PPRuNe Forums - View Single Post - 737NGs have cracked 'pickle forks' after finding several in the jets.
Old 29th Sep 2019, 15:15
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Grebe
 
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Originally Posted by WingNut60
Is the sleeve of the same material as the parent metal?
Is the sleeve effectively swaged into place and then reamed, rather than the parent metal?

I have seen something similar using a roller reamer. That is, a process that just swages the parent metal to size.
But have never encountered use of a sleeve.
Note! Not to be confused with roller reamers as used in oil drilling.

Just interested in the process.

RE sleeve- no the sleeve is SPLIT and partially rolled together and is typically lubricated with a dry lube, and after expansion simply falls out or is easily removed. Look up the ( at least in Boeing ) the term ' coldworking ' and the firm in tukwilla called Fatigue Technology for more details.Fatigue Technology

401 Andover Park E, Tukwila, WA 98188, United States

They are a few blocks from Southcenter. Little known fact - one of the owners- perhaps now deceased was Burke Gibson-


Since the sleeves are NOT reuseable, and since they held some - but not all of the patents on the tooling ( pullers and certain adaptors ) they made- making a boatload of $$$.

And Lou Champoux was really more than a consultant - he was the inventor.

And to add or forestall the next ' logical' question re splt sleeve. Initially, Lou tried to use a spiral split sleeve due to concerns re a straight axial 'line' in the coldworked hole being a discontinut in the stress pattern. Almost impossible to make. So a straight simple split was tried- then the question was would the location of the axial ' line ' affect the load pattern and fatigue results ? After bucu tests the answer was nope.

By the way a large mandrel ( 1 inch approx ) lubricated with cetyl alchol as I recall has been used/tested to coldwork bolt holes in railroad tracks to improve fatigue life.

Last edited by Grebe; 29th Sep 2019 at 19:56. Reason: Add details re split sleeve to get back on thread track
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