09/09/2007 - Its all gone green ...

The parts sent to Bob's have all been primed.  They look great as well, Bob has done me proud with this, i'm chuffed.

So the first rivets can be placed onto the airframe.  It all starts with the rear spar of the horizontal stabiliser.

Now a few builders have used longer rivets here than in the plans even though Van's insist the call out on the plans are correct.  Bob and I tried both and whilst the next size up certainly passed inspection using the gauge, Bob and I agreed they were not right and looked ugly.  The ones Van's want you to put in look great but dont pass muster using the gauge I had.  mmmm we did about 10 rivets using the standard size and I decided that I needed to do some more reading.

That same evening I did plenty of research.  On the forums there was lots of talk about whose inspection gauges were the best as they all differ a little.  Great I thought ! I read the books and they stated 1.5 times the rivet shank and 0.5 the rivet shank for the diameter and height of the shop head respectively.  I soon realised that was a rule of thumb and what I needed to do was go back to the military spec.

This can be downloaded here - MIL-R-47196A_MI.pdf

In the file there is a table that states how small the diameter of the head can be as a minimum and the min and max the height of the rivet can be.  Yes that's right min and max !!

Armed with my new information I went back into the garage.  How large a diameter is the hole in the gauge?  0.183" but what can the min be from the table; 0.163", so I drilled a new hole in the gauge at 0.167" which is basically #19 drill.  The rivets that Vans stated were about 0.175" failing the original hole in the gauge but passing the military spec by a decent margin.

Next came the height of the head shop.  The gauge has a 0.06" slot, but the range in the spec is from 0.05" to 0.07".  This meant the height was well above 0.05 but agian failed the gauge but are in spec.

I concluded that Van's were right and had stated the correct rivet, my gauge was adding a huge safety margin, and if I had not had Bob saying 'they cant be right' I would of used the larger rivets as other have done and been very close to if not over the maximum shop height specified as 0.07" for these rivets something which my gauge does not measure.

I drilled out the larger rivet, thanked Bob and called it a night.