I believe using the stone grader is an underexplored part of Tormek technique. The stone grader and stone grading offer more potential benefit than most users realize, or that is included in the handbook.
I believe the concept of the stone grader for the Tormek grinding wheel began when Tormek changed from the original natural grindstones mined locally to manmade aluminum oxide grinding wheels, the present SG (SuperGrind) grinding wheels. The SG wheels cut more aggressively, but do not leave as fine a finish. Tormek's clever solution to this dilemma was the stone grader. The SG could be left in its natural 220 grit state or be graded to a finer 1000 grit. This allowed the one grinding wheel to do double duty, a real innovation.
The stone grader can do more than just coarse and fine. I prefer coarse and fine to grit numbers. I have no way to test for exact grit numbers, and believe there is variation. No matter; the stone can cut either coarse or fine. It can also cut with at least middle grit, often called "600". This middle grit is a favorite among some Tormek users, although its existence is often unknown outside of Tormek.
I have absolutely no factual basis, however, I would not be surprised if this "600" middle grit was influential in Tormek choosing a 600 grit diamond wheel as the standard wheel for the knife specific T2.
I believe many of the uneven wearing problems associated with the stone grader may actually be caused by poor technique. Watch Stig using the stone grader in his video with Stumpy Nubs. Stig makes it look easy, however, his stone grader technique is very polished. He presents the middle of the long side of the stone grader to the wheel. He is keeps his hands resting on the support bar and the stone grader parallel to the support bar and the edge of the grinding wheel. I suspect most of us, myself included, have not always been that careful.
I am planning two related topics about stone grading. This topic will cover using the Tormek stone grader. The second topic, coming very soon, will cover non Tormek methods of stone grading. For ease of reading, please post replies in the appropriate topic. (Thanks in advance.)
Ken
Quote from: Ken S on July 13, 2018, 04:36:12 AM
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Watch Stig using the stone grader in his video with Stumpy Nubs. Stig makes it look easy, however, his stone grader technique is very polished. He presents the middle of the long side of the stone grader to the wheel. He is keeps his hands resting on the support bar and the stone grader parallel to the support bar and the edge of the grinding wheel. I suspect most of us, myself included, have not always been that careful.
...
https://youtu.be/ESW3wy0PI18?t=11m40s
&
https://youtu.be/cSUT0k0Vd-Y?t=2m48s
;)
Good post, CB.
Ken
Ken,
I've stopped using my stone grader long ago. I've found out the stone get clogged by the steel of the blade and gets smooth after a few seconds. Spending the time to change the stone grade just to be able to take of more steel takes more time then just sharpening one or 2 passes extra.
Although using the fine side could sometimes make the stone smoother then it is when not using it at all. I don't know how much tough. Never really measured.
I wonder how many use the stone grader and how often?
What is others experience?
Quote from: WolfY on July 14, 2018, 10:25:08 AM
Ken,
I've stopped using my stone grader long ago. I've found out the stone get clogged by the steel of the blade and gets smooth after a few seconds. Spending the time to change the stone grade just to be able to take of more steel takes more time then just sharpening one or 2 passes extra.
Although using the fine side could sometimes make the stone smoother then it is when not using it at all. I don't know how much tough. Never really measured.
I wonder how many use the stone grader and how often?
What is others experience?
For years, I pretty much left the stone in its "natural state"... never using the Stone Grader. But with all of Ken's nagging (haha)... I've started using it more on my personal knives for "maintenance sharpening"... keeping it graded "fine"... I do find the results are better... it is a noticeable difference. (I agree with Ken... until you figure out how to use it... it doesn't seem to make a difference, but once you do, you see it).
But, if I'm doing a batch of knives for someone, I go back to "natural"... more than "good enough". ;) (So, basically saying, depends on the circumstances).
WolfY,
I have a tendency to resist writing something off as not working well until I am certain that I have mastered it. It took a while, but I finally feel that I have mastered the TT-50 truing tool. I like it.
