Loctite

Discussion in 'Gunsmithing' started by HeskethPritchard, Oct 15, 2007.

  1. HeskethPritchard

    HeskethPritchard Well-Known Member

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    Guys

    I tried to take my stock off at the weekend and damn near destroyed my front screw trying to get it out, we had some serious screw drivers on the job and it wouldn't budge!!

    I made a few calls and found a guy who thought he could help me so off I trotted, rifle under my arm and THANKFULLY he managed to get it out. The last G'smith had loctite'd the screw in. The Loctite was a chocolate brown in colour although I cannot be certain if the colour had changed over the period it has been in situ and all the threads were covered in the stuff.

    I have three questions that I need your help on:

    1. Do I need to use loctite? If so what colour or code do I use?

    2. How do I get the Loctite off the threads and out of the threads in the hole?

    3. I thought you were only supposed to torque up the screws to 85ft/lbs is this correct?

    Any help would be appreciated.

    Thanks in advance.

    HP
     
  2. James Jones

    James Jones Well-Known Member

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    It sounds like the previous smith used red loctite which is the permanent type and generaly not ever needed with properly fitted parts. The red will turn color after time and with contact with oils and some solvents.

    Q) should you use loctite?
    A) yes one some parts like scope base screws , barrel threaded to action
    and any other parts that you don't want to come loose unless you
    want them off and in these applications only BLUE loctite is needed

    Q) how to remove red loctite ?
    A) the permanent (red) loctite will break down with heat , about 450deg
    also vibration will break it down and cause to "suger" making it easier
    to remove. for yourm action I woild suggest using a tap to chase the
    threads , NOT A CLEAN BOLT !! a bolt will only ruin the threads on
    both the action and bolt , it need to be cut out with a tap. You can
    use a small torch and heat up the bolt a little and the loctite can be
    removed with a wire wheel or small blade it you don't have a die nut

    Q) action screws touqued to 85ft/lbs ????
    A) 85 foot pounds NO , 85 inch pounds maybe , I personaly use 60 inch
    pounds. I don't think that 85 would be needed unless your bedding
    is bad and it takes that much to force the action into the stock and
    that is not going to be dood for accuracy.

    Red loctite is for permanent applications and takes moderate heat to remove like I mentioned around 450degs , it will also break down over time with repeated shock and vibration
    Blue loctite is the removable type and is good for applications that you want the screw their till you forcefully remove it.
    Green loctite is also permanent and is used to holt things that have already been fitted together as it will "wick" into the small gap left and is also used for a cylinderical locker as is used for press fit bearings
     

  3. HeskethPritchard

    HeskethPritchard Well-Known Member

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    James

    Many thanks for the advice so far. The bolt hole, as I am sure you'll know is a tapped hole in the receiver that ends and (as I haven't used a tap since high school) I think a tap is slightly conical in shape how will it get it all out? I'm not an engineer so please treat me kindly. Is there a chemical application I can use?

    Can I re-use the current bolt? will the Loctite re-grip again?

    I really need my rifle, its hunting season and I have to order the screws from Finland and I can't have my rifle out of commission for at least a month unless I really need to.

    Thanks in advance.

    HP
     
  4. HeskethPritchard

    HeskethPritchard Well-Known Member

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    James

    I have also been given some loctite 221 it is coloured red and the data sheet says:

    PRODUCT DESCRIPTION
    LOCTITE® 221 is a one component, anaerobic material which has low
    strength for easy disassembly. It cures when confined in the absence of
    air between close fitting metal surfaces.
    TYPICAL APPLICATIONS
    Prevents loosening through vibration and leakage of threaded....

    Also:

    PERFORMANCE OF CURED MATERIAL
    (After 24 hours at 22‚C)
    Breakaway torque, MIL-S-46163, N.m.: 5 to 12
    Prevail torque, MIL-S-46163, N.m: 2 to 8
    Breakloose torque, DIN 54454, N.m: 9 to 21
    Maximum prevail torque, KIN 54454, N.m: 9 to 21
    Static shear strength, MIL-R-46082, N/mm2: 3 to 10
    Static shear strength, DIN 54452, N/mm2: 3 to 10
    N.B. Ranges are based on mean !2r values.

    Taking on board what you said about red Loctite being pernament is this ok to use or should I go for the blue stuff? Do you have a product code for it?

    Thanks

    HP
     
  5. specweldtom

    specweldtom Well-Known Member

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    HP; replace the slotted head action screws with socket heads when you can. I make my own by modifying commercially available 1/4" 28 tpi socket head stainless screws, but I think they come on some Weatherby's, so you may be able to get them from Weatherby.

