Sonex Bending Flat Parts - Manual (Page 2)

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Builder's Guide
Homemade wood V-blocks and rods of various diameters.
While solid steel rods are shown here, wood dowels and steel
pipe would also work.
Forming Parts with a V-Block
V-blocks can be made from scrap wood (2 x 4s work well)
and the forming tool can be a scrap piece of steel rod, pipe, or
wood dowel of the correct diameter. A bench-top arbor press is
all that is needed to press the aluminum part into the V-block.
Creative builders have also used a car jack as a press.
V-Block Dimensions
The V-block in these photos was used to form all the 3/16"
thick parts for a Sonex airframe. The top of the "V" is 3-1/4"
wide, and it is 5/8" deep. The block was made from a piece of
2x4 lumber.
Forming Parts
1. Mark the centerline of
the bend on the part. Be
sure to mark the edge of
the part as well, as this is
all that will be visible as
the radius rod is taped in
place.
Note: When forming a part
with a V-block, the bend's
centerline must be marked.
That line is centered between
the "bend tangency lines"
shown on the plans.
The bend centerline is marked
on this Sonex spar fitting.
2. Tape a steel rod, pipe, or wood dowel of the correct diam-
eter on the part, centered over the bend centerline.
Note: The proper diameter for the forming rod will be
twice the bend radius identified on the plans (e.g. a bend
radius of 1/2" requires a 1" diameter rod).
3. Center the bend center-
line of the part over the
center of the "V" in the
V-block.
The rod taped to the centerline of the part.
4. Apply pressure to the rod
until the part has been
formed to the proper
angle.
The rod taped to the center-
line of the part and centered
over the "V" in the V-block.
Bending Flat Parts