View Single Post
  #9  
Old August 10th 06, 06:54 PM posted to rec.aviation.homebuilt
[email protected]
external usenet poster
 
Posts: 217
Default Flying on the Cheap - Wood


wrote:
...

Any mention of splicing spars usually sets several heads of hair on
fire, even though such splices are an accepted practice, their details
fully covered in the old CAM or the new AC13 manuals. In fact, once
you've made up a suitable fixture to ensure all of your splices will
have the same angle, doing a long-splice in solid wood is no more
difficult than doing a short-splice in plywood. (Hint: Solid wood,
you want an angle of about 1:15. With plywood, thanks to the
orientation of the plys, you can develop full strength with angles
between 1:10 for mahogany and 1:12 for birch. As a point of interest,
boat builders commonly use 1:8 for either.)

Making up a scarfing fixture tends to drive a lot of homebuilders crazy
as they fiddle and tweak, trying to achieve a precise angle of 3.8
degrees for a long-splice. Or 7.1 degrees for a boat-work 1:8. The
truth is, the precise angle doesn't really matter. What matters is
that all of the pieces be cut to EXACTLY the SAME angle... and that the
splice be strong enough for the task at hand. This degree of accuracy
can be achieved using nothing more complicated than fixtures assembled
from scrap wood, one for scarfing solid stock, the other for scarfing
plywood. In each case the wood gets clamped in the fixture and the
same cutter - - a portable circular saw - - is used on both.


I recommend that Fred pick up and tune a couple of hand planes.
At the very least I think he'll find a block plane and and jack to be
useful, especially for those scarf joints. Old Stanley, Union,
Ohio Tools, Sargent, Millers-Falls, KeenKutter, Winchester, or
Fultons are excellent, and better than any new planes found in
the Borgs today.

--

FF