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I bought a T7 second hand (actually the wife picked it up at an auction for me) and the wheel was rusted solid on the stainless shaft. The wheel broke coming off. The shaft was also well worn. It looked like it had never been lubricated. In hindsight I could have taken it off with the correct technique but hindsight is marvellous.

I always remove the wheel after a sharpening session and have storage for all of the wheels to allow them to dry properly. I also keep the shaft well lubricated.

I have a draw knife which is similar in shape but longer. I don't bother with the machine, I sharpen it by hand. I hold the knife handle while drawing the stones along the blade.

John, do you measure the sharpening angle you achieve to compare it to the KS-123 setting?

No, but I do not get any hysteresis, which is the discussion I am commenting on. If I wind up a fraction the needle moves, if I wind down a fraction the needle moves.

I find that ensuring that all three pins are firmly on the wheel and the bar is held as indicated in the Tormek videos I can get the angle spot on.

Looks fantastic. Putting in an order with my local printer -- AKA my son!

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.

the KS-123 has significant hysteresis

I have not noticed any.

I am not a professional so take my advice as it comes. My approach is to select a default of 20. The reason is two fold. First, the majority of general purpose kitchen knives recommend that angle, and second it is a good angle for general purpose use whilst not making it too fragile. I would have thought that 18 would also be a good compromise. When I do use a smaller angle I advise the owner to reserve that knife for fine work et al to prevent damaging the knife. All of my sharpening is for home use by non professionals so I rarely use a smaller angle.

There is the Tormek plastic matt but a much cheaper option is one of those silicone dog or cat trays from Amazon or your local pet supplies. Just get one with similar dimensions as the Tormek.

With the prevalence of diamond and CBN the sharpening difficulty is not so relevant anymore

The intro is not quite correct. There have been many refinements over the years which is patently obvious but otherwise quite interesting.

That can be a life saver (figuratively of course) for larger holes on lower power drill presses where the burr on the underside of the material can catch and stall the machine. 

Still, from a physics standpoint, in a situation where a solid moves in relationship to another, the friction coefficient is the ratio of the tangential force to the normal force. If there is no friction, there is no tangential force applied to the material being cut, so no work being done and obviously no matter being removed.

The work being done can be measured by the material being removed (bonds being broken within the steel) and the generation of heat. You need to maximise the first and minimise the second. We want as little heat as possible and as much material removal as possible for maximum efficiency. This is achieved by ensuring that the relative MOHs hardness of the abrasive is higher than the steel, the abrasive keeps as sharp as possible (friability helps with this) and the surfaces slide past one another as smoothly as possible, which is done by lubrication. The lubricant also assists in removing any heat that may be generated by friction. Water and oil have both been traditionally used on sharpening stones.

Eventually found that my trusted ceramic stones just couldn't handle the harder steels, loads of work, glazing on the stones,

There are different ceramic compounds and they have differing harnesses. It really depends on the MOHs hardness of the ceramic in the stone.

Friction is nothing more than generating heat.

Indeed, the water actually acts as a lubricant as states by Tormek.