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Thread: For all the hollow grinders (and anyone else) out there

  1. #1
    Join Date
    Nov 2019
    Location
    Big Bend/Panhandle, FL
    Posts
    24

    For all the hollow grinders (and anyone else) out there

    If I had the option of a subtitle for this thread, it would definitely be:

    "If not for the free time in my schedule and the free shipping offered by Lee Valley, none of this would be happening."

    Hi all. Like many, I have found myself with a little extra time on my hands lately, which has led to a re-evaluation of how I sharpen my plane irons and chisels. I took the hand tool plunge because I like my fingers attached and I really enjoy the sweet serenity of silence. After ogling over some of the images of precision hollow ground chisels and plane irons on the Creek and elsewhere and looking for a slightly faster way to grind and/or change primary bevels, and improve my freehand sharpening, I decided to dust off my much neglected 6" variable speed Delta bench grinder and invest in a tool rest and jig from Lee Valley. The grinder wheels are stock wheels, but spin true. Much to my surprise, the old grinder has almost no run out! Off to a good start!

    I installed the tool rest according to the instructions with the tool rest 2 inches from the base of grinder and square to the grinding wheel. I set the angle I was shooting for by using the included angle setting thingamajig and double checked its accuracy with a protractor. (I am so glad I paid attention that one day all those years ago in geometry class!) Installation was straight forward, but that is where my joy ended. Attached are my three test attempts on some cheap chisels of varying sizes. Something is amiss.

    For starters, it took a long time. I think I could have reground the primary bevel faster on coarse sandpaper. I properly dressed the wheel prior to starting so I do not think it was a case of wheel glazing, but not certain. The perplexing thing, one of them anyway, was my inability to grind a complete hollow. I managed to get close with chisel three, but I just could not get a full regrind. Also, has anyone else had issues with the jig not grinding square? The tool rest is square to grinder and the chisel is placed in the jig firmly against the alignment pin.

    I know there are several older threads that deal with this particular tool rest and jig, but I thought I would ask for thoughts, let everyone "admire" my handiwork, and hopefully get some pointers on how to properly use the tool rest and jig.
    Chuckles on me tonight! Thanks. chisel 1.jpgchisel 2.jpgchisel 3.jpg

  2. #2
    Join Date
    Jan 2017
    Location
    Santa Cruz, CA
    Posts
    78
    Looks to me like you are not done grinding the hollow yet. I suspect that your wheels aren't cutting the steel very well. Hard to say without knowing what kind of wheels that you are using. As far as square, even with a good jig, or rest, I think you still have to check your progress and make sure that you are getting a square edge. Have a square handy and check your progress as you go. Hope that helps. Maybe order a new grinding wheel? I have a 180 CBN wheel and its dope.

  3. #3
    Join Date
    Dec 2017
    Location
    Plano, Tx
    Posts
    132
    Have you checked the bevel angles after grinding with a protractor or angle gauge (not sure if that is the right name - the little brass wheel with cut out notches for different bevel angles)? I had difficulty setting my grinder rest up with the included Veritas jig.

    Ultimately, I resorted to taking one of my chisels that I had verified a 25 degree bevel on and using it to set the angle of the rest. The way I read to do so was to set the tool on the rest with the bevel on the wheel and eyeball it so that the wheel contacts the middle of the bevel. Give the wheel a spin by hand and then look at the scratches on the bevel. If they are in the middle of the bevel then it is at approximately 25 degrees.

    I admit that isn't a fool proof nor long term method but it has worked for me for now and i do occasionally verify with an angle gauge thingamabob.

  4. #4
    I used a chisel that I had with a 25 degree stock bevel to set my jig/rest as well and havenít touched it since. Also I scrapped the guide that rides in the rest and it seems to work better. I believe Rob Cosman has a video on hollow grinding a plane iron that would help to understand how to best use the grinder and tool rest.

  5. #5
    Join Date
    Dec 2016
    Location
    South West Ontario
    Posts
    1,057
    Hollow grinding can be a big time saver on thick plane blades and I suppose large chisels, though there are other options. I have not done it on chisels. Your hollow grinding seems off square, you have destroyed the front edge on one.
    The idea is to not touch the front edge or the back edge just create a small depression in the middle to reduce sharpening time. Take it slow, check the position and squareness, then stop when you have a depression. If you destroy the edge you have to re-establish the main bevel, you may not save much time!
    ​You can do a lot with very little! You can do a little more with a lot!

