cutting valley rafter 'v-groove'

[bigshow]

What tools are typically used to cut the v-groove of a valley rafter?  seems to me that a 16" circular saw doesnt have the depth.  I'm good with a chainsaw (scandinavian scribe log building is what i'm best at), but i dont think i should eyeball it on a TF valley rafter.  I saw the miter mill...which i'm pretty much dead set on over a 16" circ..but just wondering is actually being done in the field....


thanks...

[Jim_Rogers]

Back in 01 when I was at Fox Maple timber framing school in Maine, I saw students cutting valley rafters.
They always cut the valley last after all other joinery is done.
Here is a shot of two students with the valley piece removed from the valley timber.



They did use 16" skil saws to make these cuts....

[maineframer]

Bigshow,

The v-cut in a valley is called a "backing cut" and it is generally cut with a large (16") circular saw. We sometimes first cut this with a worm drive  and finish the cut with a 16" saw. This will put alot less strain on the large saw and also give you a nice kerf to follow.

David

[bigshow]

Ok....that being said, you guys seen the miter mill?

http://www.accutechinnovations.com/id15.html

I cant see the downside compared to 16" Circ.  Greater depth of cuts, power of a chainsaw.  I found the Makita 16" to appear to be fairly underpowered when gang cutting birdmouths.  My Stihl seems to cut much more nicely when doing big jobs like log purlins and rafters.  Only thing i can see as downside is compensating and setting up for chainsaws huge kerf.  I'd like to hear the cons.....