Review on Research FLEX HONE Cylinder Abrasive Diameter by Chris Bowden

I used this to crack the icing on a 68mm bore of a cast steel motorcycle engine cylinder. It worked very well - 10-30 SAE oil, 1500 rpm for a few minutes left very smooth honing lines. BUT 1: You REALLY need to take the time to get the grain out of the barrel after sharpening. and 2) I think you may need to run the devices longer than I did as the results were still evident after running in Bke.