The 'Right' Angle

For a number of years now, I've been using a Kell III honing guide,  which in combination with a few 'bench hook' projection boards, enable a particular honing angle to be repeated each time.

So far, so good.

This is a shot taken a while ago and you can see that there are a couple of boards for Bevel Up (BU) and the one in the foreground is for Bevel Down (BD) blades.

I've also been exclusively using LV BU planes, with a bed angle of 12deg, so in theory, to get more or less the correct honing angle or around 45deg, I should have been using the BU board, top right.

Except I wasn't.

Some while ago, those boards were replaced with others and I never got around to making the correct individual board for the BU blades...I kept on using a 30deg one, which of course meant that my effective pitch was now 42deg, which for practical purposes is a mite too low.

So how did this wondrous discovery come about?

I've recently been using some American Cherry, which is pretty benign stuff, but there's a tendency for it to 'tear' on the quarter sawn face...which was happening quite alarmingly as I was merrily planing away.  I then went back to the honing station and had a look at the projection board I'd  been using...

...and then the penny dropped!

I've now made another little board with a projection of 40deg, so now my effective pitch on all my BU blades is 52deg...

...and no more 'tear out'.