My engine boring bar has a speed of 344rpm and a feed of 1-3/4" min. I have been using the inserts engine rebuilding supply shops sell which are generic to the many boring bar feeds and speeds out there as these inserts these places sell are all the same. The issue with using these inserts and my bar specs is they act more like a threading insert and not providing enough overlap ( currently 60 degree) which leaves very fine ridges through the cylinder. I was thinking a insert with a larger radius is what I need so I got on MSC to look at what they had and with so many inserts available I am a bit lost on what ones I should try. I believe the inserts I currently have are TPGH style. Any help getting me pointed in the right direction of recommend inserts would be great.