endless frustration (out of square grinding)

[stwing]

I'm sure this question has been asked and answered countless times - I've ready many of those posts - but for some reason I just can't get it right. I have a supergrind 2000 and no matter what I do, it will not sharpen plane blades or chisels square. They're not a little out of square either - they're terribly out of square. I've used the diamond tool to cut the stone, adjusted the pressure on the square tool jig, purchased the newest version of the square tool jig - everything I can remember reading on this forum I've tried yet my Tormek will not grind a tool that I can use. It's endlessly frustrating.

What am I missing? It seems like there must be something I'm not doing or seeing that could be causing the problem to be so pronounced. (A 1 1/2" plane blade will be 1/32" out of square - it's that bad).

Thoughts? Suggestions?

Thanks for any input.

[Jeff Farris]

I'm afraid there are likely several issues at play here, rather than one. So let's address them one at a time.

First, with regards to plane irons, any tool that is near the width of the grindstone or greater is going to be more difficult to keep square than a tool that can be traversed across the grindstone without any portion of the blade leaving the stone. When a section of the blade leaves the grindstone, but other parts remain on the grindstone, an uneven cut is occurring. It is up to the operator to make sure that the time spent on each section of the blade is correct to deliver a square grind. The only way to do this is to have a square handy by the grinder and use it frequently while grinding. If one side or the other is long, concentrate your grinding on the long side for a few seconds to bring it back into alignment with the rest. The reason for the uneven grind is most likely completely unconscious. Either you're taking less time on the long point or you're using less pressure. It really doesn't matter what's causing it, just correct it by frequently checking with a square and correcting the grind.

Similarly, the straightness of the edge is controlled by the operator and can only be maintained accurately by checking and adjusting. The part of the blade that is off the stone is not being cut. This is particularly evident when a short stroke is used, which results in a concave grind. The two outside edges leave the grindstone, but the center never does, so the iron will be overground in the center and underground on the edges. You have to take the left side of the iron all the way to the right side of the stone and vice versa. A slightly convex edge can be created by spending just a bit longer on those outside edges.

As for chisels with the SVH-60, please see the PDF linked here:  http://www.sharptoolsusa.com/squareedgeweb.pdf

In a nutshell, the pressure on the clamping bar will roll the tool minutely to the right or left, resulting in an out of square grind. This can be corrected once found by reducing the pressure on the short side and increasing the pressure on the long side.

The SE-76 is a little trickier. The paragraph above with regard to plane irons applies equally to the SE-76 and SVH-60.  The SE-76 won't automatically produce a square edge on tools that leave the grindstone while working their width. For tools one inch and under, it should be delivering a square edge, if the Universal Support is parallel to the grindstone and the tool is flat from the back to the front. One thing I've noticed that you can watch for...I notice that the blade has a tendency to squirm away from the index as the clamp is tightened. Make sure that the tool is correctly aligned as the clamp draws secure.

Try all this and let us know how it goes.

[stwing]

Jeff-
thanks for the detailed reply - you have the patience of Job to deal with this same question over and over again.

I was sharpening a small blade (for a Lie-Nielseon 102 block plane) which could be sharpened without having to ever leave the stone. However, out of habit, I do extend past the left and right edge of the stone as I sharpen (that's a necessity for many plane blades).

I seemed to think this used to be easier when I first started using the Tormek, but perhaps it's just that my tools are better tuned now and my expectations are higher so any issues are magnified.

Regardless, I will follow your suggestions and report back with feedback I hope is valuable to others who deal with the same issue.

Thanks again for your prompt, thorough reply.
Shawn.

[Jeff Farris]

... but perhaps it's just that my tools are better tuned now and my expectations are higher so any issues are magnified....

I know I'm guilty of this. I get pickier and pickier as I progress...not just in sharpening and woodworking, but in many pursuits and passions. Also, it's a lot easier to be picky when sharpening the iron from a $250 plane than it is for a flea market beater. 

[ionut]

Hi,

In addition to what Jeff has said, in my experience with my machine I didn't get large our of square edges for larger blades than the stone, it was usually visible but pretty small and easy to correct by checking frequently as Jeff explained and try to control your moves. There may be something wrong with the  trueness of the stone compared with the universal support or the way the blade is clamped in the jig. So I put together few more points that you may want to check.

-   The assumption is that your stone is true and the universal support is parallel with the stone.
-   If the blade is not larger than the stone you do not have to take it out of the stone more than 1/8 of an inch.
-   If it is larger treat the corners of the blade as you treat high spots when planning the wood. I usually count two passes on the corner still leaving ¼-1/2" of the blade on the stone for each pass of the center. Also try to keep the pressure constant on the blad I know I have the tendency to be harder with my right side.
-   When you true the stone and adjust the universal support for all the operation, before locking the knobs apply medium pressure with one finger over the adjusting post of the universal support, or you back up the adjustment well a quarter and bring it back exactly like the backslash in the case of the blades. Some machines allow for more or less play of the universal support so if you apply pressure on the extremities you may start out of square from the beginning.
-   If you grade your stone you can try using the grader along with the stone and not across it. Hold one end with one hand and with the other end press the grader on the stone moving it sideways just a little enough to cover the stone. I managed before  to take the stone out of square just from grading using the grader across the stone. In the way I presented it it is less likely to apply more pressure with on one side only.
-   .regardless the straight jig you have you may try to clamp the blade in the center and not at the index and apply uniform pressure on both knobs while tightening that will ensure that the tool will not slide in the clamp. To verify for square use a small square, before completely tightening the knobs.
-   Don't assume the stone is flat, square and parallel with the universal support, check it. I check that almost every time before sharpening a tool, it takes few seconds, and true it if needed. As soon as you start sharpening the stone wears and the steel gets grinded and depending on the tool and how you sharpen the stone may get untrue, so make sure everything is right.

Since I followed these steps I stopped having out of square edges. I hope that helps.

Ionut

[ionut]

There is one other thing that will affect the square of the edge. If flattening the back was not done properly and the place where the blade is clamped is not in the same plane with the cutting edge, you will never get a square edge, usually you will see a consistent angle (not 90) after each sharpening on the same side of the tool.

Ionut

[Ern]

It's also worth checking to see if the sides of the chisel or plane iron are parallel.

[Ken S]

One of my photography instructors had a favorite saying (from a Chinese fortune cookie); "When you are in a hurry, dress slowly".

We have probably all heard the story of the high school wood shop teacher who made his students endure countless hours handplaning a board until it was perfectly square and parallel.  It is tempting upon opening a new Tormek to gather all the chisels, plane blades, etc. for a long awaited sharpening.

The idea of spending much of an initial sharpening session concentrating on one blade painstakingly checking it with a Starrett square probably doesn't sound very exciting.

Shawn, I think you are wise to want to get your block plane blade dead on.  By the way, how did it go?

Ken