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Old 11-20-2017, 12:31 AM
crystallographic crystallographic is offline
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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.

P1040532 copy.jpg
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.
P1040535 copy.jpg
Two out, and one to go.
P1040536 copy.jpg
Punch has one side of the point ground back, offsetting the punch face, and the punch face is ground square and flat.
P1040537 copy.jpg
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.)
P1040538 copy.jpg
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)
P1040539 copy.jpg
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."
P1040539 copy.jpg
Screw driver finishes up.
P1040543 copy.jpg
Shown here are the screw head, the punch end and the screwdriver blade ground square and even to match the screw slot.
P1040544 copy.jpg
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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Last edited by crystallographic; 11-20-2017 at 12:36 AM.
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Old 11-20-2017, 01:36 AM
nonyorrick nonyorrick is offline
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Default Heat

Thanks, Kent, for addressing this issue. I often run into it, also (or in particular) with the screws on starters and dynamos. Removing them is often destructive, but if you heat them with the oxy welder they come out easily, and without damage. Of course you have to be quick in order not to burn the interior, but it works very well for me and it saves me hours of chasing screw dimensions which ore long out of production. And in your case, the welding bottles would be mobile enough to be carried wherever you need them.
Regards,
Patrick
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Old 11-20-2017, 05:56 AM
Larry4406 Larry4406 is offline
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I have had to resort to similar methods to remove stuck fasteners. Have not offset ground the punch tip though, may have to think about that one for the next time.

Restoring the truck?
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Old 11-20-2017, 10:01 AM
route56wingnut route56wingnut is offline
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I have mostly eliminated stuck fasteners with I bit that is used on an air chisel it has either a 3/8 drive or 1/2" drive so as to use Phillips or straight bit sockets with. It also has a feature that allows a 3/4" wrench to go on. This allows the user to put slight pressure with the wrench in the direction for removal while the hammer action is not only vibrating the rust loose but also driving the driver deep into the slot or Phillips recess so that it won't slip out.
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Old 11-20-2017, 10:55 AM
crystallographic crystallographic is offline
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Quote:
Originally Posted by nonyorrick View Post
Thanks, Kent, for addressing this issue. I often run into it, also (or in particular) with the screws on starters and dynamos. Removing them is often destructive, but if you heat them with the oxy welder they come out easily, and without damage. Of course you have to be quick in order not to burn the interior, but it works very well for me and it saves me hours of chasing screw dimensions which ore long out of production. And in your case, the welding bottles would be mobile enough to be carried wherever you need them.
Regards,
Patrick
Thank you Patrick - Yes, I use the heat method on many other types of situations, but in these particular cases the thermal mass of the surrounding components far out-soaks my #5 O/A tip inputs .....
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Old 11-20-2017, 11:02 AM
crystallographic crystallographic is offline
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Quote:
Originally Posted by Larry4406 View Post
I have had to resort to similar methods to remove stuck fasteners. Have not offset ground the punch tip though, may have to think about that one for the next time.

Restoring the truck?
Hi Larry,
I finally had to customize this punch for one difficult job and then just left it this way because it worked so much better at confining the impact area to the "shelf" of the slot ..... No, not a resto, but I need a dependable plow / lift / drag 4wd rig, so I am "freshening up" the obvious deficiencies - like the brake pedal that suddenly snoozed down onto the floor board....
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Old 11-20-2017, 11:08 AM
crystallographic crystallographic is offline
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Quote:
Originally Posted by route56wingnut View Post
I have mostly eliminated stuck fasteners with I bit that is used on an air chisel it has either a 3/8 drive or 1/2" drive so as to use Phillips or straight bit sockets with. It also has a feature that allows a 3/4" wrench to go on. This allows the user to put slight pressure with the wrench in the direction for removal while the hammer action is not only vibrating the rust loose but also driving the driver deep into the slot or Phillips recess so that it won't slip out.
Hi Dan,
I used to do that too, but then I got an old Skil 1/2" drive pneu rattle wrench with impact bits that I grind to fit. I can lean really hard on that gun and then tap-tap-tap on the slow trigger setting and walk them out - quicker than the hub can turn .... but I am saving that one for the next installment of "Stuck Fasteners."
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Old 11-20-2017, 12:47 PM
sblack sblack is offline
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can you show a clear picture of the tip of the modified punch? The description "offset taper" is not registering in my tiny brain.
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Old 11-20-2017, 02:45 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by sblack View Post
can you show a clear picture of the tip of the modified punch? The description "offset taper" is not registering in my tiny brain.
P1040547.jpg
P1040548.jpg
P1040550.jpg
Dimensions = contact area of accessible portion of the side of screw slot.
1 sq mm or 2 sq mm, or ..... etc.

This punch needs to be dressed again now that I see the close-ups, as it has seen some pounding since it was last dressed.
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Last edited by crystallographic; 11-20-2017 at 02:48 PM.
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Old 11-20-2017, 04:23 PM
lots2learn lots2learn is offline
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Most metal shapers have a rivet gun or air chisel. These work better than an impact driver for me.

https://www.browntool.com/Default.as...4&ProductID=96
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