Just a personal opinion on this. When I started doing the mechanical
rebuild of my snake, I decided to replace all of the BSF fasteners I
could get to. I purchased several hundred dollars worth of BSF nuts and
bolts from several sources. When I got to the point where I was ready
to install them, I concluded on closer inspection, that they were of
such poor quality, that I wouldn't to use. There were some places where
I didn't have a choice, like bolts that screwed into threaded castings,
but these where places where clamping force and strength were not
critical. In one case, I did have a new piece machined with UNF threads
because I felt strength was an issue.
No major manufacturer makes BSF fasteners anymore, so you generally
don't know what you are getting when you do buy them. What I ended up
doing was buying AN grade fasteners from Coast Fabrication in Huntington
Beach, CA. There are number of other sources for these fasteners, one
being Aircraft Spruce. If there is an aircraft parts supplier in your
area, it's likely they either stock them or can order them.
When it came to the seats, I removed the rusted original 1/4" coarse
thread British screws and replaced them with high strength NAS 1102
screws. In my case they were secured with nuts, so the thread type
didn't matter. Also the maximum length for these screws in the
Coast catalog I have is 2 1/4", so they wouldn't be applicable for a
Tiger. I choose extra strengths bolts (160 PSI, tensile), because I
don't want my seat to get ripped loose if I get into an accident or
someone rear ends me. This is probably over kill, but it's way way
better than the original God-knows-what-grade screws.
I don't recommend using stainless fasteners anywhere where strength is
important. They are not even as strong as grade 5, and probably not
even as strong as the re-manufactured BSF stuff.
Roland
>From: "John Slade" <edalsj@igs.net>
>To: <Sjhcobra1@cs.com>
>Cc: <tigers@autox.team.net>
>Sent: Wednesday, September 18, 2002 11:19 PM
>Subject: Re: Seat screws
>
>
>Since we didn't seem to be getting anywhere, I went to my spare set of
>seats which have never (to my knowledge) been taken apart, and removed
>one of what I think are the screws under discussion.
>
>It measures as follows:-
>
>head.....flat head, slotted, 100 degree underneath
>length.....2.46"...call it 2 1/2"
>diameter.....0.246"...call it 1/4"
>thread.....fully threaded 26 tpi
>
>This screw equates to 1/4 British Standard Fine
>
>
>Hope this helps
>
>John Slade
>Manotick, ON
|