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Firewall passthroughs?

G

gfb

Well Known Member
Trying to figure out the firewall passthroughs I will need for my RV-9A / IO-340 (FP prop.) Do any come with the Vans FW-FWD kit?

Looking at the Cleaveland options. I know I need two of the stainless passthrough kits (SA-05) for sensor wires, etc. I suspect I also need a number of eyeballs for control cables? Seems like they have Alum or steel? Also a different model but I can't quite figure out the differences or which ones to get (and how many.)
FPT1S or FPT1 or FPTTTP? I suspect Throttle, Mixture, Heater, Alt Air?

Also, what should I use to make the holes for the above? (and the heater hole.) I have seen people mention special mandrels that make those larger holes but they are quite pricey for something I will use once or twice per size?

Thanks!
 
Punch

For the larger holes, like the heater, find an electrician friend who has access to a Greenlee punch tool kit.
 
...OR find someone with a set of Rotabroach bits. They go thru the stainless firewall like the proverbial hot knife. The Rotabroach set is too pricey to buy; they're only practical if someone will lend them to you.
Some EAA chapters have a tool crib, in which case the Rotabroach set can be used by many.
 
A more time consuming option: Try drilling a lot of #40 holes around the perimeter of the desired opening, then use a rotary cutter to remove the material between the holes. I know, it's a lot of drilling through steel, but a good bit with lubrication should make it slightly less onerous.
 
RVTrumpet said:
A more time consuming option: Try drilling a lot of #40 holes around the perimeter of the desired opening, then use a rotary cutter to remove the material between the holes. I know, it's a lot of drilling through steel, but a good bit with lubrication should make it slightly less onerous.
Click to expand...
I did it this way too. I figured it was easier than chasing down a punch.
 
I bought a set of punches from Harbor Freight and they worked just fine for the passthroughs (including all of the control cables).

Use a unibit to get the initial 3/4" hole started, then use the punch to enlarge this to 1 1/8" for the pass throughs. I used a 1" diameter pass through from Safeair1.com (no longer available).

IMG_3166-M.jpg
 
Unibits seem to work well on stainless. HF has a cheap set of three and the big one goes to 1.5", I believe. For the big heater hole, I roughed out the hole with a cut-off wheel and finished it with a carbide bit on the die grinder. Only took 20 minutes.

Larry
 
Digidocs,
Do you know the spacing of the mounting holes on that firewall pass-thru? I have the older stainless steel grommet covers and would be interested in switching them out if the mounting bolt patterns matched.

-Jerald
 
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