Posted on 03/12/2017 9:53:29 PM PDT by Windflier
I'm trying to replace a broken shaft in my sheet metal extrusion machine, but I've run into some machine screws that just will not budge.
They're 3/16th, Allen type, steel screws, mounted in an aluminum block. They have a patina of rust on them, and I already broke a new bit trying to bust the first one loose. I sprayed them all with WD-40, and gave it an hour or two to soak in, but still no go.
Anyone know of a better lubricating product, or some trick I can use to get these suckers to turn?
1) are the screws left-handed? (left to tighten)
2) if not, then “EZ-out’ kit the one you screwed up. On the ones you haven’t messed with, from autozone, there’s a catalyst product better than wd-40, called PB Blaster or Blaster Chemical Penetrating Oil.
Cut inch off the long end of allen wrench, put in screw and several firm blows with a hammer. Usually will make the difference.
Aerokroil.
Big Ed that’s a bit overkill (no pun intended) just use liquid wrench.
I thought of that, but put it out of my mind, as the repair instructions made no mention of it.
Others have suggested that I try tightening, then loosening. That should give me the answer, if they'll move.
Sounds like a flat head cap screw. Make sure you are using a quality allen wrench that is the correct size. Some cheaper made tools might not fit as well in the hex socket of the screw. Also, use a wrench with the shortest possible length—the farther the wrench sticks out of the socket, the greater the chance it will twist and break. When trying to turn the screw—push the wrench completely into the socket, and hold it there while applying torque—any misalignment can result in the wrench stripping out the screw.
If all else fails...get a left hand drill and drill out the screw. 23 years in a machine shop...pulled out a few stuck bolts and screws...
Tapping on the heads creates vibrations that pull the
soaking fluid into the joints of the threads, don’t be
in a hurry, work, then let sit, spray and repeat, leave
over night if you can. Trying to drill them and use an
ez-out may be the last resort but be sure to use the
correct size of drill and EZ-out. Good luck.
Make sure your allen wrench is the correct one and a
good solid fit. Tap on the wrench as you try turning it
too.
Thanks for the tip! I know right where to get that.
If you've already tried penetrating oil (not WD-40, real penetrating oil) you could try an impact screwdriver. If you ever worked on a motorcycle, you know all about them. The shock of impact combined with twisting action might break it loose.
Next I would try heat - just not too much. Aluminum and steel expand at different rates when heated. Try heating area around the screw with a propane torch, then applying ice or cold water to the screw itself.
All else fails, drill and easy-out. If you're careful and lucky you'll only have to replace the screws without having to fix the threaded holes .
Be sure to apply anti-sieze to new screws when reassembling, or they'll sieze up again.
Assuming you lost the hex hole... you can cut a groove with a hacksaw for a straight drive. Or grind flat edges on the screw heads for visegrip. If you lost the screw heads, you can drill and use an e-z out. I’ve had tough screws back out when reversing the drill (often because the screw head was gone and no longer forced against the surface.)
Good luck!
Heat and freeze, torch and can of freon or compressed air sprayed upside down. The use lube.
Auto parts will have a selection, maybe kroil, certainly
PB Blaster or you can mek your own with Automatic transmission fluid and 1/4 acetone.
ATF was developed to replace whale oil and is a very
good light lubricant.
We use it to clean weapons with, 1/4 ATF, 1/4 acetone,
1/4 mineral spirits, 1/4 terpentine.
It’s called “Ed’s RED” and works like a champ.
You can leave out the acetone and use it as a gun lubricant
or thicken it with lanoline to make a thicker mix.
Can't do that. The old shaft has neoprene feed rollers and plastic bushings on it. Heat could transfer through the aluminum block that holds it all together. Not safe in this application.
I may revisit your other suggestion, though. Thanks.
Does that label say ‘Aerokroil’?
Hard to read on my tablet.
Kroil, or maybe Ballistol. I’ve used both with success. The smell of Ballistol attracts women, too. They come in the room and say “what the hell is that smell?”
Try using a manual impact driver. If you haven’t seen one, it’s a reversible tool that you hit with a hammer. The force of the blow drives the bit into the screw and at the same time it turns the bit to remove the frozen screw. You can pick one up at Autozone for about $12.00.
Steel screws in aluminum is a good recipe for sacrificial or cathode / anode corrosion. The aluminum is sacrificial to the steel and will oxidize to protect the steel from further corrosion. This may not turn out well.
Try the Kroil or liquid wrench or PB Blaster and gentle patience. It is likely the threads in the aluminum will come out with the screws though and you’ll have to drill and tap new threads or use a helicoil to keep the same thread size.
They have started using aluminum on some garden hose fittings. Given just a little time those suckers will weld in place with corrosion.
I just pulled some cap screws off the tractor this afternoon to find corrosion in steel or steel. Always assemble with thread lube if you expect to take things apart.
Another vote for Kroil. I find that if Kroil won’t get something unstuck, the blue “wrench” is the only remaining option. Let it sit a while and give the fastener a gentle tap with something before you try to budge it. Steady pressure seems to get it moving eventually.
Any idea where I can purchase those? Auto parts store?
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