On 24 Oct 2013 03:27:31 GMT, "DoN. Nichols"
wrote:
On 2013-10-23, Larry Jaques wrote:
On 23 Oct 2013 04:42:35 GMT, "DoN. Nichols"
wrote:
On 2013-10-23, Larry Jaques wrote:
On 22 Oct 2013 21:58:52 GMT, "DoN. Nichols"
wrote:
On 2013-10-22, KG wrote:
I have a problem holding thin aluminum, about .080", together for a period of 3 - 4
months in an outdoor environment. I have tried drilling and taping with # 8, 10, 12,
fine & course thread machine bolts, which last a few cycles then strip out. The force
needed is about 3 - 5 lb compression. I only have limited access to one side of the
joint. I'm now thinking of a finer thread screw such as drywall screws which are
designed for metal studs. Any thoughts or suggestions??
Lloyd, where is the part which says he wants to take them apart?
I saved a post and doubled up in this one, OK? 
O.K. But no comment about the part quoted below where I
explained at least why *I* read it as implying semi-frequent
disassembly?
My mind read "thermal cycles", as in night/day changes, so I didn't
want to get into it. After rereading it a few times, I came to side
with you on that, too.
Where is Lloyd in this thread? (at least the part quoted here).
But I read the "which last a few cycles and then strip out" as implying
that it if fairly often removed and reassembled. (Removal/tightening
cycles of the screws.) Granted -- he may not have meant that, but then
again he may have.
[ ... ]
If there is space behind the plate, another option might be
Rivnuts. They fit into a drilled (and countersunk if need be) hole, are
drawn somewhat like pop rivets, and provide a much longer thread.
I bought one of the HF gun kits and used it on my '91 F-150 doors to
hold the trailer mirrors on. Worked like champs for years, and AFAIK,
are still working. For $17, you cannot go wrong. Maybe he can use one
of them.
http://www.harborfreight.com/45-piec...-kit-1210.html
I *think* that those are Rivnuts stood on their heads and
photographed from nearly straight above, so it is hard to see for sure,
particularly with the rather low resolution in the photo.
Yeah, they're nuts with shoulders/collars built in. You drill the hole
and put the nut through it, then when you pull the trigger, it
collapses the shoulder around the hole and secures the nut. Unscrew
the tool and you're done.
Yes. The "Nutserts" are two-part items, in which the threaded
part expands an outer collar -- in contrast to a "Rivnut" which is a
single piece and which has a part thinner which expands to hold it
firmly in place.
HF's jobs are real (knockoff) rivnuts, then.
The old rivnuts we used at Southcom were swaged in from behind. Those
had angled shoulders which the nut itself filled in when it was
swaged.
Yet another style -- and not matching the Rivnuts as originally
made and sold by B.F. Goodrich -- the ones who own(ed) the "Rivnut"
name.
OK. Those I inspected with were very thin, maybe 1.5-2 threads, max.
I had fun as a QA inspector until I took it into my entire life.
Everything became go/nogo and it damnear kilt me, increasing my
already far too high intake of alcohol. I'm glad I was able to walk
away from both. I sure learned a lot there, though.
[ ... ]
As for the HF set -- I don't *ever* consider only ten of each
size to be useful -- even assuming that you get it right the first time
so you don't have to drill one or two out. Personally, I consider a lot
of 100 of a given size a better starting point. :-)
I used 3 and have had the set for 20 years since, so I'm fine with the
smaller sets. If it was something I used weekly, yes, sets of 100
would be a good thing.
O.K. I sometimes use twenty on a single project.
I've been surprised that I haven't needed/used more of them, too.
You'll be happy to hear that replacements are sold in bags of 100.
The tool shown in the auction above has to be adjusted for both the
size of the Rivnut, and the thickness of the sheet metal into which it
is being installed. Get it too loose, and the Rivnut will turn
(especially if you have the ones without the key), and get it too tight
and you strip out the threads. I don't see provisions on the HF tool to
make such adjustments, though they may exist.
Thread the tool's screw back in and give it another OOMPH! ?
If it did not draw in fully -- but not very useful if you strip
out the threads by over-drawing. :-)
True, but with all those threads, it's less likely. I'd also likely
try swaging with a small chisel around the squozen side to keep it
from rotating. Back up the nut onto something solid and tap the
chisel down perpendicular to the axis in a few places around the
threaded area...
|
-0- (but tighter to the hole)
|
[ ... ]
Anti-seize is cheap.
If you can get enough of it to prevent corrosion forming, and
keep it there, yes.
I don't recall having any trouble with any screw or spark plug I put
a/s on, ever. I've had one tube of aluminum-based a/s for 35 years
now and it's going strong. I don't do much with aluminum, so maybe
that makes a difference. It works well on s/s to steel, steel to
steel, and steel to aluminum head (spark plugs), though.
But that is a much thicker piece of aluminum, thick enough to
have a number of threads engaging -- not the one or two threads which
would happen with the aluminum thickness described in the original post
(0.080"). A 12.5 TPI (2mm pitch) screw would only get one thread in the
metal. 32 TPI (e.g. 6-32, 8-32 or 10-32 to name common ones which I
believe the OP mentioned) would only have 1.6 threads in the aluminum
sheet.
Isn't that why we're suggesting rivnuts? To get away from the
single-thread security? But I was thinking in terms of the rivnuts
rather than a single sheet. I probably wouldn't keep anything around
which broke so often, reengineering it to a higher performance the
second time it died, if not the first. Aren't we all wired that way?
g (Here on Wreck.Metalheads, anyway.)
Where have you had trouble with a/s?
I haven't -- but I've also not used it to try to prevent
corrosion in a very shallow thread engagement. I would think that it
would be more likely to wash out (in a rainy environment) -- especially
if he keeps removing and re-installing the screws. :-)
You're most likely right.
--
Worry is a misuse of imagination.
-- Dan Zadra