Firewall Penetrations and Heat Selector Box

While I wait for some shipments, I took the time to work on some odds and ends on the firewall.  First the two upper holes with the red fire sleeve are for wire pass throughs.  Basically on the right will be the high power wires and on the left will be the engine sensor wires.  For all the holes I used new hole saws from Lowes.  They worked well and the 1 1/8 inch saw cut 5 holes and can still go for more.  The firewall is made of stainless steel and is quite sharp and hard to cut so I am glad these hole saws worked well.  It was a bit tricky I actually used a fairly fast speed and boe-lube to make it cut fairly cleanly.   All the holes came out well.  These pass throughs are about 1 inch above the top firewall cross angle and 1.75 inches outside of the upper ribs.  These spots should work out with no conflicts.

The next stepw as 3 cable pass throughs that will be for the Mixture, Prop Speed, and Throttle.  These were placed per the plans and came out well.  The throttle is the one by the heater box down low on the firewall.

Finally I cut the 2 inch hole for the heatbox.  I was worried about this one, but other than lots of noise, smoke and sharp edges it went really well.   I just used emory cloth to clean up the edges and dull the sharpness..  On all the holes I can run my fingers without risk of cut, that is effectively deburred.

I also hooked up the cable for the heater box and worked it a few times.  Functions smoothly.