For me, the jury is still out on the SB-250, and to a lesser extent on the stone grader and the leather honing wheel. When people whose sharpening skill I respect speak well about a product or technique, I think I need to keep learning. My gut feeling is that I have not yet mastered the stone grader. I am hoping replies will offer helpful suggestions.
I believe Tormek users will be in two groups in the future. The first group will continue to use the original Tormek SG wheel. The stone grader, or at least stone grading, will continue to be important. The second group will invest in diamond stones and have little or no use for stone grading.
Like you, I will be interested in reading the replies.
CB,
Your system seems logical, depending on your batch sharpening prices. If your batch techniques represent good value for the prices charged, that seems fair to me. I would expect to pay more for a sharpening done precisely to a low BESS number.
That stated, I believe the innovations acquired from very high end sharpening can elevate the general standard of work.
Ken
to answer Wolfy questions: I wonder how many use the stone grader and how often?
What is others experience?
I started using the stone grader when I bought the T-8 about 5 months ago. I learned by watching Stig and Jeff Farris. they both do a great job teaching. that leaves "experience". I started using and refining their techniques and now use it every time I need to cleanup or re-grade the SG-250. The Tormek grader has served me well and still looks almost new due to following Stig and Jeff techniques and advice.
As far as my SJ-250, I usually clean after use with the rust erasers, which do a fine job. I didn't think the SJ-250 actually needed grading, but after watching Wootz video's, I decided to use the diamond plate approach. With the help of Ken and a little luck, I put together a great way to grade the SJ-250 with the diamond plate.
IMO, it is very important to use the stone grader's of either or both methods to improve your stones and your level of sharpness !
Very good post, Grizz. You have put in both the study time and focused sharpening time to master the Tormek stone grader. From that position of skill, you are able to intelligently investigate other methods. I think you have an ideal approach.
Keep up the good work.
Ken
I'm not sure if this topic is being followed still but...
I've always used the stone grader and found it works great - allows some serious metal removal at the coarse end when (occasionally) needed and provides a reasonable finish at the fine end. Now I just use my Japanese stone for repeat honing (chisels and plane blades) as the quickest and easiest solution, until the blade needs a new bevel ground, (or has been damaged!). I have two questions though for those more experienced...
1. Over time the fine side of my stone grader has become dished - is it still useable or should I replace it? (I'm concerned it might change the shape of the wheel, although I haven't been able to ascertain the veracity of this.)
2. I've read two opposing views: that the stone grader should NOT be used on the Japanese stone, and that it CAN be used on the Japanese to remove the inevitable black marks/glazing. Any opinions on this would be appreciated (if no, what do people do to occasionally clean up the black marks.
Cheers...John
Quote from: johnmcg on July 12, 2019, 03:06:04 AM
Over time the fine side of my stone grader has become dished - is it still useable or should I replace it? (I'm concerned it might change the shape of the wheel, although I haven't been able to ascertain the veracity of this.)
You control the shape of the grindstone with the truing tool. The fine side of the stone grader will conform to this shape. Jeff Farris used to tell us that having the fine side concave makes it work better. I agree.
Quote from: WolfY on July 14, 2018, 10:25:08 AM
I've found out the stone get clogged by the steel of the blade and gets smooth after a few seconds.
If enough of that swarf gets embedded in the grindstone then grinding becomes very inefficient. I apply the coarse side of the stone grader, often using the edges, to remove the swarf. Then I spend a few minutes applying the fine side of the stone grader, if a finer grind is desired.
Quote from: Ken S on July 15, 2018, 02:01:32 AM
I believe Tormek users will be in two groups in the future. The first group will continue to use the original Tormek SG wheel. The stone grader, or at least stone grading, will continue to be important. The second group will invest in diamond stones and have little or no use for stone grading.
Perhaps it will become cost effective for many of us to have one of each type. With each being used for one of its particular tasks, the two will last much longer and in the end save money.
