When grinding high strength concrete we are noticing the end of the cylinders to be bowed out and have tried slowing down the feed speed, also adjusted the shims on the slide base. Do you have any ideas on the cause as the ends of the cylinders should be true prior to breaking?
Most of the causes of this outcome are from the following reasons
1) using a non Marui design profile grinding disc
2) High strength concrete over time will radius the lead edge of the disk this will result in the cylinder no 1 & 3 having a lip on the outer edge.
3) The clamping station plastic block with rubber backing is worn and not holding cylinder level
4) The Vee nest fixture can also wear over time resulting in the cylinder not seating level.
5) Grinding disc not stopping in dead centre position on completion of cycle
Although some of these points will not give you the same outcome you should be aware of them for future.
If you could provide a photo of the problem we can give more direct advise on the grinding issue email firstname.lastname@example.org