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How Do You Hollow Grind

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Forum topic by davidroberts posted 05-03-2009 05:11 AM 5809 views 0 times favorited 11 replies Add to Favorites Watch
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davidroberts

1025 posts in 2949 days


05-03-2009 05:11 AM

Topic tags/keywords: question sharpening

I need some advice on how to hollow grind. Do you use a white wheel and if so, what grit. I’ve read where 120 grit is to fine. I have an old craftsman 6 inch grinder. It’s a high RPM model. Can a white wheel be used effectively on a high RPM grinder? Also, do you use a buffing wheel, and if so, do you use a polishing paste on it? And lastly, do you use a leather strop or leather wheel. Sorry for all the questions. It’s cheaper than returns! Thanks.

-- Better woodworking through old hand tools.


11 replies so far

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TopamaxSurvivor

17669 posts in 3139 days


#1 posted 05-03-2009 06:07 AM

I don’t know anything about white wheels. I use my old craftsman grinder to sharpen everything from lawn mower blades to drill bits & chisels. I have a course wheel and a fine one, don’t remember the grits off the top of my head. Using high speed, you need to watch out for burning the steel. If it’s blue, it’s burned! Keep dipping in water to keep it cool. I use a strop. Not sure I have ever heard of a leather wheel??

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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DaleM

952 posts in 2847 days


#2 posted 05-03-2009 07:26 AM

Okay, first, I apologize for the long reply because there is no one right answer, plus I just like to talk/type. I don’t hollow grind anymore, but I used to. I would just use the finer of the two stock wheels, both gray, that came on my craftsman grinder, just a little grinding, then dip the tip in water frequently, and go right back to the wheel. Then, I would take the chisel to my oilstone for final sharpening. I only used the grinder when my chisel was in very bad shape. As for the leather strop, I still use that, just to run the blade across a few times but no leather wheel. I did use the jeweler’s rouge on the leather strop, but quit and saw no real difference. The leather is only to take the fine “burr” off the edge anyway. Lately, to be honest, I mostly just use the “scary sharp” method, which involves using increasingly finer grits of sandpaper but I am planning on going back to a wheel and stones due to the constant use of sandpaper. I really don’t see a benefit to a hollow grind, but just know that if you use a rounded wheel, you do get a hollow grind, and the smaller the wheel, the deeper the hollow. I do know you can use a white wheel on a regular high speed grinder, but it will still overheat the blade if you are not careful. Just use it for a couple seconds at a time at most and dip the blade tip in water in between and you should be fine. As for a buffing wheel, my experience with them is they actually dull the edge, as they slightly round over the edge. I would go straight from the wheel to some very fine sandpaper or a very fine oilstone or wetstone, then strop it a few times on plain leather. Wow, this is hard to talk about on here, as there are so many ways to do this, although my wrist and the back of my hand has been mostly bald for years from testing my edges for sharpness throughout several methods, so there is apparently more than just one way to do this so I’ll be following this post myself for better ways to sharpen.

-- Dale Manning, Carthage, NY

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JimmyC

106 posts in 2865 days


#3 posted 05-03-2009 07:41 AM

If you can grind on a high speed standard (fine) wheel and get the angle without overheating the metal (causes loss of hardness) then by all means do it. Slow grinders and ‘white wheels’ slow everything down and make it easier and safer (as far as losing hardness) for most people. After grinding, get a wheeled jig and create a microbevel on your your chisels, or blades, using either a med or fine stone or a piece of 220 grit wet/dry sandpaper. Set the jig to hold the blade in a position that causes both the front and back edge of the hollow grind to make contact and give it enough strokes to creat the mico bevel. You should be able to do this a few times before you have to grind again. Your chisel and plane blades will be as sharp as you will possibly need.

If you have the money, buy a worksharp 3000 it does a great job quickly, but a t a cost.

Good Luck.

