Tormek stone grader

[johnmcg]

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...

[Jan]

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

[John_B]

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.

[johnmcg]

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!