharpen or is it best to just free hand it? I do my gouges on my Grizzly Tormek clone with a home made jig, but that jig isn't suited to the scraper.

  2. #2
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    how I sharpen NRS

    Pete,

    I sharpen all of mine the same way, either small round scrapers, flat and straight edge, or large curves. I set a flat tool rest on a grinder to the desired angle and sharpen freehand exactly like I do a skew - sliding or rotating as needed to follow the profile with the shaft pressed tightly into the rest.

    I sharpen my spindle gouges on the Tormek (1200 grit CBN) but I sharpen the skews and scrapers on a 600 grit CBN on a 1/2 speed grinder. The skews are honed afterwards but the scrapers are used off the grinder at first. When the burr wears away I hone off any remaining burr then raise a new burr with either a carbide burnishing rod or a fine diamond hone (the blue one below) if I want an extra wispy shaving.

    burnisher_IMG_6767.jpg hones.gif

    These are some of what I use for smaller things like end grain boxes and for detail on face turnings, ground from Thompson steel, one ground from a detail gouge.

    scrapers_small_thompson.jpg

    I use these on bowls, platters and such, ground from Thompson scrapers and a skew chisel. I usually keep them sharpened and with burrs for both left and right hand use.

    scrapers_neg_rake.jpg

    JKJ

    Quote Originally Posted by Pete Staehling View Post
    I am fairly new to turning and have been finding that I really like using skew chisels a lot, so a negative rake scraper seemed like a good tool to buy. I picked up a used Benjamin's Best at an auction of a deceased turner's stuff and I really love it. At $5 I figure it was a great deal.

    Is there any jig that makes it easier to sharpen or is it best to just free hand it? I do my gouges on my Grizzly Tormek clone with a home made jig, but that jig isn't suited to the scraper.

  3. #3
    That makes sense. Thanks.

  4. #4
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    I have the Tormek flat tool rest. If you don't have one I would suggest getting it. I think it's the SVD-110. I think either that or the one that comes with the grizzly that you can clamp a flat tool should work. The Tormek rest clamps very well to the support rod.

  5. #5
    I took the two bars off the rest for the scissors sharpener in the Grizzly kit and found it makes a reasonable substitute for the SVD-110. I can do pretty well with it, much better than the previous owner of the chisel did with whatever he used judging by the condition it was in when I got it. I find it now works well and is quick and easy to touch up.

    I am sure it will work great for my skews as well.

    Thanks for the suggestions.

  6. #6
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    JKJ, how do you keep an even curve on the scrapers during sharpening? Is it just more practice, as I seem to get multiple facets.
    Richard.

  7. #7
    Quote Originally Posted by Richard Casey View Post
    JKJ, how do you keep an even curve on the scrapers during sharpening? Is it just more practice, as I seem to get multiple facets.
    Richard.
    Just me, and I am a beginner at this trying to follow Richard's advice, but maybe the beginner perspective can be useful. I am finding that with a nice flat rest at the right angle I can concentrate on following the curve and get one nice continuous face. For me it seems to help to concentrate on finger tips holding the tool on the rest and not using the handle.
    Last edited by Pete Staehling; 09-07-2018 at 6:39 AM.

  8. #8
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    Quote Originally Posted by Richard Casey View Post
    JKJ, how do you keep an even curve on the scrapers during sharpening? Is it just more practice, as I seem to get multiple facets.
    Richard.
    Like Pete, I usually hold the tool and not the handle. Actually, it's easy in my case since most of my tools can be removed from the handle. And what I call "finishing" scrapers (not used for hollowing boxes, etc.) never get put into handles - there is no force and no need. That said, if sharping a skew or scraper with a permanent handle I simply press harder with the upper thumb to hold it tightly against the rest.

    I press the tool into the flat rest with one finger or thumb near the top and with the thumb of the other hand near the bottom. The top point is more-or-less the pivot and the bottom hand rotates the tool. This is the same way I sharpen skews too, the straight edge one by sliding across the wheel and the curved ones by pivoting. The pivot point does have to change during the sharpening on most curved-edge tools, unless it's a symmetrical round-nosed scraper.

    One thing that helps is a smooth/slick tool rest! The stock Wolverine rest surface is too rough for sliding evenly, tending to leave a less smooth bevel and edge. You can take some fine sandpaper to it, wax it (and maybe the tool), add a thin sheet of nylon or something, or use a different rest. One of my Tormek rests has a slick surface so I often use it. I added a base to use the Tormek support bar with my 600 grit CBN wheel (here on the old radiused-edge wheel I don't use anymore!)

    tormek_B.jpg

    Another thing I don't like about the standard Wolverine rest is it's too big! Instead, I use the "mini" rest which apparently a lot of people have never heard about! This is great, especially for smaller tools and handled tools that have been sharpened till they are too short to fit on the standard rest. The bottom edge is radiused as well making it easier to hold and pivot the tool with the lower hand.

    https://www.hartvilletool.com/produc...eway-wolverine
    3655_1173_popup.jpg

    All that said, I don't worry if a bevel doesn't look perfect as long as the edge is perfect. And for skews, I hone anyway so minor imperfections in the bevel close the the edge are removed. The hardest skews for me are those with the oval shafts - straight edge is no problem but a curved-edge oval skew takes me several tries and seldom looks perfect!

