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Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
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Posted by: William Thorn

03/21/2006, 15:49:58

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A question came up at work regarding the merits of various threaded inserts. I wanted some additional input.

Here is the situation, we are a manufacturer that utilizes a lot of alumininum tubing and plate. Plate thicknesses range from .25" to 2.25" thick. We always use Grade 8 threaded fasteners to attach the aluminum plate. Our hardware is almost always steel with an organic coating (Magni) to prevent corrosion. We would like the most positive connection between the aluminum plate and the members to which it is joined.

What are the advantages of Helicoil vs. Keensert vs. Microdot inserts? When should one be used over the other? Any and all information about the topic is greatly appreciated.








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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? Smile
Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- William Thorn Post Reply Top of thread Forum
Posted by: Marky

03/22/2006, 11:26:34

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I've always been a fan of Helicoil Inserts. I find that they're more commonly used. I spec them on a drawing and the shop never has a problem.

All 3 seem equal in form, fit and function.

Hope this helps

Marky








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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- William Thorn Post Reply Top of thread Forum
Posted by: randykimball

03/21/2006, 23:31:32

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The best insert.... well I have a strong opinion.

In such a situation I, by far, prefer the threaded cherry rivets.

You stick them through the aluminum and there is a tool that squeezes them so that there is a head one one side and a flare on the other. They are made of good meterial and are corrosion prevent coated already. There are pneumatic guns to apply them and also less expensive hand squeeze guns. The inserts thread onto the tool and then are inserted into the hole. After the crimp/flare the tool unthreads itself. "They ain't go'n no where". They fit something like a molybolt.

These are VERY popular in aircraft construction.

/←randy→/





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Modified by randykimball at Tue, Mar 21, 2006, 23:33:48


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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
Re: Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- randykimball Post Reply Top of thread Forum
Posted by: randykimball

03/22/2006, 23:14:05

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oops.. my bad..
For some reason I got into my head we were talking about thin aluminum...

I like coil inserts. In aluminum I prefer the longer ones to gain more thread depth when there is enough meat to use them.
I haven't had problems with coil inserts when applied correctly with the best tools. I've been known to apply them with XPD (zink chromate primer) in the hole to make them set up and stay put. Not too much, just enough to seal the contact between the outer coil form and the threaded hole. This improves the corrosion resistance as well.
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The worst suggestion of your 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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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
Re: Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- randykimball Post Reply Top of thread Forum
Posted by: William Thorn

03/22/2006, 08:48:22

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Thanks for the suggestion. I probably should have specified that the smallest diameter bolt we currently use is 3/8" (very high forces are involved in our application). Most threaded fasteners for the 2" thick aluminum are actually 1/2" in diameter. In addition, customer requirements are for as few fasteners as possible. From my limited experience with Cherry threaded rivets, this would not be the best application of them.







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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
Re: Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- William Thorn Post Reply Top of thread Forum
Posted by: WhiteTiger

03/22/2006, 20:30:26

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Keensert, hands down for me. No wire coil to spring free and back out with the bolt, solid insert full depth and staked in place.

They may be harder to replace, but they are far less likely to need replacement in the first place than the wire coil style.

Oh, one other consideration in aluminum applications: I've seen the wire coils "roll" and strip both the bolt and the inserted hole when over torqued. Can't recall ever seeing a torque failure with the keensert solids or any of the clones unless they had been seated way too deep.


Tiger








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Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot?
Re: Re: Threaded Inserts for Aluminum - Helicoil vs. Keensert vs. Microdot? -- WhiteTiger Post Reply Top of thread Forum
Posted by: Kelly_Bramble

03/23/2006, 07:42:05

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I know that most manufacturing organizations like any of the "tang-less" type threaded inserts. This is because they can remove and replace these types easy if there is a problem.

Additionally, this eleminates any quality or other problems which might occur when the tang is left in the installation or breaks off after the product is put in service.






Modified by Kelly_Bramble at Thu, Mar 23, 2006, 07:47:57


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