Quote from: tgbto on Today at 04:37:45 PMI don't believe the second knife (the one with the black handle) has been suddenly "eaten" by your T8. It has seen a lot of sharpening time before it went to a standard convex (or straight) shape to this concave shape.
The first one I can believe, and is a common problem with Tormek machines. It can be avoided with :
- careful technique (compensating by spending longer at the heel, not using too much pressure, ...)
- a few tips. Notably, the biggest improvement for me was rounding out the shoulders of the wheel after truing it. Too sharp corners will dig into the blade whenever the blade does not rest fully flat against the stone. Also, I always make sure to lay down the knife ever so slightly tilted so the heel hits the stone first and not the other way around. Of course you have to aim for flat, but better to err on the heel-first side rather than heel-last.
As for your wobble, is your video taken right after truing ? That would be odd. My bet would be that the stone has been trued, taken off, then put back on, but rotated. There has to be some clearance for the wheel to slide onto the shaft. So if you put it back in a position that's different from the one used for truing, then that will create some wobble (proportional to 1-cos(alpha_truing-alpha_sharpening) ). Standard practice is to always put the stone on the shaft "label up".
Also, please keep in mind that such wobble is unstable. Said otherwise : it will create a more uneven surface over time, especially if you use heavy pressure : the blade will kind of dig in each time it encounters a low spot, making it even lower. This is another reason to use reasonable pressure, and to often true the wheel a little as opposed to seldom true it a lot. However, if every part of the blade sees the wheel a similar amount of time, the effect of this wobble will be homogeneous along the length of the blade and will not create dishing.
Hope this helps!
Hello!
Yes, the video is taken seconds after I once again tried to get the stone level.
As for placement of the stone, I always orient it with the label facing upwards.
I see the wobbling on the honing wheel also, so I suspect the shaft itself is no longer straight or something inside the machine is causing it to jump up and down, because one of my plants on the table where the Tormek is placed seems to be swaying rhythmically to the machine as well.
BTW, I have the T4, not the T8.