It depends

but really it does depend on the axe profile, how much wear the bit has seen and so on. Let me just say I'm no axpert. I just do what works for me and I get there by trying different things. For my current production Vaughan I would say the bit is probably at .5 - 5/8 inchs at the center currently. It is what is refered to as a banana grind so that tappers down towards both the heal and toe. I simply thinned, sharpened, tested and repeated until I was happy. That was until I did the GB comparison and I realized that the bit thickness at the centerline on my Vaughan was about the same as the GB. That just wouldn't do so I decided to thin it a bit more since then. As part of that process I did actually lay the entire head on rag (in place of a mouse pad) backed sandpaper. This contacted the back of the bit and very top of the ramp at the same time. I figured this couldn't hurt at this point. I'm honestly not sure what the actual angle is because I've never measured it but I can try to get you some sort of idea if your interested. Once I get it back on a handle I'll see if my efforts made a noticeable difference. In the past I will say the work definitely paid off.