Mailing List flyrotary@lancaironline.net Message #42107
From: Ernest Christley <echristley@nc.rr.com>
Subject: Re: [FlyRotary] Re: Metric Bolts
Date: Thu, 27 Mar 2008 14:45:42 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
wrjjrs@aol.com wrote:
 There is absolutely no reason to have a hardware failure. None of us should be using non-AN nuts and bolts for any sagnifigant part. Come on guys this is not an area to scrimp.
  
This is the Flyrotary list.  Every one will have to use a great many non-AN nuts and bolts for a very significant part...the rotary engine.  There are no AN metric parts.  It's not just about saving a few cents.  Aircraft Spruce and Wicks prices are not out of line with other quality bolt distributors, but their online catalogs don't even list any metric bolts that I could find;  though, I seem to remember some of the same zinc plated stuff that Lowe's has listed in ACS's printed catalog.

You can run a test on the bolts you get.  A spring type torque wrench and a block of aluminum.  Mount the head of the bolt in a vice, pass it through the aluminum, and apply the torque wrench until the threads strip.  A couple from various batches will let you know real quick what is usable.  I used lots of the hardware store Class 5 1/4" bolts to hold parts together when welding.  The Class 3 were not strong enough to be worth keeping around, and I didn't want to weld around the cadmium plating of the Class 8 or AN bolts (burning cadmium is a carcinogen).  The AN were no stronger than the Class 5, by measure of my semi-calibrate wrench hand. The Class 5 hardware stuff is worth crap for corrosion resistance, though.  I had the oil pan stuck on the bottom of my engine for a few years, while it sat at the back of my workshop.  Used some of the Class 5 hardware store bolts, because the original oil pan bolts weren't long enough.  About half came out with powdery white rings of corrosion.  The trick is going to be finding a good selection of cadmium plated, Class 5, drilled-head, metric bolts.  Then put together an order list that will cover most everyone's needs.
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