Bevel Angle for Coffin Smoother

Re: Bevel Angle for Coffin Smoother

Tim of San Leandro

>The bevel angle will depend on the bed angle of the plane.....60 degree bed will use a different bevel on the iron compared to a 43 degree bed. The bevel angle will increase along with the bed angle. Hence...if 30 degree is a decent starting place for a typical, 45 degree bed bench plane....then a 60 degree bed might start with a 45 degree bevel. You'll want the increased bevel angle with increase bed angle to help strengthen the cutting edge - both against fracture/loss of sharpness and to fight chatter. Obviously.... a 45 bevel angle won't work on a 43 degree bed.

Bevel up is sometimes used as a scraper plane.....or done by persons without a clue ;-)

Tim....

and don't take my words too seriously, I'm a neophyte : )

Re: Bevel Angle for Coffin Smoother

R.J.Whelan

>Ray .. a good "rule of thumb" is bedding angle minus 10-15�. Having said that I break my own rule by using 25-27� on most of my bevel down planes - I find this angle gives the edge a bit more life between touch-ups ... rj

Re: Bevel Angle for Coffin Smoother

Jonathan Peck - N.Y.

>On a bevel up plane, the cutting angle is the sum of the bed angle and the bevel angle. If the bed is 45 deg. and you have a 30 deg. bevel, then you have a 75 deg. cutting angle.

Check the bed angle and sharpen the bevel to add up to the cutting angle you want and give it another try.

Theory?

WoodburnBob

>This surprised me: your experience that a 20 degree relief seems to give you an increase in edge durability (compared with e.g. 10 degrees). I've been experimenting in the other direction lately: putting a 37-40 degree bevel on Bailey/Bedrock planes. I'm still trying to find that break point where the relief angle is too small to allow the edge to cut.

I'd be curious, RJ, to know whether you free hand on the stone after establishing hollow ground shoulders, or whether you use a jig like the Eclipse. And, whether you generally just use a primary bevel, or put in a secondary ("micro") bevel. I'd imagine you've tried about all the various techniques and parameters; I'm just interested in hearing more about how you settled in with the technique you now use.

Re: Bevel Angle for Coffin Smoother

Tim of San Leandro

>John,

I've not seen a bevel up plane bedded at 45 degree's. 'course, as i posted above, I'm a neophyte. The bevel up planes I'm familar with are at 20 (block plane) or 12 degrees (low angle planes).

Tim

Re: I have one

Jonathan Peck - N.Y.

>I have a 24" craftsman made wooden try plane with a bevel up iron. I assume that the maker made it for a particular application and it has seen use, but I don't know what for.