Quote from: johnmcg on July 12, 2019, 03:06:04 AM
2. I've read two opposing views: that the stone grader should NOT be used on the Japanese stone, and that it CAN be used on the Japanese to remove the inevitable black marks/glazing. Any opinions on this would be appreciated (if no, what do people do to occasionally clean up the black marks.
Cheers...John
For the SJ stone, Tormek states that the fine side of the stone grader can be used. That was ok for me, but I prefer to use a Nagura stone. Ken lent me his, and it worked so well that I bought one. https://www.amazon.com/gp/product/B0037M4R7A/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Kind regards,
Rich
Thanks all for your replies - I will look into that Nagura stone Rich. BTW, does it matter what grit the Nagura is?
I have and used the Nagura stone for a while, until I was turned on to a similar but different product, called Sabitoru Rust Erasers (https://www.amazon.com/gp/product/B00FS0BFJC/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1). I'm aware of two grades, medium and fine. I bought the ones I have from Amazon, which is where the link above takes you.
They clean the SJ stone faster and better than the Nagura, IMHO. I'm not even sure where my Nagura stone is anymore.
Rick
Quote from: Herman Trivilino on July 12, 2019, 04:22:21 AM
You control the shape of the grindstone with the truing tool. The fine side of the stone grader will conform to this shape. Jeff Farris used to tell us that having the fine side concave makes it work better. I agree.
I've been thinking about this Herman and am not sure I agree (except in one specific instance - I do agree with this if the grader is dished evenly across it's whole length i.e. a constant "u" shaped concave dish in it that conforms to the shape of the grind wheel).
However, in moving my grader back and forth (sideways - as many Tormek videos show) across the grindstone my stone grader has developed a non uniform dish shape - the concave area is oval shaped in plain view i.e. the dished area does not extend fully to the ends and gradually tapers off. This means there is a concave shaped dish across the length of the stone as well as across the width - which, in turn, means there is a curved shape across the width of the grindstone which will be imparted to the grindstone over time. In fact, now that I am looking for it, I can see that my grindstones are not uniformly flat across the width and has a slight curve/camber to it. I think I am going to try to flatten the fine side of the stone grader with an old (read disposable!) diamond stone I have - I imagine it will be slow progress considering the hardness of the stone grader...
I've tried to add a pic to illustrate what I mean (hope it works!). The plan view shows the dished area (oval in shape). The end view shows what you are saying - the wheel conforms to the shape of the dish (or vice versa) - as long a the dished area extends far enough along the stone and is uniform. The side view shows the problem (I think!) - when the dished area doesn't extend the full length of the grader and tapers off, the dished shape will affect the "flatness" of the grindstone across its width (shown by the arrows).
Any comments would be appreciated...
John, I agree with you. The fine side of my Tormek stone grader is dished also and having this shape it cannot correctly grade the grindstone. Oval dished stone grader grades the edges of the stone, leaving the middle part untouched. If I need to grade the SG stone really fine, not compromising its trueness, I use an inexpensive diamond plate (1000 grit) mounted in the square edge jig.
In my opinion the grader should be replaced as soon as it is visible that it is irregularly dished.
I am going to make simple bracket, which mounted in the square edge jig, would guarantee that the grader approaches the grind stone always in the same way.
Recently I have bought dressing sticks designed for refreshing diamond and CBN wheels. The sticks are made of aluminium oxide and should be used for cleaning and opening of the superabrasive wheels. They are inexpensive.
The large (30x30x300 mm), dark dressing stick is for bench grinder. It is made of silicon carbide.
Jan
Jam I like the idea of the diamond plate. I find that I rarely need the coarse range offered by the SG wheel, however, grading it to the finest possible value would be a real benefit.
I have seen a real decrease in damaged knives since I began my education campaign. I am more of a concierge sharpener and I have a group of repeat customers. I do get some new word of mouth customers that I have to explain the care and feeding of a knife edge to.
Thanks Rick and Jan - all great ideas I will be trying out. And I thought buying a Tormek would be the end of my sharpening woes! :o