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Thread insert strength


Edgar

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It appears that an M10 bolt hole on the right rear side of the transmission, where the rear frame bolts on is in bad shape. I'm going to be looking at it later today. I've used Time-Serts before and found them to work well. The bolt requires 47 nm / 35 Flb. Will inserts work with those forces?

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In one word.

Yes.

 

And in many more words direct from the source...

 

Q. What are the torque and pull out specifications for the TIME-SERT?

 

A.TIME-SERT makes no claims on torque specs or pullout. The reason being there are many factors that can determine the end result of the insert thread strength. One being the installation process.

 

1)Was the insert actually installed correctly and square to the hole? This would have a huge effect on the outcome of the torque specification. Along with what type of material being inserted, plastics will not have the same torque values as aluminum's, steels, or cast irons. Another thing to keep in mind is the length of the insert. Inserts must match the length of the bolt threading into the hole. Too short of an insert length could result in thread failure.

 

TIME-SERT will state that if the thread repair is done correctly and with the proper length of insert used for the application, the result should be a hole that will match the original torque specification of the hole.

 

Customers have found in their own testing data that TIME-SERT's have exceeded their expectations. Many of our larger customers will test TIME-SERT's before placing them in critical applications and find excellent results.

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look for "king serts" called so because of the pins you drive in when you put the insert in, this is the best thing to fix a stripped hole because you are putting a metal insert in place of a stripped aluminum hole. i have used them from time to time and will everytime i must drill out a broken bolt or stripped hole.cost alittle but you'll have real piece of mind for it.

joel

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Danny caddyshack Noonan

Trade name for kingserts is Keensert. Mcmaster carries them under thread repair...key locking insert (not helical). These exist in most pieces of aerospace aluminum requiring a threaded hole. Helicoils are less common. Very strong, get stainless. Ignore any squeemish phobias over stainless in aluminum as the surface area of the tranny is much much larger than that of the stainless so there are no worries over galvanic corrosion.

Unless there is an existing locking thread in the hole, to not get locking element as you won't be able to determine the correct torque. Run-in torque with these must be characterized and measured prior to final torque.

 

Very important to get them in square per prior post.

 

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Assuming you presently have marginal situation, use a Heli-coil insert since it requires less of the supporting material to be drilled out than any other threaded insert.

 

You might also consider the possibilities of extending the insert, and the insert thread depth, to near the bottom of the present hole by using a bottoming helicoil tap too. Then put in a longer bolt to reduce the shear stress on the parent material.

 

Perpendicularity is very important too.

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