    JKJ

  9. #9
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    I looked at the scissor jig from Grizzly. I liked that the two rails were long but it looked like when I sharpen my bowl scraper it would loose contact with the outer rail as I was trying to sharpen the side. When sharpening it I go from perpendicular to past parallel to the grinding wheel. That's why I went with the flat rest from Tormek. Before that, by hand, it was too hard to get a consistent grind.

  10. #10
    Quote Originally Posted by Alex Zeller View Post
    I looked at the scissor jig from Grizzly. I liked that the two rails were long but it looked like when I sharpen my bowl scraper it would loose contact with the outer rail as I was trying to sharpen the side. When sharpening it I go from perpendicular to past parallel to the grinding wheel. That's why I went with the flat rest from Tormek. Before that, by hand, it was too hard to get a consistent grind.
    The Tormek looks like a very nice rest so I am sure it is a good purchase.

    That said I am happy with the scissor jig. The key is that I removed the round bars and just use the remaining flat plate. That way I get good contact throughout. What remains is functionally somewhat equivalent to the SVD-110. Maybe not as nice, but it serves the purpose, a flat surface that can be adjusted to the correct angle. If I ever want to use the scissor jig for it's original purpose I could bolt the bars back on.

    I tried using it to sharpen my negative bowl scraper with the bars on and it was a big fail, but with them removed it works fine.
    Last edited by Pete Staehling; 09-07-2018 at 2:56 PM.

  11. #11
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    Just a thought but is sounds like you have your hand too far down the handle and inadvertantly pressing down and lifting up the edge. Also not pressing down on the scraper to keep it flat on the grinder grinder too rest.
    God is great and life is good!

  12. #12
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    Quote Originally Posted by Pete Staehling View Post
    The Tormek looks like a very nice rest so I am sure it is a good purchase.

    That said I am happy with the scissor jig. The key is that I removed the round bars and just use the remaining flat plate. That way I get good contact throughout. What remains is functionally somewhat equivalent to the SVD-110. Maybe not as nice, but it serves the purpose, a flat surface that can be adjusted to the correct angle. If I ever want to use the scissor jig for it's original purpose I could bolt the bars back on.

    I tried using it to sharpen my negative bowl scraper with the bars on and it was a big fail, but with them removed it works fine.
    It's hard to see from pictures that the bars come off easy. That would make it more useful.

  13. #13
    Quote Originally Posted by Alex Zeller View Post
    It's hard to see from pictures that the bars come off easy. That would make it more useful.
    Yes, they come off (and go back on) very easily. Removing two allen head cap screws per bar is all that it takes to remove the bars. I was debating between ordering the Tormek SVD-110 and building something when I realized that the the bars were easily removed and the scissor jig worked fine once they were removed.

  14. #14
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    I had thought about trying to make something flat that could mount to the top bars as I like the idea of being able to clamp thinks like scissors but didn't want to mess up it's functionality. In the pictures you can see what looks like threaded holes and screws that held the bars in place but not seeing it in person means taking a chance. What sold me on the Tormek was the fact that I had the Tormek gouge jig and it works great. I have a block of wood with a hole in it that I can side it onto the bar so I can set the distance between it and the grinding wheel and another hole that's drilled to the exact depth for the jig to mount onto the gouge. In seconds I can be touching up my gouge.

  15. #15
    Quote Originally Posted by Alex Zeller View Post
    I had thought about trying to make something flat that could mount to the top bars as I like the idea of being able to clamp thinks like scissors but didn't want to mess up it's functionality. In the pictures you can see what looks like threaded holes and screws that held the bars in place but not seeing it in person means taking a chance. What sold me on the Tormek was the fact that I had the Tormek gouge jig and it works great. I have a block of wood with a hole in it that I can side it onto the bar so I can set the distance between it and the grinding wheel and another hole that's drilled to the exact depth for the jig to mount onto the gouge. In seconds I can be touching up my gouge.
    If I didn't already own the Grizzly stuff I might have bought the tormek, but I bought the "accessory kit #1" with the grinder and it included the scissor jig.

    BTW, I have been experimenting with which side of the grinder to sharpen the various tools on. I have found that I like to sharpen the gouges on the back side (with the face of the wheel going up) and the skews and scrapers on the front. That has the fortunate advantage of allowing me to leave the front set up for skews and the back for gouges. The grinder is on a turntable so I just spin it 180 degrees and lock it down.

    With that setup... I find that the gouges don't cause the face of wheel to get wear grooves or go concave so fast if at all. I also find that the skews and scrapers tend to stay flat on the rest more easily. I spend almost no time truing up the wheel and very little time setting up jigs. It winds up being way lower maintenance in my limited experience and I have found no downside.

    I have not lived with the completed setup long yet (just finished the turntable), but so far it seems very promising.

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