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Posted by: Kubtan

04/21/2004, 16:38:34

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Hi team,

I have an application on the shop floor where a screw is driven into an insert.  When the screw is tightened with a torque-limiting gun, the insert sometimes pulls back unevenly, collapsing on one end more than the other.  When this happens, it causes the screw gun to drill at an angle and the bit wonders off from the screw head resulting in a burr, and sometimes a non-flush application.

I've seen this problem happen mainly on 10-24 screws going into 10-24 inserts.  Material thickness of the plate varies from .125" - .375"

I'm not sure why the inserts collapse evenly in some instances and unevenly in others (though I have some theories).  Hope to hear from you.  Thanks.




Industrial & Systems Engineer Six Sigma & Lean Design


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Re: Insert
Re: Insert -- Kubtan Post Reply Top of thread Forum
Posted by: RandyKimball
Barney
04/21/2004, 19:02:50

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Sorry, but I'm confused.
Is the screw a self drilling screw ...or are you screwing a screw into a threaded insert?
Is it a punched in insert? Is it a squeezed insert of some kind? Is it a cherry type insert? Is is an insert with both inside and outside threads?
These questions bring up intirely different answers... ok?
Please provide more detail so I can try to help.

But... my first instinct is that you are not getting something square. For example, there are special holders something like the old drafting machines, that are designed to hold screw guns square. Actually they have their own screw guns already on them. You can pruchase them from most fastener providers.
Thank you,
-randy-




The worst suggestion of you lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

Modified by RandyKimball at Wed, Apr 21, 2004, 19:08:10

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Re: Insert
Re: Re: Insert -- RandyKimball Post Reply Top of thread Forum
Posted by: Kubtan

04/22/2004, 09:11:27

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Randy, thanks for the reply.

We're driving a screw into a nutsert that is compressed into a drilled hole, using a nutsert gun.  The nutsert has internal threads.

We don't have a holder to keep the screwguns square.  Our process, unfortunately, isn't conducive for a holding device like the drafting type you mentioned.

One theory I have is whether burrs on the other side of the drilled hole is causing the nutsert to collapse unevenly. Operators don't do any hole cleaning prior to nutsert installation.

I hope this helps clarify the issue.




Industrial & Systems Engineer Six Sigma & Lean Design


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Re: Insert
Re: Re: Insert -- Kubtan Post Reply Top of thread Forum
Posted by: RandyKimball
Barney
04/22/2004, 18:36:14

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You may be very correct. When you install a "nutsert" you should break the edge of the entry hole and if it clamps you should also break the back (or inside) edge as well.

A few of helpful ideas:

There are tools that have been nick named "clothes pin tools". These will break the leading and trailing edges of a hole with a screw gun in just a few revs., very effective, quick and inexpensive.

There are drills that will break the leading edge as they complete the depth by having a counter sink top on them. If you use one of these be sure to use a depth stop in conjunction.

The holes must be square to the face. There are ways to accomplish that.

Also the tool I was calling a "drafting type thing" simply holds the tool square anywhere inside of a three dimensional area.

I hope I have helped.

-randy-




The worst suggestion of you lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.


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