Made this out of spare lumber materials lying around. An oak board and some hard rubber sheets. It's been working really well. You can rotate it 90 degrees in the vise and it easily holds a knife in the spine up position. Probably don't have more than $5 in it. I think the trick is using some good rubber. This rubber is very firm and grippy. It doesn't take a lot of clamping pressure to hold a knife firmly. BTW, if you loosen the bolt at the end, you can slip the knife in handle first and work on the blade as well.