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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE! |
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7th Dec 2021, 7:55 am | #1 |
Hexode
Join Date: Apr 2017
Location: Buderim, Queensland, Australia.
Posts: 428
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One Of The Best Hints I Ever Received
When I was a very young 15 yrs old "know it all", working on a Colchester Lathe making bolts for electrical air brakes, I was having trouble with starting a large threaded ring.
I forget exactly what it was. The chief machinist, a wizened grey haired old guy, who seemed to be forever sharpening large drills and lathe bits, saw me, came over, and gave me this hint. It is so simple that I hesitate to actually post it, but here goes ... "To avoid 'cross threading' when you are assembling threaded bolts/screws/ rings etc, lay the parts together as best is possible, reverse rotate the threaded part gently until you feel or hear a click, then start rotating the part with correct rotation". This works for bolts, screws, PK screws, collars etc whether LH or RH thread, and is especially useful for fine threads on large holding rings, eg for cameras, and even hand assembly N type coax connectors. Works well when you do not want to start a new thread with PK screws in plastic etc. I remember once when working on the rotary joint for a Thomson AS909 MSSR radar, there was a 350 mm or so diameter threaded ring, which was being difficult. My mates were amazed that when I went over, I got it started in five seconds. Anyway, this advice has served me well, and I use it every day almost unconsciously. . Last edited by Radio1950; 7th Dec 2021 at 7:57 am. Reason: Getting older day by day |
7th Dec 2021, 8:28 am | #2 |
Heptode
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 648
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Re: One Of The Best Hints I Ever Received
Yes, I do that too. I learnt it from my father somewhere around 60 years ago.
Hugh |
7th Dec 2021, 8:32 am | #3 |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,296
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Re: One Of The Best Hints I Ever Received
I also do that, I have done it so long I cannot remember who told me the hint but it works.
Peter |
7th Dec 2021, 8:39 am | #4 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,980
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Re: One Of The Best Hints I Ever Received
My dad was a time-served engineering apprentice, back in the day that you signed 7 year indentures. I got a lot of tips from him, including the turning backwards until you feel the click trick.
The other one is if a nut is being difficult, turn it so it is tightening further and then try again. Craig
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7th Dec 2021, 9:35 am | #5 | |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,830
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Re: One Of The Best Hints I Ever Received
Quote:
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7th Dec 2021, 9:35 am | #6 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,326
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Re: One Of The Best Hints I Ever Received
I have always turned a screw or nut backwards to start it. Especially important screwing into plastic as if you were to start a new thread into already threaded plastic it will weaken or even strip the threaded hole. Use of powered screwdrivers is a definite no no.
Also important is to carefully note which screws you removed from an item in preparation for doing a repair. I've seen too many screws wrongly refitted, sometimes by careless repairmen and often by customers looking in case a wire had mysteriously dropped off. Another important thing is to 'use your eyes' before starting a repair - look for burnt, damaged parts, discoloration of PCB's etc. It can lead you to the fault and reduce the time needed to find a possible cause of a fault. |
7th Dec 2021, 9:43 am | #7 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,830
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Re: One Of The Best Hints I Ever Received
I disagree, they usually leave half of them OFF.
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7th Dec 2021, 9:47 am | #8 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,326
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Re: One Of The Best Hints I Ever Received
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7th Dec 2021, 11:01 am | #9 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,843
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Re: One Of The Best Hints I Ever Received
I did this in a long-established electrical shop recently, while trying a brass lampholder for size. The (very exerienced) chap behind the counter looked at me like I was an idiot and said "you're turning it the wrong way, mate"!
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7th Dec 2021, 11:09 am | #10 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,081
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Re: One Of The Best Hints I Ever Received
Yes, it works well for lampholder lampshade rings and for jam-jar lids!
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7th Dec 2021, 11:15 am | #11 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,819
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Re: One Of The Best Hints I Ever Received
Haha, yes! I do the reverse turn first, and no end of people always tell me I’m turning it the wrong way! They look even more confused when I tell them I did it on purpose! I don’t know where I learnt it, I think I worked it out myself once and just continue using it.
Regards Lloyd |
7th Dec 2021, 12:13 pm | #12 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,830
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Re: One Of The Best Hints I Ever Received
I think most people who use this method just figured it out themselves.
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7th Dec 2021, 12:21 pm | #13 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,081
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Re: One Of The Best Hints I Ever Received
Some care needs to be taken if it's a twin-start thread (as lots of jam-jar lids are, or even 3-start - but so are some precision threads, bicycle hub gear threads for instance) - you get two (or three) clicks very close together. Make sure you've got them all.
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7th Dec 2021, 3:45 pm | #14 |
Dekatron
Join Date: Jul 2008
Location: Kington, Herefordshire, UK.
Posts: 3,670
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Re: One Of The Best Hints I Ever Received
You'd be amazed at the number of people I've come across who don't know this and should.
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7th Dec 2021, 5:00 pm | #15 |
Triode
Join Date: Mar 2019
Location: Inverness, Scotland, UK.
Posts: 25
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Re: One Of The Best Hints I Ever Received
This was one of the first things I learned as a bike mechanic - such a satisfying feeling when the bolt "finds" the thread! Good knowledge to pass on to the young 'uns
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7th Dec 2021, 7:39 pm | #16 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: One Of The Best Hints I Ever Received
I learnt this in school metalwork lessons, a minor subject that proved far more useful than I expected.
Also VERY BASIC blacksmiths work in a proper coal forge. |
7th Dec 2021, 9:25 pm | #17 |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,532
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Re: One Of The Best Hints I Ever Received
Another of those that does this, but has no idea where I learned it. But I will add that there are a few pendant lampholders that I've experienced where the shade holder ring refuses to help you when doing this, because the way they are moulded means that the thread is incomplete and the 'things' click even when completely out of alignment.
Freeing something tight by slightly tightening first works too. Something I've found many times too. The protruding part of a threaded fixing gets corroded but the thread inside the nut is largely protected. So initial loosening is fine, but after just a tiny amount of loosening (sometimes less than a turn) things start to stiffen up. If this happens, DO NOT keep applying force to overcome it. Use the same technique as when cutting threads with a tap / die. Keep working backwards and forwards in partial turns, and add a lubricant. The corrosion gets taken off, without jamming the threads. |
7th Dec 2021, 10:55 pm | #18 |
Nonode
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 2,002
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Re: One Of The Best Hints I Ever Received
I remember discovering this trick myself when trying to tighten something up.
F connectors can be tricky to tighten correctly from personal experience. I've heard alloy engine blocks can be damaged by cross-threading so it's imported to make sure bolts are screwed correctly.
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30th Dec 2021, 12:45 pm | #19 |
Octode
Join Date: Mar 2016
Location: London, UK.
Posts: 1,046
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Re: One Of The Best Hints I Ever Received
The time to really observe this rule is when working with materials that easily gall when cross-threaded. A good example is stainless screws going into stainless threads. Always use some grease, always observe the reverve-twist-until-it-clicks method - and immediately go backwards if you feel unexpected resistance when screwing in. If a screw is in any way suspect, bin it without hesitation.
Edit - another tip: if you're using detachable driver bits and the screws aren't large, then take the handle off the driver bit and hold it in your fingers. This way you won't accidentally cross-thread it due to the extra torque afforded by the handle. Put all the screws partially in with the bit alone, and do the final tightening with the handle attached. |
30th Dec 2021, 12:52 pm | #20 |
Guest
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Re: One Of The Best Hints I Ever Received
Some screws for plastic have two different height threads in a two start configuration, this may need another half turn backwards to get the right engagement. You can tell from which one is tighter/looser.
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