Thank you Ian.
What has really helped me on satin finishes is to have a more gradual plunge line. Not sure what you call them, sweeping plunge line? When I tried to put satin finish on a sharp 90 degree cut plunge I could not get into the corners very well. Also, an abrupt plunge, in my opinion, makes it harder to drag straight scratch patterns across the blade. There are some great successful satin finishes out there with the hard plunge lines. But I found it very difficult. Bad technique or just not as skilled or maybe lack of patience perhaps? I was just never very happy with my results. But, when I changed to the gradual plunge I had a much easier time. Easier to clean up the plunge line area. Easier to get straight scratch pattern when riding the gradual ‘ramp’ plunge verses the ‘cliff’ plunge. Just using descriptive words. Not sure what the official wording is. Still takes time but I attribute an easier time to the seeping plunge. I go up to 600 on the belt grinder. Move to hand sanding after that point. I do go back to 400 as the first step on hand sanding because I always still have a few stray scratches the 600 belt grind didn’t get. I sand diagonally like I think most do. 400, 600, diagonal and then 800 straight. I stop at 800.
I do hollow grinds 95% of the time. I made a wood handle with a radius matching the wheel I use. Glued leather on the radius as the backing. I use a thick piece of G10 as backing for the flats.