Barry Schwartz wrote:
>I'm not sure which inserts are being discussed (so I may be off base here)
>, but I can say (I've been a mechanical designer for over twenty years now)
>that unless this type of insert is installed from the backside of the hole,
>and the insert has a flange more or less clamping the parts together much
>like a bolt and nut, then it won't be as strong (pull-out force) than a
>properly threaded or heli-coil inserted hole in this application.
I too have been a Mechanical Engineer for over 13 years with over 9
years of that in the Aerospace Industry. The rest was in the Automotive
business.
Enough of the resume.
If you wish, I can send you a copy of the Military Standards for the
inserts I'm talking about.
>Most press in inserts I've seen are for sheet metal or for plastic molding wh
>where it is ultra-sonically 'welded' into the material. I've yet to see one
>strip the threads when it fails. Typically the insert pulls out. A
>pressed in, blind hole application (installed into the same side as the
>fastener is installed) depends solely on the material being displaced and
>cold forming around the insert to secure it in place.
These inserts have four barbs to hold onto the host material once they are
screwed into the hole. These are not just inserts, they have threads on
the outside too. They are installed the same way as helicoils, but with
the barbs,
resist more shear.
>The heli-coil offers more resistance to pull-out, as long as there is
>enough >material around the repair, by providing a larger surface area
>(bigger threaded >hole, in effect a larger stud) than the original one.
I'm very sorry, I don't buy that.
I feel that these inserts are the best idea. They perform to our
Military Standards for everything from rockets to jet airplanes to
helicopters. I'm sure that they will more than be sufficient for my TR250.
Steve
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