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Thread: Oneway stronghold chuck frozen machine screw

  1. #1
    Join Date
    Mar 2016
    Location
    Lexington, KY
    Posts
    112

    Oneway stronghold chuck frozen machine screw

    I have used my Oneway Stronghold chuck for many years. I am always careful not to overtighten the hex screws when changing jaws. This week one of the screws would not come out. I doused it with WD 40 but partially stripped the hex head so that the supplied hex driver wouldn't work. Fortunately I had another 4mm T handled driver (thank you Harbor Freight!) which fit adequately. More WD 40, left it overnight. Tapped it with a punch and hammer, tried tightening and reverse tightening. Frozen! Bought PB blaster and soaked it several times. Nothing. Soaked it again and left it for 2 or 3 hours. And then it loosened! This may be old hat to those of you shade tree mechanics out there but I learned these lessons: 1) be more vigilant about tightening the screws in the future when securing chuck jaws; 2) PB blaster (I was very aware of the product but had never used it) is probably superior to WD 40 (which I have always used) for this sort of frozen screw/bolt situation; 3) patience is a virtue in this situation; 4) periodically examine the machine screws and discard any with 'rounding' of the hex recess just in case. Nothing very profound in all of this but I was so happy to have my chuck back as I needed it!

  2. #2
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    Good story! PB Blaster is my friend in shop and around the farm. I buy it by the gallon. I've soaked entire jacobs chucks, padlocks left outside too long, and other things by submerging, sometimes for weeks, removing from the bath occasionally to tap with a hammer.

    One thing to be absolutely sure of for hex socket set screws is to use the proper allen wrench, and a good quality one too! If not careful it's easy to grab a metric size or vice-versa that seems to fit but is a touch too small. I've also discovered the tolerances on cheap allen wrenches are often poor AND the steel may not be properly hardened and tempered - all contributing to rounding. When all else fails, I have resorted to grinding an oversized hex key to fit more snugly into a damaged socket. What's worse, all set screws are not created equal - some cheaper ones are poorly made and not properly hardened. You test what comes in a kit.

    Another thing that almost always works is the "fire wrench". If the mechanism will take the heat (and I don't know about the chuck), heating the metal with a torch will cause some expansion and often break loose a stubborn connection. In the shop I use propane or mapp gas; on bigger stuff the ox-acety torch (what they use in the muffler shops.)

    One more thing I learned years ago - never tighten a threaded connection without first lubricating the threads. Contrary to some popular opinion, this will not permit a properly tightened connector to loosen unintentionally. For larger bolts I use an anti-seize compound but for small machine screws and set screws I use a tiny smear of oil or silicone grease. Works for me.

    JKJ

    Quote Originally Posted by David Sloan View Post
    I have used my Oneway Stronghold chuck for many years. I am always careful not to overtighten the hex screws when changing jaws. This week one of the screws would not come out. I doused it with WD 40 but partially stripped the hex head so that the supplied hex driver wouldn't work. Fortunately I had another 4mm T handled driver (thank you Harbor Freight!) which fit adequately. More WD 40, left it overnight. Tapped it with a punch and hammer, tried tightening and reverse tightening. Frozen! Bought PB blaster and soaked it several times. Nothing. Soaked it again and left it for 2 or 3 hours. And then it loosened! This may be old hat to those of you shade tree mechanics out there but I learned these lessons: 1) be more vigilant about tightening the screws in the future when securing chuck jaws; 2) PB blaster (I was very aware of the product but had never used it) is probably superior to WD 40 (which I have always used) for this sort of frozen screw/bolt situation; 3) patience is a virtue in this situation; 4) periodically examine the machine screws and discard any with 'rounding' of the hex recess just in case. Nothing very profound in all of this but I was so happy to have my chuck back as I needed it!

  3. #3
    Join Date
    Mar 2016
    Location
    Lexington, KY
    Posts
    112
    Thanks for your helpful comments John. I was worried about taking a blowtorch to the chuck! That chuck as you know is expensive.But it sure is beautifully machined (and not made in China!) I do clean my chuck often and spray it with Boeshield T9 which helps lubricate the threads.

  4. #4
    Join Date
    Apr 2018
    Location
    Cambridge Vermont
    Posts
    2,282
    I don't think I used the Allen Wrench that came with my Vicmarc chuck. It's somewhere but I use BondHus brand T-handle Allen wrenches. Made in the US with a lifetime warranty. You can get a set with the larger ones that have what is called a ball driver or just a straight hex shaped tip. I have seen people break off the ball driver but only on over tightened screws. I've never personally done it. Buy yourself a good quality set before the Harbor Freight set (I have some of them too) lets you down.

  5. #5
    Put a dab of Never Sieze on the screw wnen installing the jaws.

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