Hi Hans

I think it is just a case of a slightly softer spot in the stone, we had
a large grinding stone outside the shop (3'x8" approx.) it had a dip in
it, since it was such a large stone and hand cranked it was not to bad
to use, I later fit a large pulley and a small motor on it, so that you
didn't need two people to do some wet grinding, also made the wheel
round again, the case here is that the low spot never sat in the water,
but to one side, the crank handle always hung down.
I think if you true up the stone you should be fine, it's part of the
upkeep and also keeps the stone open and working better

Have fun and take care
Leo Van Der Loo

Hans wrote:

I have used 2 wet grinders, with 3 different stones, sand stone, white
alu., pink alu,.

Before use I trued every stone, but after some time they all developed
some vertical movement.
A friend tells me all wet grinders do this unless you run them
continuously.

I think of buying a Tormek system, but would like to be sure it will
behave better.

Does anyone know what causes the movement?
Is it deformation of the stone?
Wears the thoroughly soaked part of the stone faster (or slower)?

What is the experience with Tormek systems?

Thanks,
Hans