January 18, 2008 - Firewall Eyeball for Prop Cable

I had ordered from Spruce these steel "eyeballs" for the control cable firewall passthrough.  The throttle, prop and mixture cables are big so I ordered the eyeballs with the widest holes: .261".  That still wasn't big enough for the cables -- I needed some "lettered" drillbits:  H or I.  The local hardware store didn't have them and either did Avery or Spruce.  But McMaster-Carr did.  When it comes to that sort of thing, they have everything. 

I started by drilling out one of the eyeballs with the "H" bit and the cable fit perfectly.  So I drilled them all out to "H".
 

The eyeball instructions came with a paper template which I used to drill the firewall with.  I started with the Prop cable, using the dimensions on Van's drawings.

 
It took me a while but I finally got the thing mounted on the firewall. 
 
A close-up.  I went with the steel eyeballs because I didn't like what the drawings called for:  two plastic snap-bushings and some high temp RTV.  Everything on my firewall is steel. 
 
 
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