"Flattening" Chip Breaker

[custard]

If I understand David Charlesworth's technique correctly, is it basically the same as what's being done in this video (except with a 3mm difference rather than whatever is being used here)? https://youtu.be/fVfJxDFNinc?t=211

That's exactly right. 3mm or 12mm probably wouldn't make much difference on the highly arched cap iron you find on most Bailey style planes, but there are other other designs of cap iron (such as the Record Stay Set or the Lie Nielsen design) which need the shallower angle that 3mm delivers.

Once you've got more experience honing and sharpening then you won't need this support ramp, but if you're just starting out then a ramp like the one in the video you linked to will ensure you're consistent and accurate, which in turn will get you to a satisfactory conclusion more quickly than just rubbing away with your wrists flapping up and down so the angle keeps changing all the time.

 

[El Barto]

Thanks Custard