-- -JimmyC...Clayton,NC- "Just smile and wave boys, smile and wave"

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DaleM

952 posts in 2847 days


#4 posted 05-03-2009 07:55 AM

Here is a link to a fellow LJ’s method of sharpening that involves both a wheel and a stone.
There are other posts if you use the search feature at the top of the page, but they all essentially show you the same thing. The one thing to focus on in this particular link is the way he uses the hollow grind to rock the bevel back and forth to get the right feel for the angle to sharpen the blade on the stone. Just get the back edge and front edge of the bevel to lay flat on the stone (or fine sandpaper) and you’ll be fine. http://lumberjocks.com/kolwdwrkr/blog/7515

-- Dale Manning, Carthage, NY

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TopamaxSurvivor

17669 posts in 3139 days


#5 posted 05-03-2009 08:59 AM

What are white wheels JimmyC? Made for slower speed grinders? They can’t be used on regular hi-speed grinders?

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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marcb

768 posts in 3137 days


#6 posted 05-03-2009 02:52 PM

http://lumberjocks.com/marcb/blog/8311 Heres how I do it. Try to use the coarse side, the fine side heats things up a lot faster.

This is on a standard speed grinder.

A white wheel can help you not overheat the metal, but I don’t really have a huge issue without it. just quench in water.

Since I did that blog (1st grind ever) I’ve reground just about everything. I also picked up a DVD from Norton Abbrasives on free hand honing. The guy doing the video owns the store Tools For Working Wood.

I was able to free hand hone razor edges after viewing that video, nice and simple. I had played around with free hand sharpening, but didn’t get as good of results.

Topamax, white wheels are more friable. They disintegrate faster/grind slower, thus keeping the heat down

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JimmyC

106 posts in 2865 days


#7 posted 05-03-2009 04:40 PM

Topomax, Everything said above about them and yes they go on regular speed grinders. The wheels can come in white, pink, or blue and just work much better for fine tools. I have a 6’ grinder with standard coarse and rough wheels for general sharpening, one with two white wheels , and a third 6” with a wire wheel and buffing wheel, the standard wheels and wire wheel seem to to be used most often ( but not for chisels and plane blades :>)). Here’s a site for you to check the wheels out :

http://www.woodcraft.com/family.aspx?FamilyID=216

Good Luck.

-- -JimmyC...Clayton,NC- "Just smile and wave boys, smile and wave"

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a1Jim

115202 posts in 3040 days


#8 posted 05-03-2009 08:33 PM

although you might have a hard time sharpening a lawn more blade on it My vote is for one of the Work sharps
I have the 3000 and it works great before that I used the scary sharp method by Mike Dunbar it worked great too but slower.

-- http://artisticwoodstudio.com Custom furniture

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marcb

768 posts in 3137 days


#9 posted 05-03-2009 08:44 PM

I highly recommend pulling out the grinder and just giving it a go. Theres really no reason to spend lots of money on trick sharpeners if your a hobby wood worker.

Free hand grinding and honing is a skill that takes a little practice to get down, but its not so difficult as to be impossible for the beginner. You don’t need to grind perfectly square across the face, just get everything close and the honing will even it out.

A cheap grinder with a coarse wheel, a dixey cup to quench and a simple set of oil stones will get you a razor sharp edge with minimal practice.

And save you enough money that you can afford some good teak for your next project.

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TopamaxSurvivor

17669 posts in 3139 days


#10 posted 05-03-2009 10:43 PM

Thanks for the wheel color explaination guys. I just sharpen my “construction” grade chisels on the fine grinder, the same one I use for drill bits. I have always been a hand sharpener when it comes to the better blades.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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davidroberts

1025 posts in 2949 days


#11 posted 05-04-2009 04:20 AM

Thanks all. I’m going to purchase the LV VeritasĀ® Basic Grinding Set

http://www.leevalley.com/wood/page.aspx?c=2&p=32975&cat=1,43072,45938

and pick up a Norton white wheel, 80 grit, on the bay. I have several waterstones of various grits, which I have used for quite a while. I like the concept of the hollow grind method. I like the the idea that you can rock the edge of the blade to find the flat spot. I don’t like using a honing guide, which I’ve used the $12 wheel type for a while also. I can never seem to get the angle perfect each time. Not that it has to be perfect. I just like to get close.

-- Better woodworking through old hand tools.

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