replying to James, Dan wrote:
If you must have a 1-pass cut on a 6x6 or larger post or beam, then I
would suggest you invest in a bandsaw. These will cut much deeper than
6x6, produce a very fine cut or notch w/no overcut & can also be used for
re-sawing old lumber & many other projects. Alternatively, you can
purchase a Prazi Beam Cutter attachment for a circular or wormdrive saw (I
would recommend the wormdrive for more power on large beams). The Prazi
will cut up to 12" in 1 pass. There is also a 16" circular saw from Makita
that is used in the Timber Framing Industry.

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