  6. #6
    Join Date
    Aug 2019
    Location
    Pittsburgh, PA
    Posts
    120
    Is this the tool you're using?

    https://www.leevalley.com/en-us/shop...nder-tool-rest

    Unless you are careful to move the blade left to right without swiveling it, you will get a hollow that is not 90 degrees with the long axis of the chisel. Also, as William above pointed out, don't grind the back of the bevel or the cutting edge.

    Rafael

  7. #7
    Join Date
    Jun 2008
    Location
    So Cal
    Posts
    2,641
    I also hollow grind some of my chisels but mostly my Plane blades because they are A2 .
    The easiest way to keep track of you squareness is to hold of the chisel and look at the back. Your eye will pick up the Side that looks longer.
    Good luck
    Aj

  8. #8
    Join Date
    Nov 2019
    Location
    Big Bend/Panhandle, FL
    Posts
    24
    William,

    Thanks for the response. I should have better articulated what I was trying to accomplish with these chisels. I wanted to establish a new primary bevel on all three of these chisels both for practice and because they really needed some work. These are the chisels that I bought when I was first teaching myself how to sharpen. While originally factory ground to +or- 30 degrees, by the time I took them to the grinder yesterday, they were off squared with multiple facets. The destruction was intended. I wanted to start fresh with new primary bevels on each chisel. I also wanted the hollow grind to aid when I honed these on the water stones. Either way, I had few minutes this morning and made second attempt with some progress...I think. Also, These have not been honed yet.

    Chisel 1.jpg Chisel 2.jpg

  9. #9
    Join Date
    Nov 2019
    Location
    Big Bend/Panhandle, FL
    Posts
    24
    Rafael,

    Yes that is the tool rest I have. The tool rest is solid, but the sliding jig that I purchased is a bit more finicky than I anticipated.

  10. #10
    I hollow ground all my irons and chisels. Iím actually going back and touching up a few because after two years of stropping and the occasional stoke, Iím losing the hollow enough to make it more difficult to get registration when freehand sharpening and also makes it take longer to sharpen.

    Looking at the Veritas jig for their tool rest, that looks like a problem causer rather than a problem solver. Thatís my one issue with Veritas is sometimes they go solving problems that donít exist and sometimes their solution just makes more of a problem than the original problem. Iíve been bitten before! Itís really no big deal to slide the iron reasonably straight across the tool rest. Maybe not the first or second iron, but by the third youíve got it down cold.

    I use a fat sharpie to color the entire bevel, then scratch on the wheel to find the center. The tool rest on my super cheap Craftsman grinder is a pain to adjust so if Iím close Iíll ďshimĒ with a piece of masking tape on the edge of the rest to micro-adjust the angle to get it dead center to my bevel. Then, when grinding, check after each pass. If a little too much has come off the left side, then just do the next pass on just the right side. Etc. You adjust as you go if things get a little wonky because nobody can drag a perfect 90 degrees.

    Touch ups are very fast. However, grinding an entirely new bevel on some heavily damage tool or a substantial bevel angle change are annoyingly slow processes.

  11. #11
    I use the LV tool rest on both wheels on my 7" grinder. I have used and will continue to use the tool holder with the rest when I feel that is will help me. I don't mind it but it has a loose fit to the tool rest and if you don't recognise and account for this you can get very frustrated. I almost always freehand because I have used this set up for years and have got the technique down reasonably well.

    I have yet to see a bench grinder sold with wheels worthy of sharpening garden tools. A proper wheel is so important. I don't have the specs on my wheels currently but I use 46 and 60 grits with a friable bond. The 46 grit gets the job done very quickly and the honing isn't tough. I don't use a star dresser very often but I rely on a single point diamond to true and clean up my wheels.

    I find that it is way more efficient to re-grind the hollow once the honed facets on the hollow grind are about 1.5mm to 2.0 mm than to continue to hone until the hollow is almost all gone. Once you have the touch with your grinder you won't be removing much material from your tools at all. Grinding is faster than honing inch for inch in my experience.

    I can get my wheel specs for you if you like. Let me know.

  12. #12
    Join Date
    Sep 2008
    Location
    N. Idaho
    Posts
    1,029
    I use crowned wheels and hollow grind free-hand as described by Joel M. from TFWW in a FWW article a while back (and is probably on YT somewhere). I have the 'slow speed' 8" grinder with white wheels that woodcraft sold ~10 years ago. Mark the back with a sharpie and check with a square as you go.

