Choosing a default angle

[John Hancock Sr]

the KS-123 has significant hysteresis

I have not noticed any.

[tgbto]

the KS-123 has significant hysteresis

I have not noticed any.

Do you mean that says, one 8th of a turn on the MicroAdjust always results in the plastic needle moving on the KS-123 ? On mine, even after some lubrication, if I move the USB down, then up, I can change the angle by almost 3/4th of a degree before the needle starts moving up again. And I can move the needle up and down by hand, the flexibility and friction will let it stay wherever I put it within one degree.

[Ken S]

I learned a new word, "hysteresis". I have known about the effect of "thread slop" on adjusting screws for many years. I first encountered this with the depth adjusting screw of bench planes. For accurate measurement, the final step should be a slight tightening of the screw to leave some load on the threads. This situation occurs even with the adjustment wheels of high quality machinery such as metal lathes. Experienced machinists make this adjustment automatically.

The Tormek online classes mention this in passing, although they have never explained why this happens. The compensation necessity is not caused by the KS-123. It is caused by the threads of the microadjust. It is not a design defect with the microadjust; it is just the nature of the beast with adjustment screws. And, on a practical basis, it is not really a problem with Tormek sharpening, especially with good technique. Use the microadjust by lowering only for rough adjusting. Make the final, more precise adjustment only by raising it.

Ken

[Rossy66]

I learned a new word, "hysteresis". I have known about the effect of "thread slop" on adjusting screws for many years. I first encountered this with the depth adjusting screw of bench planes. For accurate measurement, the final step should be a slight tightening of the screw to leave some load on the threads. This situation occurs even with the adjustment wheels of high quality machinery such as metal lathes. Experienced machinists make this adjustment automatically.

The Tormek online classes mention this in passing, although they have never explained why this happens. The compensation necessity is not caused by the KS-123. It is caused by the threads of the microadjust. It is not a design defect with the microadjust; it is just the nature of the beast with adjustment screws. And, on a practical basis, it is not really a problem with Tormek sharpening, especially with good technique. Use the microadjust by lowering only for rough adjusting. Make the final, more precise adjustment only by raising it.

Ken

I have noticed this the more I use my T8, I have gotten into the habit of making my final adjustment when raising the universal support.

[Ken S]

To borrow a phrase from Wolfgang, making your custom of making the final adjustment by raising the microadjust will serve you well. In itself, it may not be a big deal; however, small improvements compound.

Ken

[John Hancock Sr]

To borrow a phrase from Wolfgang, making your custom of making the final adjustment by raising the microadjust will serve you well. In itself, it may not be a big deal; however, small improvements compound.

Ken

Probably why I don't notice it. I allow for the slop in the mechanism, always have done. Force of habit.

[tgbto]

There are two phenomena with hysteresis here :

- One linked to the threaded rods, which can be compensated by always ending with slightly raising the USB. This is standard operation and does not cause any issue. It will prevent the USB from settling lower due to the rod moving slightly insided the nut before getting fastened.

- Another one linked to friction inside the KS-123. Going down, then up, will ensure that the error is always on the same side. For a given static friction coefficient, that is, which will depend on when it was lubricated, if it is slightly wet or not, how tight the nut is, etc. Plus, the amplitude of USB movement necessary to put the needle back in motion on the way up is much, much higher than with vernier calipers resting against the top of the USB and the wheel where only the slightest turn of MicroAdjust nut is enought to lift the lower end of the wheel.

So while using the down-then-up routine will minimize the error, it will still be more important than using the distance method, less reproducible, and therefore the amount of material that needs to be removed before raising a burr will statistically increase.

[RichColvin]

When I hear concerns about using the KS-123 due to it being less than needed accuracy, I wonder why the angle on the blade must be accurate to 0.1°.  In the sharpening I do for most things, if the angle is good to +/- 1 degree I am good.  What am I missing?

[John_B]

When I hear concerns about using the KS-123 due to it being less than needed accuracy, I wonder why the angle on the blade must be accurate to 0.1°.  In the sharpening I do for most things, if the angle is good to +/- 1 degree I am good.  What am I missing?

Nothing.

I think this is an example of going to the extreme without any clear delineation of the benifit. When Wootz proposed some new idea he backed it up with extensive testing and real world usage in meat packing plants. I believe only a miniscule number of users have the ability to measure the angle to this accuracy.