I've got a set of them in a wooden box GB, have used them for stuff other than engine or fast moving bits, I now what you mean by judder, but my concern is/was I could not work out in my head if they reamed parallel or slight taper, has to be parallel of course but you know if you sow a seed of doubt it grows, I satisfied myself by reaming from each side - ah what happened to the unbound confidence of youth