spar spacers

vans tells to make spacers 1.4380 thick i measured spar and they are a little thicker then this has anyone come up with a good number that the spacer should be thicker then the spar say one to five thousands? one of my bars is 1.4415 thick ( two spars but four places to measure top bar and bottom bar)

Unless things have changed since I built my RV-8 wings, there are two layers of material at the spar bars, and there may be a little bit of air between those two layers. I used a couple of C clamps to squeeze things together before measuring the thickness, to better simulate the way things would be once the bolts were tightened. I found that Van's numbers were pretty close.

I made my spacers from 5/16" nuts, 0.003" thicker than my spar:

http://www.kilohotel.com/rv8/article.php?story=20021022173215335

spar spacer


Just so happens I have these available in several widths.
http://www.bullerent.com/SparSpacer.htm