Hey guys, very interested in bringing this old topic back up. We have been fighting this issue for years and have yet to find a good solution. A little explanation; Our application is for seal rings in multi-speed transmissions. Grooves are similar to an o-ring groove, but in some cases very narrow (i.e. the one we're working on right now is only 0.08" wide x0.12" deep on a 1.50" dia shaft). These are special seal rings made out of high end polymers (i.e. vespel, etc) which run at very high PV factors and having grooves cut very square to the shaft axis and a target finish of 8 is required or the life of the ring suffers. Parts are not going into space, but we have test data substantiating the requirement for these fine finishes. Not a high volume production, single digit to 10's of parts in an order. We've been trying to assist our machining vendors with developing processes and tooling to reliably cut these grooves without much success. Any guidance would be appreciated. Thanks