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Thread: Has anyone else encountered the inexplicable wrong-size stuck screw?

  1. #11

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    Quote Originally Posted by Chuck(G) View Post
    Probably a brass insert--that's good. Get out your tap set and thread all the rest to agree then get some matching screws. With the shades drawn and the lights out, nobody will ever notice...
    Actually, the bore in the keyboard is still OK because the bad screw couldn't get far enough into it to destroy it. I think it just pushed the keyboard away rather than securing it. All I have to do is to find a screw matching the original screw.

    It's probably pedantic to try to make sure all the screws are present and match, but if we are going to the trouble of restoring these machines, why not go all the way?

  2. #12
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    If it's not much trouble, I like to improve on replacements. Stainless instead of zinc-plated fasteners, etc.

    Stainless is a lot cheaper than it used to be--and will never rust or corrode.

  3. #13

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    Quote Originally Posted by Chuck(G) View Post
    If it's not much trouble, I like to improve on replacements. Stainless instead of zinc-plated fasteners, etc.

    Stainless is a lot cheaper than it used to be--and will never rust or corrode.
    In my restorations of vintage equipment I often use stainless screws. The main supplier of small sized stainless screws in the USA is PSME (Precisision Scale Model Engineering) They also have varying forms of captive nuts and a myriad of small mechanical items.

    What you see sometime with incorrect screws is simply a combination of laziness and carelessness. Sometime people who work on equipment treat it very poorly if they do not own it and they have no respect for it and use a brutal approach.

    There are some interesting stories involving screw threads:

    1) In WWII in the UK there was an apparent English Gentleman with a tweed coat and a polished British accent. He went into a hardware store and asked to buy a 3mm diameter screw with a metric thread. The hardware store guy reported him, he was a German spy who didn't have the sense to ask for an imperial screw.

    2) In another case, an Aviation engineer selected an array of screws, to retain the windscreen on a Jet that had the wrong thread & length. The widow came away in use and one of the pilots got partially pushed out of the plane and the other pilot had to hold onto his legs.

    (notice I didn't say "sucked out of a plane" nobody has ever been sucked out of a plane, they are pushed out. It is the gas mass travelling out of the plane from a zone of higher pressure to a zone of lower pressure that pushes people out of planes that have sudden holes in their fuselage. Imagine if you were in a spaceship with your suit and Helmet on, and the side wall of the ship blew out. All you have to do is to hang on long enough for the gas in the ship to leave, then there are no forces trying to push you out after it has left. When you suck a milkshake up a straw, it gets pushed from a zone of higher pressure to a zone of lower pressure in your mouth. Vacuum is merely a reduction in positive pressure to a numerical value below atmospheric pressure, that is why its numerical value can never exceed about 760mmHg , unlike actual pressure, that does the work and can exceed in value without bounds. But the whole notion of a "suction force" grabbing onto and holding something is a real enough illusion for people to believe it really exists and that you can grab something and "pull on it" when in fact the object or matter is really being pushed)

    3) Apparently the Uni-bomber got caught because of the types of screw threads, used as the bombs were partly made from scrap aircraft equipment.

  4. #14
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    Ah, so "Goldfinger" getting sucked out of a jet is just nonsense? I thought as much, though I did have a thing for the young Honor Blackman...

    One thing that's made a huge difference in my approach to stuck fasteners is the availability of battery-powered tools with percussion power. What with my battery-powered driver and ratchet, it's rare that I mess up a fastener head nowadays.

    Fasteners can drive you crazy. On my old Holdsworth Grand Touring bicycle, the headlight mount is BSW; I believe that the standard photo tripod mount is Whitworth also, although it does resemble a 1/4-20 SAE, but the fit isn't exact.

    When I scrap anything, even if it's a defunct coffeemaker, I remove and save all of the screws and bolts. You never know when you'll suddenly need a strange one.
    Last edited by Chuck(G); March 5th, 2021 at 01:51 PM.

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    I think we've all been guilty of attempting to try and use what fasteners we have around, rather than spend time and money on getting the _right_ ones.
    When I restored my WWII jeep I went through it and ended up with an ice-cream tub of Whitworth and Metric fasteners, and the correct UNC and UNF ones but half-rusted or stripped.

    On eBay it's now VERY easy to buy small box sets of say metric screws, M2, M3, M4 and M5 for instance. For my own projects I standardised on M3. At the moment I am working on something that uses number screws such as 2-64 and 6-32 and I've needed to order from a fasteners supplier as they're not at all common here anymore.

    A hopefully helpful hint on removing bolts with rounded-off heads, or screws that have been cammed out: buy some stuff called ScrewGrab:
    http://www.screwgrab.com/screw-grab.html

    I don't have any connection to them but I can honestly tell you, this stuff is pure industrial magic and has saved me many many times. A small drop on the end of a screwdriver or on a spanner (wrench), whether it's a tiny stripped screw head in some electronic gear or a rounded-off engine water pump bolt, almost always eliminates slipping.
    I don't know what it is but I suspect probably microscopic crushed sharp particles of perhaps tungsten carbide, in colloidal suspension. The particles bite into the screwdriver blade and the job. Get some, I can't recommend it enough and since so little is used it will last you years and years.

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    There are screwdrivers with specially-treated tips. I think that they serve the same purpose.

    After I picked up my battery-powered ratchet, working on my truck got to be a lot simpler. I have an air ratchet, but I have to run the compressor, haul out the air hose and then wrestle with the hose in tight spaces; a real bother. I replaced the TPS on my F150 5.0L EFI in about 45 minutes, which is pretty good, if you consider where Ford put the blinking thing (i.e. on the bottom of the throttle body next to the engine--you can't even see it, much less work on it). I re-capped the ECU; using a regular socket set would have resulted in blue air and scuffed knuckles--with a ratchet, it was a lot simpler, rusted bolts and all.

    Battery-powered impact drivers are magic, if you have the right bits for them.

  7. #17
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    Quote Originally Posted by Chuck(G) View Post
    There are screwdrivers with specially-treated tips. I think that they serve the same purpose.
    I'm curious, I've searched and not found anything like this yet, could you point me to some? Plenty of hits for screwdrivers with non-slip handles though, or vanadium or magnetic tips, or bits that Amazon claims 'anti-slip' without actually saying how or why. And even a brand-new screwdriver may still have trouble if the slot is cammed out.

  8. #18
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    There are a number of manufacturers of these, including Snap-off (if you enjoy paying just shy of $30 for a single Phillips #2 driver), but basically, you want to look for "diamond tip" drivers. I bought these a few years back and they're pretty good. However, I bought them for their generous handles more than anything (old man's hands).

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    Thanks Chuck, I hadn't seen those before. Next time I'm after a screwdriver set I will keep that in mind. I endeavour to keep tools in good condition so that may be quite some time away.

  10. #20

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    Quote Originally Posted by Chuck(G) View Post
    If it's not much trouble, I like to improve on replacements. Stainless instead of zinc-plated fasteners, etc. Stainless is a lot cheaper than it used to be--and will never rust or corrode.
    Good idea, thanks. I do see a fair bit of corrosion from time to time and it would be good to stop that. As a stopgap, I have used bins and desiccants.

    Quote Originally Posted by Hugo Holden View Post
    In my restorations of vintage equipment I often use stainless screws. The main supplier of small sized stainless screws in the USA is PSME (Precisision Scale Model Engineering)
    How do you order from them? Their website doesn't have an online store?

    For that matter, what's the best way to figure out, given a sample screw that has no markings or identification, what you need to look/ask for?

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