On 2008-04-23, Steve W. wrote:
Dave99 wrote:
I've been trying to figure out the best way to do this for a few weeks
now, and I haven't come up with anything I like yet. I'm working on a
product where 4 pieces of 1/4" round aluminum need to be able to screw
onto four sides of both 1 1/2" OD aluminum tube and 2" OD tube. Both
tubes are .065. Picture a hat rack with the large tube being the
center, but that's not what it is. These parts will be assembled by
the buyer, so it has to be simple, and yes, it does have to be in
[ ... ]
Any mechanical geniuses have a good idea?
Countersunk Rivnuts?
That is what I would suggest, too. It helps to have the right
tooling, of course. The larger steel ones want hydraulic pullers, but
for aluminum ones (the most common), try ebay for the tooling:
320242645479 10-32 puller. (Called a "speed tool")
290223988051 100 10-32 Rivnuts.
Grip range .010 to .075 inch.
Scroll down to see what an un-set Rivnut looks
like. It expands in the middle to grip the
sheet metal from the inside, and leaves a
threaded section beyond that.
320242645759 8-32 puller. (Called a "speed tool")
190216705352 Three sizes -- but they don't say which sizes. :-(
Also called a "speed tool"
300218570212 Pneumatic powered -- expensive, but if you're
doing serious production it might be worth
while. This one is 6-32.
310043802502 Same, but 10-32.
(there are also 4mm and 6mm ones)
190217110740 Cheap, but you don't want this style if you have a
choice These are slow and clumsy.
My ebay search string is designed to skip a bunch of things
which I did not want when I was looking for these, and it seems to turn
up a pretty clean search still:
rivnut* -damper -"reference cd" -cessna -helmet -"belly pan" -ford
-raover -"cad plated aircraft grade bolts"
Note that for some Rivnuts there is a key on the underside of the
flange, and there is a separate tool for notching the hole for the key
to keep it from spinning inside the hole. It also has an angled handle
like the speed tool, but does not have the mushroom shaped handle to
pull out and in to spin the threaded arbor for the Rivnuts. This part
is where the "speed" come from. The tool has to be adjusted to a
specific set of Rivnuts and thickness of metal, but after that it is
every easy to use. Don't adjust it, and you can strip the threads out
of the Rivnuts.
Good Luck,
DoN.
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