width of blade root

[imsmooth]

I am almost done with my 5' 1" blades made of cedar.  They are 10" wide at the root.  I have three holes for bolts that will wedge the root between two 3/4" thick marine plywood discs at the hub.  If I cut the root to 6 1/4" will this be adequate?  Right now it is about 8" wide x 5" long x 2 1/2" thick.

[Flux]

Yes.

Glue the discs to the blade roots or add a significant number of wood screws, the bolts are fine but they only contact the root at one point. This is a far weaker issue than the blade root size that seems to worry you.

Flux

[imsmooth]

With disc washers and 3/4" plywood I would think that the discs compress the root over the whole 6" x 5" surface.  True, there are only three bolts for each root, but the entire root is sandwiched between the discs.  I don't see how wood screws add any more stability.

[Airstream]

This is a zero tolerance for movement area - any creep after balancing will amplify itself into progressing toward a dissembled state. To 'weld' the structure together means multiple methods of fastening. Washers can/will crush the substrate they are over - then what's the assemblage to do? Eight or ten gnarly screws will hold the disc to each blade root while the bolts continue to key into the hubs rotation even if they are not tensioned perfectly from wood compressing under the washers...