ok quite new to this and using the machine primarily for carving knives. in reading the forum i see the reference to the ken jig which seems like a good idea and i believe the article mentions a wheel measurement of 250 mm but my understanding is that the wheel that comes with the t 4 is sg 200 which is 200 mm i believe so I can't use the measurements listed in the kenjig article and have to recalculate I guess.?? this forum is so extensive i would like to think that similar measurements are available for the 200 mm wheel if my thinking is correct. I hope this makes some sense sorry to be such a neophyte