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Old 11-20-2017, 12:31 AM
crystallographic crystallographic is offline
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Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 4,388
Default Removing Stuck Fasteners - Flush head screws

Project du jour :
Removing 1954 Dodge 1 ton brake drums, and the 3/8x16 flat head screws that are notoriously difficult to unscrew.

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Of course there are different methods for removing stuck/broken fasteners:
Drill off the heads - but you still have to remove the incarcerated stump remaining in the hub, after pulling off the drum.
Weld a stud or nut onto the head and use that to yard out the fastener - but you have to have a welder at hand, nearby, within reach.
Drill into the head and use a square-body hard tool to try to remove the fastener - great if you have a selection of sizes of them on hand, and even better if they work ...!
And ...
Using a punch, ground for offset taper and square on the point, to drive the screw around, like an impact wrench. We'll look at this method.
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Two out, and one to go.
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Punch has one side of the point ground back, offsetting the punch face, and the punch face is ground square and flat.
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You have to aim at the outer edge of the screw head - getting as much leverage as possible. (This method works on flush heads because the head diameter is larger than the shank diameter, giving rotational force/leverage that is greater than with other smaller, head size-to-shank size ratios.)
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Tool kit shown: L to R - special punch, screw driver with blade ground to fit screw slot, impact driver that was given up on, and the authoritative 16oz ball pein. (yes, my heavy blocks have carry handles on them)
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Holding the punch firmly and at the optimal angle to the expected direction of rotation - WHACK it.
5 or 6 times.
or 8 or 9.
Then change ends to spread out your "engraving."
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Screw driver finishes up.
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Shown here are the screw head, the punch end and the screwdriver blade ground square and even to match the screw slot.
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Here are the three screws removed by this method - Left was pretty easy, middle was stubborn, and right was pretty hard-headed.
But the driver fits well enough to use them all again ... if required.
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http://www.tinmantech.com

"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.

Last edited by crystallographic; 11-20-2017 at 12:36 AM.
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