    Takes some practice to go freehand, but opens up other possibilities, i.e., adding a camber without stress. I just bought the same LV rest as an upgrade but didn't bother to get the jig.

    That's my $0.02-good luck and you'll get there!
    "You can observe a lot just by watching."
    --Yogi Berra

  13. #13
    Join Date
    Feb 2004
    Location
    Perth, Australia
    Posts
    7,362
    There is often some confusion with how wheel faces should be prepared.

    Joel Moskowitz (from Tools for Working Wood) wrote an influential article for FWW magazine over a decade ago. In this he advocated using a crowned wheel for the white and blue bench grinder wheels. The crown created a smaller area on the wheel, and made for more control in directing where the hollow grind work was done. I used this method for a number of years, and it works well. It is relevant to note that it is only designed to be used when freehand grinding.

    Some choose to leave the wheel face flat. This works fine as well, but it is preferred then (in my opinion) that the wheel is wide, since one can then push the bevel into the wheel, rather than run the blade across the face, as in the previous method.

    Then there is the Tormek, which is another grinder, albeit wet and slow. The reason advantage of the Tormek is the blade holder and guide. This runs across the wheel and creates an even and repeatable hollow. It is important for these wheels to be flat and parallel with the guide. When I discovered CBN wheels some years ago, I allied the Tormek BGM-100 guide to the flat CBN wheel for what I consider to be a simple and highly effective hollow grinding set up. The advantage of CBN is no wear and no maintenance, which is a major issue with the white wheels.

    Regards from Perth

    Derek

  14. #14
    Join Date
    Apr 2015
    Location
    New England area
    Posts
    293
    Quote Originally Posted by Tim Best View Post
    If I had the option of a subtitle for this thread, it would definitely be:

    "If not for the free time in my schedule and the free shipping offered by Lee Valley, none of this would be happening."

    Hi all. Like many, I have found myself with a little extra time on my hands lately, which has led to a re-evaluation of how I sharpen my plane irons and chisels. I took the hand tool plunge because I like my fingers attached and I really enjoy the sweet serenity of silence. After ogling over some of the images of precision hollow ground chisels and plane irons on the Creek and elsewhere and looking for a slightly faster way to grind and/or change primary bevels, and improve my freehand sharpening, I decided to dust off my much neglected 6" variable speed Delta bench grinder and invest in a tool rest and jig from Lee Valley. The grinder wheels are stock wheels, but spin true. Much to my surprise, the old grinder has almost no run out! Off to a good start!

    I installed the tool rest according to the instructions with the tool rest 2 inches from the base of grinder and square to the grinding wheel. I set the angle I was shooting for by using the included angle setting thingamajig and double checked its accuracy with a protractor. (I am so glad I paid attention that one day all those years ago in geometry class!) Installation was straight forward, but that is where my joy ended. Attached are my three test attempts on some cheap chisels of varying sizes. Something is amiss.

    For starters, it took a long time. I think I could have reground the primary bevel faster on coarse sandpaper. I properly dressed the wheel prior to starting so I do not think it was a case of wheel glazing, but not certain. The perplexing thing, one of them anyway, was my inability to grind a complete hollow. I managed to get close with chisel three, but I just could not get a full regrind. Also, has anyone else had issues with the jig not grinding square? The tool rest is square to grinder and the chisel is placed in the jig firmly against the alignment pin.

    I know there are several older threads that deal with this particular tool rest and jig, but I thought I would ask for thoughts, let everyone "admire" my handiwork, and hopefully get some pointers on how to properly use the tool rest and jig.
    Chuckles on me tonight! Thanks. chisel 1.jpgchisel 2.jpgchisel 3.jpg

    1. If you're changing the angle, regrinds can take a little extra time;
    2. Unless the edge is chipped, the grinder is there only to produce a hollow; you don't grind to the edge even when changing angles. Get close, and let the stones do the rest;
    3. All you really need a tool rest to be is a pivot point for the tool being ground, it usually doesn't require an elaborate after-market tool rest to accomplish this simple feat;
    4. If you think you need angular accuracy to within one degree, you're missing the entire point and your overall woodworking life is probably going to be hell.

  15. #15
    Join Date
    Dec 2010
    Location
    South Coastal Massachusetts
    Posts
    5,741
    I use a single, convex bevel - there's no settings at all.

    While it arguably uses more steel, and offers less precision - the method simplifies the process.

    No power grinding required.

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