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    Bent / Splayed Power Tube Pins KT88 - Octal Tube Pin Straightener

    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

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    Post by aguaazul on Mon Mar 18, 2019 12:48 am

    I've got a bunch of nice power tubes, Chinese. A few have bent / splayed pins.
    I have a Pin Straightener for small preamp tubes, do they make one for big octal's that works well?

    The inter-webs suggest the 'BIC White' pen tube. Perhaps used for other reasons too... but I'm worried about damage.

    Should I use socket savers?

    Suggestions welcome.

    Thanks,

    Bluewater
    Peter W.
    Peter W.

    Posts : 1268
    Join date : 2016-08-07
    Location : Melrose Park, PA

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    Post by Peter W. on Mon Mar 18, 2019 7:28 am

    aguaazul wrote:I've got a bunch of nice power tubes, Chinese. A few have bent / splayed pins.
    I have a Pin Straightener for small preamp tubes, do they make one for big octal's that works well?

    The inter-webs suggest the 'BIC White' pen tube. Perhaps used for other reasons too... but I'm worried about damage.

    Should I use socket savers?

    Suggestions welcome.

    Thanks,

    Bluewater

    Effectively, there are no purpose-made 8-pin straighteners, or not since the 1940s, anyway. The issue being that the octal (and some novar) pins are composite, not solid wire. That is not to suggest that there is no solution.

    https://www.mscdirect.com/product/details/03123122

    A trick I learned from an old HAM, back in the day. This is an octal relay base that will do a decent job of straightening pins. AND, should you be making a breadboard model of an amp - it will allow you to make solderless connections. Handy. Be prepared to make the first adjustments with a pair of pliers - for which I keep an ancient pair of wire-bending/hose-clamp pliers with a hollow nose. It grips the entire pin, so no threat of a flat-spot.
    PeterCapo
    PeterCapo

    Posts : 678
    Join date : 2008-12-05

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    Post by PeterCapo on Mon Mar 18, 2019 5:08 pm

    Wonder if efforts to straighten the pins would be more successful if they were desoldered first.

    Seems like you'd need some kind of thin-walled but strong metal tube to slide over the pin and then straighten it.
    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

    Bent / Splayed Power Tube Pins KT88 - Octal Tube Pin Straightener  Empty Re: Bent / Splayed Power Tube Pins KT88 - Octal Tube Pin Straightener

    Post by aguaazul on Mon Mar 18, 2019 7:07 pm

    Peter W. wrote:
    aguaazul wrote:I've got a bunch of nice power tubes, Chinese. A few have bent / splayed pins.
    I have a Pin Straightener for small preamp tubes, do they make one for big octal's that works well?

    The inter-webs suggest the 'BIC White' pen tube. Perhaps used for other reasons too... but I'm worried about damage.

    Should I use socket savers?

    Suggestions welcome.

    Thanks,

    Bluewater

    Effectively, there are no purpose-made 8-pin straighteners, or not since the 1940s, anyway. The issue being that the octal (and some novar) pins are composite, not solid wire. That is not to suggest that there is no solution.

    https://www.mscdirect.com/product/details/03123122    

    A trick I learned from an old HAM, back in the day. This is an octal relay base that will do a decent job of straightening pins. AND, should you be making a breadboard model of an amp - it will allow you to make solderless connections. Handy. Be prepared to make the first adjustments with a pair of pliers - for which I keep an ancient pair of wire-bending/hose-clamp pliers with a hollow nose. It grips the entire pin, so no threat of a flat-spot.

    A tough hand held octal base is on it's way. Searching for the pliers seems to be a tough one. We'll keep looking.
    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

    Bent / Splayed Power Tube Pins KT88 - Octal Tube Pin Straightener  Empty Re: Bent / Splayed Power Tube Pins KT88 - Octal Tube Pin Straightener

    Post by aguaazul on Mon Mar 18, 2019 8:18 pm

    PeterCapo wrote:Wonder if efforts to straighten the pins would be more successful if they were desoldered first.

