Date: Sat, 13 Oct 2018 11:10:26 -0700
Reply-To: Neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Neil N <musomuso@GMAIL.COM>
Subject: Re: LVC. Bracket Design: Captive Nuts; A "Last Resort" ?
In-Reply-To: <78902273-0426-4758-B2F7-E9A0E4E75C15@gmail.com>
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Thanks Jim.
Maybe I've been lucky in the past but for the stuff I'm doing, I've
been able to tack nuts fairly accurately. Or, rather, positioning
inaccuracies have not reared their ugly head yet. LOL.
On one part, I recall tack welding a flanged type nut .jpg image link:
https://images.lowes.ca/img/p400/13173/008236712094_ca.jpg
so in hindsight, that flange might've helped spread out weld heat so
it wouldn't distort the nut. Regardless, the flange helped keep nut
aligned flat to the parent metal. I either bolt the nut to the work
then weld it or just clamp it.
At the risk of boring folks to death with exhaust design talk, the WBX
position 50º ABA I4 VW engine I've installed in my 88 Vanagon locates
the muffler fairly close to the rear apron. Lowering the engine to fit
under the cover added space between crank pulley and rear apron but
positioning the WBX 1.9 muffler end as close as possible to the engine
side diesel Vanagon exhaust bracket located the cat/muffler flanges
close to that diesel Vanagon exhaust bracket. Since the bracket I made
to to adapt those parts had to be short, space that kept getting
"taken up" became more critical. So, it's one thing to see and know
you're adding thickness to the diesel bracket but it's another thing
to find that after tack welding on a plate, the bolt that did pass
through now has to pass through other side of the bracket. Rookie
mistake. Ovalling the bolt holes in new plate is an option but my Plan
B of captive nuts makes more sense.
Thanks for point to riv nuts and "x" metal cage tip. I'll look that up.
;)
Neil.
On 10/13/18, Jim Felder <jim.felder@gmail.com> wrote:
> In Army machinist school we were never taught that there was a right
> component to tighten. Captive nuts that are truly captive—welded to the
> material part—have to be very precisely aligned. Plus not everyone has a way
> of tacking down a nut without screwing it up. The other way is to make a
> sheet metal cage out of an X of steel that captures the nut but let’s the
> nut move around enough to engage a bolt entering at an imperfect angle or
> position.
>
> And then there are rivnuts. The sets with the big pliers are very expensive
> but lately I have seen them with small wrench operated systems.
>
> But another option for you is to just take the part you make to a racing
> shop and see what they can do for you without buying and experimenting with
> a bunch of stuff.
>
> Jim
>
> Sent from my iPhone
>
>> On Oct 12, 2018, at 2:41 PM, Neil N <musomuso@GMAIL.COM> wrote:
>>
>> Application: custom muffler bracket mounted to a VW I4 gas engine in a
>> Vanagon.
>>
>> From a design standpoint, for parts using nut & bolt fasteners, since
>> one tightens the nut to the bolt, are captive nuts more or less a
>> "last resort" in terms of design?
>>
>> With captive nuts, I guess that since the nut wouldn't have a washer,
>> maybe tightening the bolt to the nut still provides a proper union?
--
Neil n
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