DC Piping - Which is better Bend

[tim walker]

For a drop from my ceiling and then on florr to tools, which is better for a 90 deg turn? A radius elbow or two 45's

C:\Documents and Settings\Tim Walker\My Documents\woodworking\Elbow.htm

C:\Documents and Settings\Tim Walker\My Documents\woodworking\2 45's.htm

[Cliff Holmes]

I did some testing recently and found them to be roughly equivalent. Two 45s butted end-to-end did slightly worse than a WR elbow and two 45s with 12" of pipe between them did slightly better than the WR.

[mickey cassiba]

In the moulding plant I use spiral bent on a very wide radius for the high output machines(moulders and the Straitoplane) and double 45's with a piece of straight between for the chop saws and rips. The only problem I have is the scrap chipper which produces a phenominal amount of material. the ten inch can barely handle it at times, and it's located at the beginning of the main trunk with a non-shared duct. Gotta rod it out regularly.
Not a home shop setup but the concept is similar...wide easy turns make for better extraction. Big chunks get hung up very easily in sharp turns, as do the "strings" from long rips. Not to mention the gloves and trash that our operators feel compelled to throw into the inlets.