    Seems like you'd need some kind of thin-walled but strong metal tube to slide over the pin and then straighten it.

    I've never desoldered any tube pins before, I have a 6SN7 with a broken key way base I guess I could play with.

    The tube over the pin idea seems like a gentle way of moving them in just a little. Again, I'll take the 6SN7 into the hardware store to look for the correct tube for the tool.

    Thanks,

    Bluewater
    PeterCapo
    PeterCapo

    Posts : 678
    Join date : 2008-12-05

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    Post by PeterCapo on Mon Mar 18, 2019 8:23 pm

    If you can find a metal tube that works well for this, please let us know its specs, for example, inside diameter, outside diameter, what kind of material it's made of... if that's possible.
    Peter W.
    Peter W.

    Posts : 1268
    Join date : 2016-08-07
    Location : Melrose Park, PA

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    Post by Peter W. on Tue Mar 19, 2019 7:35 am

    PeterCapo wrote:Wonder if efforts to straighten the pins would be more successful if they were desoldered first.

    Seems like you'd need some kind of thin-walled but strong metal tube to slide over the pin and then straighten it.

    The typical octal pin is either a rolled piece of flat tin-plated copper or bronze, or a plated bronze or copper tube that is swaged to a rounded, very slightly open point. The tube wires are inserted, with solder, then the pins are heated. In any case, the tube (pin) is very nearly full of solder.

    Two things: That the pin is more a solid than a hollow tube renders some protection against kinking when bent. And, if there is a bend, it will be where there is the least amount of solder inside.

    In my experience, octals tend to splay at the base. Look at this picture (not mine): https://audiodestrukt.files.wordpress.com/2012/02/broken-glass.jpg?w=640&h=480 This shows you how those pins are inserted into the Bakelite/plastic base.

    There is considerable value in grasping the entire pin when attempting to straighten - and/or remove a bend in the tube itself. So:

    https://ijsmiami.com/product/plier-12-roundhollow-nose-5130mm-value/

    This is an off-the-shelf modern tool for the job, for those of you not able to frequent flea markets and garage sales in rural areas. German, and Box-Joint.

    But the final alignment should be done in an actual socket - something with some forgiveness, so not a ceramic socket until the pins are really straight. The, fine.

    Tips and Tricks:

    a) When re-soldering pins (and the wires inside), work with the tube restrained and on its side, not upside down. There is a potential when upside-down to melt solder onto the tube base, which could cause invisible shorts, or crack the base from thermal shock.
    b) Clean the iron tip, heat about mid-way on the pin, and add solder from the bottom
    c) Give everything plenty of time to cool before putting any stress on the pins.
    d) DO NOT use superglue anywhere near a tube, especially to re-secure it to the base. The stuff is so hard that it will not expand and contract as do the base and the glass..... *CRACK*! Electronics RTV silicone is a good material for this purpose.
    e) DO NOT use conventional RTV silicone anywhere near electronics. Acetic Acid is no good for copper or board traces.

    https://www.americansealantsinc.com/388-electronic-grade-silicone/

    Enjoy!
    sKiZo
    sKiZo

    Posts : 1527
    Join date : 2013-04-01
    Location : Michigan USA

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    Post by sKiZo on Tue Mar 19, 2019 2:09 pm

    Mostly just being careful and pulling tubes straight out can make all the difference. Firm grip on the base and push off the chassis plate with your fingers for even pressure.

    If I get some that have bent pins, I use a handy dandy "socket saver", get the pins started, and then kind of rock them a bit, pushing the tube into the saver a bit at a time till it feels right. A bit of dielectric grease on the pins before inserting them in the socket makes it a lot easier and safer to remove the tube without bending the pins again.

    Also good to remember that all pins aren't created equal. I've gotten into the habit of adjusting the fingers on the sockets every time I switch brands or tube sets. Doesn't take long to get a feel for how tight they need to be for good contact and easy tube swaps.

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