Grinder angle setup / Raptor setup tools

Discussion in 'Woodturning Discussion Forum' started by Mark Hepburn, Oct 19, 2016.

  1. john lucas

    john lucas

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    If your a member of the AAW your not a black sheep. You just do things differently. We try to learn from each other.
     
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  2. Mark Hepburn

    Mark Hepburn

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    Yep. What John said...
     
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  3. Jamie Straw

    Jamie Straw

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    Marc, I pretty much follow Dave Schweitzer's instructions for use of the Verigrind and Wolverine stuff, and my gouges are very consistently ground. I have marks on the Verigrind holder for where the leg is set for both bowl gouges and spindle gouges. I use a dowel of a specific length to set the V-pocket from the wheel (actually, from the socket for the V-pocket -- with a CBN wheel, I don't need to measure to the wheel but once). I have a wood block with a hole in it, the depth of the "stick-out" I use for the gouge (in my case, 1-7/8"). As long as the stick-out and the pocket-to-wheel distance are consistent, and the jig leg is set properly, the grind is consistent.

    Of course, I don't use much of a variety of grinds like the advanced users here do, but certainly could with this approach. One can of worms I've yet to open here on the forum is the fact that, if you watch different videos of sharpening instructions, you'll find differing opinions on what the pocket distance affects and what the leg-setting affects. Dave's statement on his videos and in person is that the grind of the tool's nose and a very small area on either side of the nose is set by the leg position, and the pocket distance affects the side grind. Given his experience as a machinist and his rather dazzling spatial abilities, I've bought his version.

    His videos, best to watch in order -- the 2nd one assumes you know what's in the first. These and a bit of time in his shop turned my sharpening life around!:


    View: https://www.youtube.com/watch?v=uxdLXsFl01s


    View: https://www.youtube.com/watch?v=XdF9mmJtuvU


    D-way Tools

    [OK, I didn't know that putting those links in would embed the videos. Too much like Facebook, LOL!]
     
  4. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I agree. Each of us does things a little differently. That's why you see such a diversity of opinions when a question is asked about almost anything.. When it comes to sharpening. I'm more "different" than Odie since I am a Tormek sharpener for 99% of my woodturning tools.

    BTW, Odie, a large gathering of sheep is a "flock". :D
     
  5. hockenbery

    hockenbery AAW Advisor Staff Member

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    We all have different experiences and sharing is what it's all about.
     
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  6. Dennis J Gooding

    Dennis J Gooding

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    I too use pieces of ¾-inch or 1-inch PVC tubing to gauge the V-arm position when using the vari-grind jig. However, I slot the tubing length-wise so it will drop down over the arm rather than having to be threaded over the arm. If one uses a fixed arm angle setting, and a fixed value of gouge protrusion from the jig, then V-arm setting uniquely determines the nose angle that is achieved whether it is a spindle gouge, a detail gouge or a bowl gouge. I mainly use four nose angles and require only four pieces of tubing. However, if I should decide to add a fifth angle, it would take only a couple of minutes to cut and slot another piece of PVC.

    To make life easier, when I set up my V-arms, I set one arm as specified in the instructions and then tweeked the position of the second arm so that a given piece of PVC yielded the same nose angle for both wheels. Otherwise, I would have had to make a separate set of gauges for the two wheels.
     
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  7. Tom Gall

    Tom Gall

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    Just like Dennis, I have used lengths of PVC tubing (whatever ID I have available) and/or wood dowels to set the arm of the Wolverine jig. However, I don't slot the tubing. I just put one end IN the pocket and slide the arm forward until the other end butts up against the jig where the sliding arm enters and then lock the arm. Quick & simple and any size ID tubing/dowel can be used.
    And being the lazy guy that I am…..about 10 years ago I bought a second Vari-Grind jig, so I now have one permanently set for bowl gouges and the second set for spindle gouges…..therefore, using the same arm setting for both. :)
     
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  8. Mark Hepburn

    Mark Hepburn

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  9. Dave Delo

    Dave Delo

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    I've gone to sharpening all my bowl gouges with the 180 grit CBN and have different angles ground on several gouges. I find the Raptors 3-point contacts make it a fast, easy, repeatable and very accurate for changing the V-arm length. Yes, you can make your own and if that's what one wants to do, go right ahead.

    I used Robo's rest at 45 degree setting to get a 41.5 degree angle for my so called 40/40 grind and use the 75 degree setting for the bottom feeders.

    In some ways I'd like to have 2- 180 grit wheels but I do prefer the burr from the 80 grit wheel for my hollowing scrapers.
     

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  10. Chuck Lobaito

    Chuck Lobaito

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    that's genius
     
  11. Paul A Andrews

    Paul A Andrews

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    Interesting. That's pretty much what David Ellsworth said when he was here in the Spring doing demos. Black sheep who marches to the beat of his own drum.
     
  12. Dennis J Gooding

    Dennis J Gooding

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    I agree with the almost unanimous opinion that there are better options than the Raptor tool. I use the PVC gauge method and because I use a fixed arm angle for the jig and a single gouge protrusion value, I only need one PVC gauge for each nose angle that in my arsenal, regardless of whether it is a spindle gouge, detail gouge or bowl gouge. A further problem with the Raptor tool is that it gives the correct nose angle only if the jig arm angle is set to 23 degrees. In my opinion, this much too small an angle to achieve a satisfactory sharp long wing on my bowl gouges. I set my arm at the third notch, or about 40 degrees.
     
