REFLECTOR: Threaded hole strength

[Kufalk]

Chuck,

I am building an XLRG with the fast build fuselage and I did the "really big
hatch" mod.  I want to have the hatch cover secured with no visible hardware
from the outside.  I made a molded flange along the leading edge of the
hatch to hold the front in place.  Now I am going to put 2 or 3 hardpoints
along the aft edge to hold it in place from underneath.  I am going to use
large thumbscrews that I can reach from behind the panel.  I am thinking
1/4-20 will be strong enough but I may use 1/2-13 thumbscrews because they
have a larger head and would be easier to tighten by hand.  I may use fine
thread if I can find a fine thread thumbscrew I like.

Darrell Kufalk


----- Original Message ----- 
From: "Chuck Harbert" <c.harbert at comcast.net>
To: <reflector at tvbf.org>
Sent: Wednesday, July 20, 2005 11:32 PM
Subject: REFLECTOR: Threaded hole strength


> Okay, I'll bite. Now where are you using this plate and bolt in the
> airplane, because neither fine or coarse thread is going to be very strong
> going into only 1/4" aluminum?
>
> Chuck H
>
> > --------------
> > Yes, the larger thread diameter gives more area in shear around the
bolt,
> > therefore the ½ " bolt connection will take more load.  Also, the larger
> > thread (13 per inch, rather than 20 per inch) also makes each thread a
bit
> > stronger.
> > Keith
>
>
>
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