Screw Lock





Introduction: Screw Lock

Problem: "to have a screw losse"... :-)
Solution: Two component glue.

Step 1: Material

Two component glue

Note: Glue is here already mixed up. Only about 1cm is needed.

Step 2: Do It

So put some glue around the screw.

You can also see the bicycle pedal.

The problem was, that the screw on the bicycle pedal alway opened by itself. After ride the bicycle for a while, the screw was open.

I know there is a special like oil fixing screw or the like. But this did not helped that much.

WARNING: You should only use this method with the two component glue on parts of the bicycle which is not critical to damage something or somewhere which it can be VERY DANGEROUS if it breaks!



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    10 Discussions

    Helmut118 Have used the lady's discarded finger nail polish as cheap lock-tight. Old electronics's tech trick to secure fasteners. Color is not important unless your into aesthetics ;-) Gday

    1 reply

    Fingernail polish ranks right up there with duct tape & baling wire. Aside from glue solutions, it makes a very decent touch-up paint for vehicles, and comes in almost unlimited colors (including clear). I keep a bunch of it around, and that little built-in brush means that it's likely to be used more often since everything's right there. The fingernail polish is very tough in outdoor use. I mark all my positive battery clamps & posts with a red "+" and mark part numbers for oil filters, air filters & belts under the hood with any color handy. And it can always come off with acetone, if need be. A friend of mine marks his oil & air filters with the date & mileage before he installls them - a good idea, but I can't remember to do it. Used fingernail polish can be found for almost nothing at garage or yard sales, though if you're a big burly guy you might get some peculiar looks from people.

    Unfortunaely , the issue could well be something other than the thread (internal, external, or both); if the crank arm has not been properly installed and wrenched on, there is a strong possibility of the tapered square beginning to round slightly. The upshot of this, in the event of only slight damage, is the the crank arm will almost invariably come loose, but each time it does come loose, the tapered square hole becomes increasingly rounded. In the longer term, you have to replace the crank arm, as no amount of reefing on a wrench is ever going to tighten the thing - because the crank arm's become a different thing than properly belongs in that location. When you remove a tapered-square crank arm, from either side, and you re-install it, best practice is to use a torque wrench to tighten the nut (more often lately, bolt), then take the bicycle for a short ride (around the block, say), then come back and re-tighten the nut (or bolt, as the case may be). If you do not have a torque wrench, and/or can't (be bothered to) look up the appropriate torque value and apply it, then the first tightening should be 'to a modest grunt'. The second tightening, or re-tightening, should be perhaps a sixth to a quarter turn beyond where you begin.

    Aside from the crank hole getting deformed by being pedaled loose, have you been making sure to torque the bolt down hard enough? Park Tool has a list (at the bottom) and it can range from 300-480 in.-lb.!
    Torque specs

    How long has it lasted like that? I find that when a crank gets too loose, and it wears away some of the square peg/ square hole.. Its too late.. I've tried loctite on these occasions, but with only a temporary result.

    From my medium-poor german translation, that's a two-part , 5 min epoxy... Nice, quick solution to an annoying problem. WONDERFUL photography that illustrates the problem well. Ein gut gemachtes Projekt. 'loctite 243 Threadlocker' Oil Resistant/Medium Strength is the stuff we'd use in these here parts. For best results, let it set and cure for 24 hours.... though 2 hours, on a mild steel will suffice, since it's only a mild action attempting to unscrew the bolt. It appears , in the first picture, of the last step, that the threads of the bolt have slightly stripped, or worn.... If this is true, than loctite would help a bit, but a more permanent solution is needed. Fixmaster® Steel Liquid is the loctite product for this. JB Weld would also work well.... and for short term use, any 2-part epoxt, such as the OP used would work well. In effect what he did was rebuild the internal threading on the crank, using the epoxy. With the added benifit of adhesion, limiting the rate of furute failure. Eventually, you'll want to replace the bolt, mabey even the whole crank assembly. In the mean time, anyone else doing this, while you have the crank arm off, take the time to lube your bearings while you're at it ;-) ESPECIALLY if you're running open-to-all-creation ball berings like Michi.

    Just looks like a 2 part epoxy but i could very well be wrong.. If it was really a problem i would of used loctite. The threads should be clean cause there was a bolt in there, it's not like it was some open hole that was exposed for years the the elements. Red loctite is stronger then Blue Loctite. I would of used Blue Loctite in this situation

    What type of glue is that? I can see it's a two part -- but I myself have several types of two part adhesives :P Just curious as I am not fluent in that language :)

    Red or Blue loctite is what you're talking about. It wouldn't have worked for this unless you made sure the bolt and internal threading was really, really clean.

    1 reply

    Hmm... yes I know "loctite". But I meant(?) something different. Loctite is much more "harder" then this Oel-Like thing. (Anyway, this simple Two-Component glue worked for me.)