Dear Riveters
The great thing about a solid AlCu alloy rivet is that it expands to fill
the hole allowing full shear/bearing strength to be developed with just a
low tolerance drilled hole. To get the same bearing/shear performance from
a bolt it would have to be a super precise fit!
An 1/8 rivet is designed to go in a hole made by an 1/8 drill (carefully
drilled straight with a drill in good condition).
Much more important is that the head sits down flat and that a well upset
tail shape is achieved with the right amount of upset.
Merry Christmas..........MARK WILKSCH
-----Original Message-----
From: Fred Fillinger <fillinger@ameritech.net>
Date: Saturday, December 23, 2000 06:06
Subject: Re: Rivet hole Tolerances
>Not even our FAA's bible (Acceptable Methods/Techniques Handbook) is
>specific, just if loose, drill to next size rivet. I'd think a few
>thousandth's slop is OK. Three things strike me here about the
>problem. 1) The shear force that will be applied at worst case to the
>six rivets is in the hundreds of pounds range, a small fraction of
>what the six "AD" type (hard) rivets can take at 38,000 PSI and
>properly set; 2) CS09 needs to be chamfered to fit the bearing, so if
>done neatly, the bearing housing takes some/most of the shear load; 3)
>the assembly is attached to a flexible structure (cockpit module),
>also diverting some of the load.
>
>So, as non-engineering opine mindya, if worse than a few thousandth's
>slop (a 9/64" drill would have given you 15), I'd just assemble it
>with Redux, at the CS09 chamfer and in the rivet holes. Might want a
>film of wax on CS09 to ease bearing replacement.
>
>BTW, to deal with just-a-hair too small 1/8" holes throughout the
>build, I used a miniature, hobby-store, rat tail file. Pretty well
>worn by now...
>
>Regards,
>Fred F., A063
>
>> Gidday,
>> Can someone please tell me the tolerances required for safe building
>> practice when it comes to drilling holes for rivets? I am sure that any
>> solid rivet can only sit in a hole of a certain size i.e. too loose would
be
>> unacceptable. I have loose rivet holes in my CS09s that support the pitch
>> torque tube laterally and elevated above the floor of the fuselage, the
>> lateral triangular brackets with the snuggle plates bonded onto them. I
feel
>> that should I hand set these bearings to the CS09s that the spreaded
rivet
>> heads will swell and set OK, but that the shear load on them will be
taken
>> up only on the top surface of the flange that mates with the underside of
>> the rivet end that has been spread. Within the cross section of the union
of
>> the 2 parts the rivet would be correctly loaded through the snug bearing
>> holes but then be bassically unsupported within the CS09, but under a
>> compressive bond from the rivet that concentrates the shear load on the
>> underside of the rivet base. It all sounds a little bit complex, and
maybe I
>> shouldn't worry. Has anyone else worried about looseness in the mating of
>> various rivetted components? Any assistance would be appreciated
>> Reg
>> Tony Renshaw
>
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