rjcthree

rjcthree

Well Known Member
It appears that the case bolts, etc, that I removed from my H2AD are nothing special - as in it's a place if I wanted to use some fresh fasteners, I can use AN hardware.

Or I could pay $1.48 per 1/4-20 bolts from Lycoming - maybe not!

THoughts? Rick
 
Hardware

Rick:

I'm not sure that I'd use AN bolts here. If you're not going to certify your engine (ie: experimental), I should think grade 5 Hardware Store bolts, nuts and washers would be sufficient. If you get really paranoid, use grade 8.:D

The 1/4in. bolts around the case halves only get torqued to 70 in. lbs.
 
I'd go with the AN hardware as long as you're talking about the hardware around the case perimeter.. Quality control is a lot better with AN-spec hardware than with ANY of the hardware store stuff, regardless of grade.
 
I was thinking about this when I tore mine down as well. The parts catalog shows 16 of the std-1215 bolts for the case. ECI has a PMA'd version for $1.32. Even with the washers, I don't think new hardware would add up to all that much.

I started a spreadsheet a while back with a per-figure parts breakdown and cost from the catalog. I'll see if I can finish it off and send it to you tomorrow Rick.
 
Come on Guys!

X-rayed, Non Destructive Testing for 70 in. lbs???????????????:eek:

My goodness we might die!!!!!!!!!!

Notice that these bolts are 1/4in x 20 threads. NOT the normal 1/4 x 28 AN threads. 1/4 x 28 threads torqued to 70 in. lbs will exert more clamping pressure than is necessary for the flange. You can find 1/4 x 20AN bolts but WHY???? Grade 5 hardware bolts are more than what is necessary here and are much easier to find!
 
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Why not hardware-store bolts?

Because I have PERSONALLY twisted the head off a 1/2" x 13 Grade 8 bolt (non-aviation project) with nothing more than a Craftsman 3/8"-drive ratchet & socket on the bolthead, and a wrench on the nut. No cheater bars, no power tools... and I'm no Hercules, either.

OTOH, I've personally seen Grade 8's resist the TQ applied by a 220lb mechanic doing pull-ups on a 4-foot cheater bar over a 1/2"-drive breaker bar.

In other words, the quality of hardware-store hardware is inconsistent, and that's why I won't use it on any aircraft I work on.


My opinion - worth every cent you paid for it...
 
Wrong? Nothing, really

The hardware removed is just ugly and painted over and oily. I would like the paint to stick to my new motor. I may just soak them in thinner and see, but I'm sure I lost one or two along the way . . .

And I've suffered H2 embrittlement before in my work life. I know, just bake 'em out . . .

I will replace all the locking HW and washers for sure, that's a simple matter.

The H2AD/H3AD used 1/4-20 case bolts, generally more standard pitch HW all around, for those of you that noted the difference.

Rick
 
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