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?
Thanks in advance.
Drill and replace.
You probably already did it, but I finally learned to tighten first and then loosen.
Kroil. It is a penetrant but superior to all others. Not cheap but it works where others don’t.
Torque them in the tightening direction momentarily then reverse torque with “impulse”. Repeat a few times as necessary.
I, too, use Kroil. Nothing like it.
Repeated thermal cycling. Impact extractors. Make sure not a lefthanded thread.
Try Kroil expesive and hard to find or Marvel Mystery Oil
Thanks, guys. I'll give that a try.
A blast from a propane torch or heat gun? The aluminum of the part should expand a bit faster than the steel of the screw, no? You might have to heat while exerting torque on the screws. If you don’t want top apply heat or think it might do damage, then get a block of scrap aluminum (or brass) and clamp it to your piece with no gap, you may be able to whack it with a medium hammer while applying torque to the screw but hitting the block, you won’t gall up the surface of your machine.
Thanks, but it would be easier for me to replace the whole assembly. I might do that, if I can't get the Allen screws out.
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.
A dremel and a nut cracker is all you need. Cut the nuts close to the threads and then snap them off. Takes some time but easy peasy. You could drill them. You could try PB Blaster overnight soaked and I mean soaked wrapped in shop rags. Sounds like you have bimetal corrosion.
Nuke it from Orbit...it’s the only way to be sure.
Try a little heat. They could be secured by loctite, or seized, either way some heat could break them loose.
Would I find that in a hardware store, or an automotive store? Much appreciated.
Correct on all three counts. You might also hit them by putting something into the allen wrench socket and hitting the end of them to break them loose (don't hit too hard) which is called "warming them up". The impact extractors would also do that for you. Also, think about the concept of reverse thread. Best wishes.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