    The 1/4" x 28 machine screw tap is not a tapered (conical) thread, but the starter tap is sometimes called a taper. You only need to run a 1/4 x 28 bottom tap into the blind hole in the recoil lug and then blow the hole out with compressed air to clean it up. No, the locktite won't re-set, but clean it off everything, and don't use locktite at all on the action screws. I use 65 to 85 inch lbs of torque on the socket head screws and they never come loose.

    Since you need to get your rifle going quickly, just clean the screws you have, and the holes with the tap if you can. If you can't get a tap in time, use a small pointed 90 deg pick to clean most of the locktite out the hole.Clean up the slots in the screw heads with a very small flat file so that they will hold a screwdriver bit, tighten them by feel, and test fire to see if your zero moved.

    Good luck, Tom
     
  6. James Jones

    James Jones Well-Known Member

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    you mentioned having to get screws from Finland so I assume that your gun is a Sako and in that case you can get some replacement screws from Brownells if yours are to badly messed up.
    as for getting the rest of loctite outof the action which is in a blind hole , meaning their is a bottom to it , you need to use a bottom tap. Bottom taps are desgined to be used after a starter tape (the tapered one) to cut the threads to the bottom of the hole. You don't have to use a tap to get it out , if you don't have access to one then I would either find a screw of the same pitch and thread , heat it up pretty hot and run it in the hole this will destroy the remaining locktite and allow it to be removed. Loctite will not "reset" to its origional stregth at least.

    I know that their are many differant strengths of loctite , I would just find one thats a removable strength and stick with that when loctite is needed and its not needed on your action screws.
     
  7. specweldtom

    specweldtom Well-Known Member

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    HP, James picked up on something I missed. You didn't say it was a Weatherby, and I didn't snap. Ordering screws from Finland should have made me ask. The process that I laid out is O.K., but the specifics, (thread pitch, source, etc) are out to lunch.

    My apologies, Tom
     
  8. HeskethPritchard

    HeskethPritchard Well-Known Member

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    James / Spec

    Many thanks for all the advice it is really appreciated. It is indeed a Sako.

    Decisions so far from me:

    1. I ain't gonna use Loctite at ALL on my baby.

    2. I will clean up the hole and the bolt/screw as you both described.

    3. I am desperately seeking new screws and I agree, I want socket heads, I reckon they will look even nicer when I fit the McMillan A5 I have ordered for her in jan or Feb next year.

    I'll take a look at Brownells to see if I can get them.

    Thanks guys
     
  9. James Jones

    James Jones Well-Known Member

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    Brownells has them , part number (319-414-270) they are made by Forster and are the slotted head screw like you have , B-Square may make a hex head screw like used on the Rem and such.
     
  10. NYLES

    NYLES Well-Known Member

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    1 more thing if the treads arnt buggered up I would use a cleaning tap...no need in recuttig threads just clean em out.

    Lets call it a thread chaser/cleaning tap...smallest I found was a 1/4-20.....it will recondition and clean threads but will not recut them.

    I know a regular ol bottom tap probably wont hurt a thing but its still another option.
     
    Last edited: Oct 17, 2007
  11. HeskethPritchard

    HeskethPritchard Well-Known Member

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    New set of screws on the way from Brownell's thanks guys.

    A final question: How easy/difficult is it to get the screws converted to allen key head?
     
  12. Wild_Bill

    Wild_Bill Well-Known Member

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    Screws and loctite

    Hi you're screws are metric not Imperial they are 6mm. you can use new countersunc screws with allen key heads from a bolt shop. If you need some I can get you some. We also have a Sako parts account so could get replacement Sako paarts for you.


    As for removing bolts locked in with loctite.

    Any strength can be removed with hot water . boil a kettle and poure over the bolts then heat the bolts and place the driver into the slot and give a tap with a hammer to help release them and they will come out. This works with all grades of loctite .


    Cheers Bill
    Australia
     
  13. HeskethPritchard

    HeskethPritchard Well-Known Member

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    Wild Bill

    Thanks very much, here in the UK we don't have these kind of shops anymore. Would you get me Qty 4 (1 set as spare) with the Allen Key heads, they need to match the current profile of being counter sunk. I have a set coming from Brownells to tide me over until I take delivery of my new McMillan A5 due to land here february time and I would like the new ones for that.

    Would you PM me with your details so I can get the funds to you, just let me know how much they cost.

    Many thanks again HP;)