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?
Re: Suggestions regarding the application of heat which you have reasonably rejected. Try dry ice which can be purchased from many supermarkets. The difference in the coefficients of thermal expansion or contraction is the operative force. You may recall that Indians split rocks by drilling holes and filling the holes with water soaked fibers which upon freezing expanded fractured the rock. Granted the fact that water expands upon freezing but the principle is the same.
The reverse action.
Don’t heat them, but cool them.
Try some compressed air on them to cool them down, shrink them a little and the Al should also open up a little, though the screw threads might tighten between one another, they should widen the tap dia.
I forgot plenty of your favorite penetrating oil applied multipke times over time.
A few drops of Pelosi ought to do it. It’s proven to loosen screws.
Use a soldering iron/gun to apply local heat cycling along with favorite penetrating oil. The hand held, hammer driven impact screw driver allow best control for not missing up the head as quickly.
Use a soldering iron/gun to apply local heat cycling along with favorite penetrating oil. The hand held, hammer driven impact screw driver allows best control for not messing up the head as quickly. Start with light blows.
Man up nancy
I agree with this: Kroil. It acts as penetrant better than a number of other choices, including PB Blaster.
Just freezing then?
Drill and replace.
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This should always be your last option. Common sense use of acetylene heat (torch) is always the way to go. I have not used the induction heat method but it is the new rave in heating ferrous metals. The problem with dissimilar metals (steel bolt and aluminum block) is the galvanic action (corrosion) that tends to occur between dissimilar metals that can bond the two metals together. You need to achieve expansion and contraction to break that bond.
WD40 is worthless.
Automatic transmission fluid and acetone?
Kroil is some fantastic stuff.
Lots of good suggestions here. Soak the heads three times a day with a good product for three days and then use the impact tool. I prefer this:
https://www.amazon.com/CRC-Knocker-Penetrating-Solvent-Aerosol/dp/B000LEVE00
Kroil is great stuff but the heat wrench is a miracle worker. I have a plumber’s torch of Acetalene that I use just for loosening stuck bolts and nuts
I don’t know why the designer would have specified self-tapping screws but that’s all I can think of as a possible cause.
I've used numerous on jobsites over the last 30+ years. Kroil is the best I've found.
PB Blaster is pretty good also.
Secondly, you have 2 very dissimilar metals. Steel and aluminum. They have different expansion rates. Maybe bring a little heat to bear. As they cool, break them loose.
Aerokroil isn’t widely as available on the shelf as others. I’ve seen it a few places. Try an industrial supply, box store, or large hardware outfit. Some Walmarts even carry it.
PB Blaster is available in most stores.
I haven’t used WD-40 in decades after I found this;
http://www.acehardware.com/product/index.jsp?productId=21099766.
Slick 50 One Lube has never failed to break anything loose for me yet. Not as quick as Aerokroil, but it’s only one third the price.
what he said.
Damn, I love this place. You guys are a wealth of information. I’ll try it
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Never thought this cerebral crowd would be so hands on mechanically skilled. I’m saving this thread for reference when I’m confronted with my next frozen nut or bolt nightmare.
Sharpen a pristine point on a small center punch or prick punch and drive the punch into the face of the allen head about half way in between the outside of the hex and the edge of the fastener.
Drive the punch at a 45 degree angle on the right side of the face (to reverse) to rotate the fastener out.
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