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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?
You've convinced me. Kroil it is.
https://www.amazon.com/Kano-Aerokroil-Penetrating-aerosol-AEROKROIL/dp/B000F09CEA/
EZ out, eh? That will probably be my last resort if none of these other great suggestions work.
Much appreciated!
Thank you. I'll make sure to do that.
BINGO...
Damn, I love this place. You guys are a wealth of information. I'll try it!
Great reference. Thanks!
Damn, I love this place. You guys are a wealth of information. I’ll try it!
...
The key is to break the rust. A quick tap that shocks the rust can work better than a whole lot of torque.
The homos at DU don’t know any of this stuff.
The screws hold two blocks together by means of a solid tube which separates the blocks about eight to ten inches apart. The neoprene feed roller (containing the shaft) is between the blocks.
There is a mirror set of screws on the opposing block that I'll have to also remove once I get the shaft and roller out of the main assembly.
“PB blaster or ATF and acetone.
soak and tap on them for a good while, leave over night.
Aluminium is soft and galls easily jaming them, worse than
stainless steel. When you put them in use a good anti-seize
and you won’t have this problem.”
In my over 50 years of wrenching, these two are the very best. First try PB Blaster - made specifically (unlike WD-40) to break loose frozen things. If that doesn’t work, a 50/50 mix of ATF and acetone (mix & let set for a few, then mix again before applying).
These work especially well on frozen pistons in engines........
beat it with a hammer and if that doesn’t work, try swearing at it.
Steel screws into Aluminum + time = chemical bond, no?. Do any of these penetrating oils actually affect the bond? It seems unlikely. But, maybe they keep the bond areas from reforming if one can gradually break some free?
The 50-50 mixture of ATF and Acetone is interesting too. The acetone would flash off quickly (unless it gets down into the threads.) Maybe it “wicks” the best? Slowing flash-off may be at the heart of mixes also containing mineral spirits or turpentine. I would wonder if xylene might not work well, to mix with ATF? Xylene has a slightly “oily” characteristic to it, to begin with.
BTW, PB Blaster should be available at Wally World, Home Depot, Menards, Lowes, and many hardware stores and farm supply stores.
Yes, Mouse Milk is one of the highest rated bolt looseners out there. Thanks for the link!
Heat then take a can of Air duster, turn upside down an freeze it , turn it out.....
A number of methods are used with success for removal on each of these methods...What works on the first one may not work on the 2nd or 3rd one...One thing I have done on numerous cases is to drill the head of the flathead screw using a drill the same diameter as the screw...Done right, this will pop the head of the screw off...If off center use a slightly larger drill to go back in the hole...The idea is to remove the head of the screw without damaging (too much) the chamferred surface that mates with the head of the screw...Drill only deep enough to pop this head off...
This will do 2 things...First one is that it will eliminate the pressure on the threads in the base...The second is that it will allow you to remove the piece bolted down...What will remain, depending on how thick the removed piece is, is the screw portion which will be extending out of the piece it is stuck in...This allows you to grab it with something to work it back and forth to get it out...
It the stud still will not move, the next option has almost always worked for me...
Set a quarter inch nut or five sixteenths over the exposed end of the protruding stud and have someone quickly put a weld tack inside the nut welding the nut to the stud...Wire welder with a quick burst so as not to get the stud to hot...
This give you a nut to put a wrench on to work the screw back and forth...
May sound like a lengthy process but it really isn't...Have had great success with this procedure with the 40 years of my experience as a Millwright...Just go slow and think about each maneuver as you move along...If this fails, all that's left is heli-coil time...And yes, there is nothing better or as good as Kroil (if the screws are vertical and hot horizontal...Good luck...
As has been suggested, an impact driver is a good option...Another suggested a chisel...I've used a center punch off center of the screw head pointed in the direction you want to go with good success...Just to get enough 'shock' to break it loose...
Using the method I just suggested, you can remove the bushings/rollers, or keep them cool during the procedure???
That's why I went into medicine. When your hand slips off the wrench your knuckles don't get scraped as much.
I thought about applying some heat as well, if whatever its in can take it. Expansion can help. Warm it, then hit it with your best lubricant. Wd40 is more of a degreaser.
It’s a busy thread. Thanks for following up to my replies.
Someone up-thread asked about backing strain on the bolts (e.g., two blocks of material bolted together.) If that’s the case, possible you could compress the fixture with clamps to relieve the pressure on the bolts? Or do you think it’s a matter of corrosion?
Good the bolts are intact.
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