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  1. #1
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    Default [HELP] Stubborn screw thread removal

    Just got an a&a Bench grinder and multi-tool seperately and am in the process of removing one side to attach the multi tool but the screw attaching the guard is stuck and really soft, I'm worried I'll strip the head before it budges, any tips for these tough nuts?

  2. #2
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    Welcome to the forum typicalabc,

    Theres a chance there may be some loctite or similar product holding the screw threads,

    If you apply some local moderate heat-too hot to touch might be about right- to the screw and try to unscrew it while hot.

    Hang on though, some of the blokes might be along with a better idea.

    Grahame

  3. #3
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    I ended up stripping the head completely trying to remove the screw with an impact driver but I wrestled it out with liberal amounts of wd-40 and snub nose pliers.

    Quote Originally Posted by Grahame Collins View Post
    Theres a chance there may be some loctite or similar product holding the screw threads,

    If you apply some local moderate heat-too hot to touch might be about right- to the screw and try to unscrew it while hot.
    I'm shy of using heat near electronics so that never crossed my mind, I'll keep that in mind for next time. Thanks!

  4. #4
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    Any idea on thread size of screw? If you have to resort to an easy out type thing, then try an allen key instead. Select the drill size according to the across corners measurement of the allen key and choose a little smaller. Tap allen key in and the corners will grip better than any easy out.
    Nev.

  5. #5
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    If it's a phillips head screw, find your best fitting screwdriver, hold it into the head as firmly as you can (brace the grinder against something), and also hold as much rotational pressure as you think you can get away with, then give the handle of the screwdriver a couple of hits with a hammer (as though you're trying to drive the screwdriver into the head of the screw. Poor mans version of those spring loaded mechanical impact drivers. Can do similar things with allen keys, if you have a socket type driver (bit more difficult with a regular L shaped allen key to get the sort of solid blow on it you need). Can also do it with regular hex head bolts, but it only really works well if they have a head that incorporates a washer (otherwise all the shock from the hammer blow just goes into the housing and not the bolt).

  6. #6
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    Grahame is right heat it up and give it a whack with a small hammer with a screw driver in the screw then try and unscrew it . It's probably rusted in . It's amazing that rust can grip stronger than the steel .
    The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.

  7. #7
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    Quote Originally Posted by Jekyll and Hyde View Post
    Can also do it with regular hex head bolts, but it only really works well if they have a head that incorporates a washer (otherwise all the shock from the hammer blow just goes into the housing and not the bolt).

    In that situation use another nut as a spacer in the socket, to give clearance.
    Nev.

  8. #8
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    An old trick that really improves your chances of removing a tight screw is to put a small amount of valve grinding paste on the screwdriver tip. This dramatically increases the grip and reduces the possibility of stripping out screw heads.

    Try it and you will be amazed at the difference it makes.

  9. #9
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    blackburn vic
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    Assuming it is a cross head screw make sure you have the correct screwdriver. There is a considerable difference between "Phillips" and "Pozidrive" screws and their drivers.

    Roger

  10. #10
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    Use an old school impact driver ie the ones you hit with a hammer. The reasons screw aren't slotted in many applications and are instead hex etc is the slotted screws tend to cam out with force. An old school impact driver both hits it with a hammer (another separate trick to free an old fastener) AND torques it at the same time. They are still available cheaply

  11. #11
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    Small screws can sometimes take a lot of convincing to remove. Remember doing some repairs (needed new chain) to a self propelled mower my brother had. I actually broke an impact driver on the 5mm, I think it was, screws I had to remove from a cover over the axle.
    Nev.

  12. #12
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    Quote Originally Posted by Retromilling View Post
    It's probably rusted in.
    OP didn't say whether the grinder is new or old. I assumed new, but you might be right.

    I would also try a hammer type impact driver. However, make sure you have it set to undo the screw, not tighten it. The impact driver I have needs to be set to the desired direction of rotation and it's not obvious which way it's set for. Here's a video by one of our forum members:

    https://www.youtube.com/watch?v=cUSuSn_QZmk
    Chris

  13. #13
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    I recently watched a video where the poster recommended tightening a bolt a bit before trying to undo it. Just saying. You would have to be careful with a screw.

    Dean

  14. #14
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    And sometimes nothing will work and the screw head just mangles up or rips off. In the end you may have to drill the head off anyway , try an easy out but if no joy just drill it out an retap to a larger size screw .
    The volume of a pizza of thickness 'a' and radius 'z' is given by pi z z a.

  15. #15
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    If removing the screws fails with all mentioned techniques ( I think I did not see the "soak with penetrating oil" idea) and you need to drill out the old screw this might be some ideas:
    - There are left handed drill bits. Buy one the appropriate size and with some luck the screw comes loose when drilling out. Use the biggest size drill that is equal to or smaller then the tap drill size of the screw. There are also left handed NC starter drills which might do the same thing. These are not the well known centre drills ( I don't know if the latter exist left handed but I have never seen one) but rather sollid shanked bits with the same point angle as ordinary drill bits and a short flute.
    I have some sizes of both exactly for these occasions.
    (B.t.w. if it is a through hole using an ordinary drill might do the same by turning the screw out of the hole on the inside)
    - if you can fixture the machine properly, try centering the hole properly and drilling the hole to tapping size. The remaining threads should be possible to clean by picking them out with some effort.

    - if all else fails hopefully there is enough metal to drill to the next tapping size and use a bigger fastener (as mentioned above) or make a bushing and tap a new hole of the original size.

    Good luck, I hope you will succeed in a way that leaves the original hole in a usable state.
    Peter

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