  13. john lucas

    john lucas

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    I use a homemade tool that I designed way before Raptor's were ever thought of. My design came from a more complicated version by Mike Darlow. I use 1/4" luan plywood. I simply make a triangle with one leg that fits the V arm and the other side goes next to my grinder wheel. The V arm is set for the proper distance for the tool I'm makeing the jig for. I draw an arc to match the wheel and then draw a smaller arc so that it leaves just 2 points touching the wheel. That gives me 3 point contact of the wheel. I used to make one for each tool grind but I find that my spindle gouges and bowl gouges I grind the same way I just use a different nose angle so I put a V block of wood into the Oneway V to move the Wolverine jig forward. This gives me a 35 or 45 degree nose angle depending on which block I put in and a 55 degree angle for the bowl gouge. I never move the V arm so my grinds are duplicated each time. Here is a video that shows the jigs although I now just use a V block of the proper length and put the wolverine jig against it instead of sitting in a carved slot on top like in this video.

    View: https://www.youtube.com/watch?v=Xbggxj2kgyc&t=6s
     
  14. Fadi Zeidan

    Fadi Zeidan

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    John,

    How did you determine the initial size of the block or the 3 point templates? Trial and error?
     
  15. john lucas

    john lucas

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    Lately I have changed a little bit my sharpening methods. I am standardizing some grinds so that I don't have to change the settings on my jigs. I am using the Robo-Rest on one side and it's set to 40 degrees. I hand sharpen my Spindle roughing gouge, Stewart Batty ground gouge, my mini ornament tools, and my negative rake scraper, and skews on that. This side has a 120 grit white wheel. I use my Wolverine jig with the V arm locked down on the other side that has a CBN wheel. I do my bowl gouges both V and U on that and it's set up to give me roughly a 55 degree bevel. I sharpen my spindle gouges with exactly the same set up but simply put a block in the V arm to move them closer which changes the nose angle to a more acute grind.
     
  16. Fadi Zeidan

    Fadi Zeidan

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    Thanks John.

    What I’m trying to understand is that if I have the v arm set for 60 degree grind, how much do I raise it via a block or move it forward to get to 40 or 30 grind. Only way I know how is to move it a little, grind and measure. Trial and error basically. Once the angle is found, mark it for repeat use. Is that what everyone does?
     
  17. john lucas

    john lucas

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    I cheated. I had my spindle gouges ground to angle I liked so I simply put them in the Wolverine jig and moved them forward in the V arm until the bevel was flat. Measured this distance and made a V block that long to sit in the V arm.
     
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  18. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Raising it increases the angle and moving it forward decreases the angle. How much depends on the geometry of your set up. It would be necessary to know the exact wheel diameter and the vertical distance from wheel center to the v notch.

    You can get eyeball close by holding a small plastic triangle next to the tool while sighting from the side and sliding the V arm. My opinion is that there isn't anything magic about getting a precise angle when first creating a grind. With subsequent sharpening, of course, it is important to set the angle right in order to minimize grinding. You can do this by coloring the bevel with a Sharpie. You can also do this by sighting from the side and looking at the light gap, but it's not quite as precise.
     
  19. Dennis J Gooding

    Dennis J Gooding

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    The issue of the Raptor setting gauge has come up several times recently There are a couple of problems with it. First, it costs money. John Lucas has showed how to make the equivalent for free. More importantly, it gives the indicated nose angle ONLY if the varigrind arm angle is set to 23-degrees and the gouge protrusion is 2.5-inches (or a combination of values of these parameters that places the nose of the gouge at the same position and angle). As mentioned by others, other mounting parameters do not matter as long everything remains within adjustment limits and freedom of movement is preserved. I have reservations about both the 23- degree choice for arm angle and the 2.5 inch gouge protrusion.

    The arm angle has very little effect on the character of the grind obtained as long as the fingernail is short--say equal or less than the diameter of the gouge. An arm angle of 23-degees will produce about the same results as an angle twice as large. This is a matter of geometry. When grinding a short bevel, the jig does not have to be rocked very much from side to side, so the arm angle does not have much effect. However, if you want to produce a long side-grind on a gouge, say 1.5 diameters or more, the 23-degree arm angle will yield a rather blunt edge at the end of the wing. For that reason, many turners, including myself, have chosen a larger arm angle for use with all spindle and bowl gouges. Dave Thompson has set a sort of de facto standard of about 43-degrees (the fourth notch on the arm angle scale) for all of his gouges, and I have followed suit.

    The specified gouge protrusion value of 2.5 inches fodr the Raptor gauge is 0.75 inches longer than the more commonly recommended value of 1.75 inches. This means that a gouge will have 0.75 inches shorter life before it must be discarded or treated as a special case in the sharpening setup. There is no advantage in the longer value, because any reasonable change in the protrusion value can be exactly compensated by changes in the V-arm position and to a lesser degree, the arm angle. Note however, that setting the protrusion to values much less that 1.75 inches may lead to the varigrind jig hitting the grinding wheel.
     

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