Wing Spar – Setting Solid Rivets

QUESTION to Sonex Tech Support:

Plans page: WIX-W14

I am setting the solid rivets in the wing spar. Perhaps I am being
hyper-critical of the outcome of each rivet set. I am using the ‘big bolt’
method with the bucking bar on my garage floor, with the factory head of the
rivet against the bucking bar. After setting the rivet, the factory head has a
flat spot from being pressed against the flat bucking bar. Can I assume that
is acceptable, and that I am not missing something else I should be doing?

Thanks,
Kevin

ANSWER:

Hi Kevin,

Flattening of the factory head using this method is normal.

Sonex Aircraft Tech Support
Sonex Aircraft LLC

Wing Attach Blocks

Plans Page: WIX-W16

The wing attach blocks are shown on the plans with 3/16″ pilot holes and then two are used to bolt the block to an angle piece with AN4 bolts in “tight fit” holes. With my drill press, I found the best way to get the tight fit holes was to up-drill using a “D” bit and ream using a .2470″ reamer. I followed the following steps:

– Cut and sized the blocks, polishing off all the tooling marks and scratches with scotch brite.
– Drilled the (2) 3/16″ pilot holes. I did not drill the third 3/16″ pilot that will eventually be used for the wing pin.
– Aligned the spacer plate on the angle and clamped in place and drilled through it using the 3/16″ hole that was in the angle from the factory.

– Positioned the block on the angle/spacer, and clamped it in place so that the mark for the eventual wing pin hole in the block was aligned perfectly in the center of the 3/16″ pilot hole in the angle (and now spacer also).

– Drilled through the 3/16″ holes in the block into the angle.
– Up-drilled those (2) holes to “D”
– Reamed those (2) holes to .2470″
– Drove the AN4 bolts through and torqued down the nuts (nylock nuts to be replaced later if I need to loosen/remove for any reason for future assembly steps)
– Clamped in the other direction and drilled the 3rd 3/16″ hole (for the wing pin) through the block.

Wing Spar 2

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Plan Page: WIX-W16

Making the wing attach blocks. I had been using the 7tpi blade on the bandsaw but it was struggling to cut through this bar stock. I replaced it with a 14tpi blade and it cut through the bar like it was butter. I can’t wait to try this new blade on the thin material to see how it does. Should be smoother, faster, more controllable, and more quiet.

After the initial cut, I used the vixen file to get the length close to the final 1.75″. It is amazing how much material that file can take off quickly and easily. Then I got it to final length with the scotchbrite wheel. Next I used the vixen file to give it the required chamfer. A touch up on the wheel and it was done.

Next up: Drilling holes

Cut easily with the 14tpi blade

Filing to length

More filing

There it is, on the plan

Like a sparkling jewel!

Wing Spar 1

Plans Page: WIX-W16

Many of the parts on this plan were supplied as part of the optional machined angle component upgrade. Just had to cut the spacer from .060 sheet stock and cut the wing attach blocks from bar stock. Then drill the wing attach blocks.

Parts on the plan page

Pre-made parts highlighted

Had to cut these from supplied sheet of .060

Need to fab the wing attach blocks from this bar stock