Prop grub screw removal

[frilaens]

Hallo,

My folding prop has a grub screw with a hex tightener that stops the locking nut turning. I have over-tightened this and now I can't undo it; the hex key turns in the hole. Anyone suggest a way to remove it? I have thought about using the next size up hex key and filing down the faces slightly, or tapping it in with a hammer.

Andy

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[dickh]

That is an option you suggest, also try some heat on it as you try and unscrew it. Make sure you use a good quality hex wrench - some cheap ones are crap!
Finally you'll have to drill it out......
God Luck!!

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[Talbot]

no dont do that - you will make it even more difficult to undo next time. I had this problem on a bike, and was really desparing when my friendly mechanic introduced me to an impact drill that would take special hex keys. Note this is a specialist machine and not your average B&D set on hammer /forums/images/icons/smile.gif This tonked away for a few seconds and then the screw came undone easy as that. So talk to a well stocked garage with a friendly mechanic.

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[Heckler]

the answer here is patience and some mechanical empathy, you have either used the wrong size key and worn both the screw and the key so that they are both knackered or if you are sure that you used the right sized key have worn the screw beyond redemption. allen screws are as hard as hell, cheap keys are not. usually the key knackers up first. check and double check that you have the right size key, they are measured across the flats, paint etc can mislead you, they can be millimetre or unified. check your key set and see what they are measured in, most these days are millimetre, they need to be a snug fit, blow torch the screw to clean any crud and also to aid in removal, try and get a snug fitting key in and tap judiciously, the key is heat and shock loads, a centre punch or drift to tap the screw helps, a little and a lot, you shouldnt be able to file an allen key, it should be too hard, if you can tap in a bigger size, do so, if the screw really is rounded you will have to drill out, screfix sell some really good drills now with titanium hardning, use on a very very slow speed.
impact wrenches are NOT the answer as in the other post, they only work if you have good flats to grip on.
heat, ingenuity and patience and by the way to undo it turn to the left! not joking have actually pulled someone out of the mire who was turning the wrong way!
stu

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[robind]

If you have to drill it out use a left hand drill bit, (yes" anti clockwise) chances are that the bolt will come loose before the drill has gone any way to reaming it out. (Oh! and use a reversible drill too of course!)

Rob

<hr width=100% size=1><A target="_blank" HREF=http://www.rejuvanu.com>RejuVanu</A>

 

[vyv_cox]

Good practical advice as usual. I recently bought a set of Allen keys from a local DIY shop for a quick job at home. They were as soft as butter and rounded immediately I put any force on them. Beware keys that look shiny black, they are painted to look like the real thing. Correctly heat-treated keys are dull black and, as Stu says, it is almost impossible to cut them with a hacksaw or file them.

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[Omatako]

By now you have probably sorted the problem but maybe this will help.
Depending on the size of the grub screw (hopefully it's 8mm or bigger), a small hole can be drilled and a gadget called an "eezy-out" can be used. This is a tapered hardened screw thingy with a left hand thread which is turned into the new hole and tightens as it enters. Unless the screw is really tight, it will turn it out. A tip though, don't be tempted to drill a bigger-than-required hole because if the wall thickness of the screw becomes too thin, the eezy-out will simply spread the walls as it enters and make things tighter than they already are.
Also be aware that if you're working with a stainless screw in a stainless hole, it could be "galled" in which case there is only one solution, drill it out.

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