Honing guide measurements?

[AAvK]

Millimeters = equals degrees with the most basic vise type of guide, bought mine at a Rockler store. The instructions only give the following:

Chisel projection: 30mm = 30º / 40mm = 25º Plane iron projection: 38mm = 30º / 50mm = 25º

Time for 1º more for the micro bevel of either, can anyone tell me how many less millimeters to subtract from the projections?

[Walt Cheever]

It ought to me accurate enuf to interpolate: -2 mm for chisels and -2.5 mm for plane irons should give you a 1degree change.

Walt C

[AAvK]

Really cool, thanks Walt!